Spicer CTIS Troubleshooting Guide

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Spicer

CTIS

(

Central Tire Inflation System

Troubleshooting Guide

AXTS0015

)

July 2010

General Information

The description and specifications contained in the service publication are current at the time of printing.

Dana reserves the right to discontinue or modify its models and/or procedures and to change specifications at any time without notice.

IMPORTANT NOTICE

This symbol is used throughout this manual to call attention to procedures where carelessness or failure to follow specific instructions may result in personal injury and/or component damage.

Departure from the instructions, choice of tools, materials and recommended parts mentioned in this publication may jeopardize the personal safety of the service technician or vehicle operator.

Any reference to brand name in this publication is made as an example of the types of tools and materials recommended for use and should not be considered an endorsement. Equivalents may be used.

WARNING: Failure to follow indicated procedures creates a high risk of personal injury to the servicing technician.

CAUTION: Failure to follow indicated procedures may cause component damage or malfunction.

IMPORTANT: Highly recommended procedures for proper service of this unit.

Note: Additional service information not covered in the service procedures.

Always use genuine Spicer replacement parts.

Every effort has been made to endure the accuracy of all information in this guide. However, Dana Commercial Vehicle

Systems Division makes no expressed or implied warranty or representation based on the enclosed information.

Any errors or omissions may be reported to: Marketing Services Dana Commercial Vehicle Systems Division P.O. Box 4097 Kalamazoo, MI 49003

Tip: Helpful removal and installation procedures to aid in the service of this unit.

Table of Contents

General Information

Central Tire Inflation System (CTIS) . . . . . . . . . . . . . . . 1

Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Component Description . . . . . . . . . . . . . . . . . . . . . . . . 2

Central Tire Inflation System Components . . . . . . . . . . 3

Simplified System Schematic . . . . . . . . . . . . . . . . . . . . 4

Operator Instructions

Flange or Panel

Operator Controls . . . . . . . . . . . . . . . . . . . . . . . . . 5

Warning Signals . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Driver Display Module (DDM)

Operator Controls . . . . . . . . . . . . . . . . . . . . . . . . . 9

Warning Signals . . . . . . . . . . . . . . . . . . . . . . . . . 10

Diagnostics

Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Service Codes Summary . . . . . . . . . . . . . . . . . . . . . . 14

Troubleshooting Tips . . . . . . . . . . . . . . . . . . . . . . . . . 20

Service Codes

No Code

Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Service Guidelines

CTIS Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Joint Compounds and Fittings . . . . . . . . . . . . . . . . . . .59

Air Filter Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

Wire Harness

Connector Illustrations . . . . . . . . . . . . . . . . . . . . . . . .61

M939 Wiring Diagram (676422 and 676603) . . . . . . . . 62

Flange Mount Wiring Diagram . . . . . . . . . . . . . . . . . . .63

Panel Mount Wiring Diagram . . . . . . . . . . . . . . . . . . . .64

Chassis ECU with DDM Wiring Diagram

Separate Power and Switched Ignition . . . . . . . . .65

All Power Switched . . . . . . . . . . . . . . . . . . . . . . . .66

Configuration Options . . . . . . . . . . . . . . . . . . . . . . . . .67

5 Flashing Lights or DDM – Dashes "--"

4 Flashing Lights or CHECK TIRES Flashing

2 Terrain Lights on Solid or DDM – Dashes "--"

No Terrain Lights or DDM – Dashes "--"

No Terrain Lights or DDM – Blank Display

DDM – Dashes "--"

Lights Sequentially Flashing

Solid Warning Lamp or Solid OVER SPEED

No Indication or DDM – Dashes "--"

No Indication

Low Pressure (Codes 26, 27) . . . . . . . . . . . . . . . 21

Low Air Supply (Code 32) . . . . . . . . . . . . . . . . . . 23

Atmospheric (Code 35) . . . . . . . . . . . . . . . . . . . . 25

Inflate Trend (Codes 36, 37) . . . . . . . . . . . . . . . . 27

Deflate Trend (Code 14) . . . . . . . . . . . . . . . . . . . 29

PCU Sensor (Codes 33, 34) . . . . . . . . . . . . . . . . 31

Pressure Switch (Code 31) . . . . . . . . . . . . . . . . . 33

Tire Leak (Imbalance) (Codes 44, 45) . . . . . . . . . 35

Tire Leak (Confirm) (Codes 41, 42) . . . . . . . . . . 37

Between Modes (Codes 23, 24) . . . . . . . . . . . . . 39

Deflate Signal (Codes 11, 12, 16) . . . . . . . . . . . . 41

PCU Solenoid (Supply, Deflate, Control, Front,

or Rear) (Codes 51, 52, 54, 55, 56) . . . . . . . . . . 43

Power (Code 17) . . . . . . . . . . . . . . . . . . . . . . . . . 45

Display Control Communications (Code 75) . . . . 47

Configuration Error . . . . . . . . . . . . . . . . . . . . . . . 49

Speed Signal (Codes 18, 76, 77) . . . . . . . . . . . . 51

Miscellaneous Output (Codes 53, 57, 58, 67, 68) 53

Wheel Valve Shut Off (Codes 61, 62, 64, 65) . . . 55

Central Tire Inflation System (CTIS)

General Information

Spicer’s Central Tire Inflation System features driver control of tire air pressure through:

• Simple push button operation.

• Electronic braking priority for air system.

• Vehicle speed sensing and response capability.

• Self-diagnostics.

• Optional independent front and rear operation.

• Optional load selection.

Key Features

Depressurized Control Lines

The only time the system is pressurized is when changing tire pressures or during pressure checks. Wheel valves isolate the tires from the rest of the system.

Electronic Braking Priority

A pressure switch, installed in the supply tank, controls the CTIS and use of air. This optimizes and protects the brake system’s primary tank pressures during system operation.

Self-Diagnostic and Auto Shut-Down

The Spicer CTIS provides self-diagnosis during operation. If the system detects a problem, it will display a series of flashing lights on the Electronic Control Unit (ECU) panel to alert the

driver. If necessary, it will close the wheel valves and shut

down.

Diagnostic Capability

The Spicer CTIS provides for easy troubleshooting using PC-based or industry standard tools. Personal computersupported diagnostics improve troubleshooting and reduce maintenance time. The diagnostics provide for manual control of CTIS test sequences and gives historical and active service code data.

Speed/Pressure Control and Warning

If truck speed exceeds the maximum allowable speed for a given setting, a panel-mounted light is activated by CTIS to warn the driver. If speed is not reduced, the system automatically inflates the tires to the appropriate pressure.

Manual Tire Inflation/Deflation

A valve stem has been included on each wheel valve, and may be used for manual inflation, deflation, or measurement of tire pressures.

Run Flat Operation

The CTIS normally checks tire pressures at intervals of 15 minutes. If possible tire damage is detected, the system will activate Auto RUN FLA check interval to 15 seconds, helping to assure that the tire will remain inflated despite minor tire damage.

T. RUN FLAT reduces the pressure

CTIS Key Features

Component Description

General Information

Wheel Valve (WV)

All axles use a Wheel Valve (WV) at each end. Dual wheels are typically connected to one WV to provide tire pressure balance between duals. When the system is idle, the WV isolates the tire(s). A standard tank valve is included for manual inflation.

Quick Release Valve (QRV)

The Quick Release Valve (one per axle) receives pneumatic signals from the Pneumatic Control Unit (PCU) and either inflates the tires, or vents air from the tires causing them to deflate. The QRV can be vented through the air stack to provide for vehicle deep water fording.

Air Transport Valve (ATV)—Optional

The Air Transport Valve (ATV) may be added in-line between the Wheel Valve and the tire. Its purpose is to manually lower the tire pressure significantly, decreasing the height of the vehicle, to allow the vehicle to be loaded onto planes, etc. with low clearances.

Load Selection/Sensing—Optional

Electronic Control Unit (ECU)

The Electronic Control Unit (ECU) is the control center for the entire Central Tire Inflation System. The ECU receives commands from the driver through push buttons, and transmits and monitors appropriate signals throughout the system.

Pneumatic Control Unit (PCU)

The Pneumatic Control Unit (PCU) is a solenoid controlled manifold that controls the air system. It also contains the PCU sensor (transducer) which reads tire pressures.

Speed Sensor or Speed Input

Speed is read from the vehicle data link or a separate speed sensor.

Pressure Switch (PS)

The Pressure Switch (PS) acts as an electronic brake priority switch. It prevents the Central Tire Inflation System from using air from the supply tank until the brake system is fully charged. The PS also ensures that enough pressure exists for the system to operate properly.

Some CTI systems make use of either a user selectable load setting or an automatic load setting, which adjusts pressure targets based on the load of the vehicle.

Air Lines

The Central Tire Inflation System uses a dedicated pneumatic system plumbed from the vehicles’ exiting supply tank. Air lines between the Pneumatic Control Unit and the Quick Release Valves (QRV) are called “Upper Control Lines”. Air lines between the QRVs and the Wheel Valves are called “Lower Control Lines”.

General Information

RUN FLAT

EM R

MPTY

MUD

SAND S OW

PA T A L

L AD

CROSS

COUNTRY

FU L LOAD

HIGHWAY

OVER SPEED CHECK TIRES

Driver Display Module

Chassis Mount ECU

Electronic Control Unit (ECU)

• With separate operator controls

– or –

• With integrated operator controls

Pneumatic Control Unit

Pressure Switch

Air Transport Valve

(optional)

Wheel Valve

Quick Release Valve

Central Tire Inflation System Components

CTIS Components

Simplified System Schematic

Tire

Hose

Tire

Hose

To Steers

Pressure

Sensor

To D rive Axle 2

To D rive Axle 1

Load Sensor

(Optional)

Electronic

Control Unit

Pressure

Switch

To P rimary and

Secondary

Tanks

Single Channel System

System Key

Pneumatic – Upper Control Lines

Electrical

Wheel Valve

Wheel

Valve

Compressor

Speed Sensor

Air Transport

Valve (Optional)

Air Transport

Valve (Optional)

Tire

Hose

Supply Tank

Air Dryer

Tire

Hose

Tire

Hose

Tire

Hose

Supply Line

PCU

Sensor

Supply Line

Pneumatic – Lower Control Lines

Pneumatic

Control Unit

Quick

Release

Valve

Quick

Release

Valve

Wheel

Valve

Wheel

Valve

Quick

Release

Valve

Wheel

Valve

Wheel

Valve

PCU

General Information

Flange or Panel—Operator Controls

RUN FLAT

EMER

EMPTY

MUD

SAND SNOW

PARTIAL

LOAD

CROSS

COUNTRY

FULL LOAD

H GHWAY

OVER SPEED CHECK TIRES

WARNING

RUN FLAT

EMER

MUD SAND

SNOW

CROSS

COUNTRY

HIGHWAY

OVER SPEED

CHECK TIRES

EMPTY

PART AL

LOAD

FULL LOAD

Operator Instructions

The integrated push button/display is the primary interface for display of system information and for push button entry of system instructions. The following sections explain the purpose and operation of the ECU controls and display.

Terrain Selection

These keys select pressures appropriate for different surface conditions. Any mode may be selected at any time (within built in speed limitations). Depressing the button for the current mode will result in a pressure check.

HWY (Highway)—For operation on improved paved surfaces.

Load Selection (Optional)

This feature allows selection of pressures appropriate for different vehicle load conditions (full load, partial-load, empty). Switching the load setting will result in a pressure check and subsequent changing of the pressures as determined by the system.

Mode Annunciator Lights

The associated annunciator lights indicate the selected mode and signal one of two states:

XC (Cross Country)—For operation on non-paved secondary roads.

SAND (Sand)—For operation on trails and other unimproved surfaces.

EMER (Emergency)—For selection of extremely low tire pressures to help free a stuck vehicle, or to traverse a short distance over a terrain known to require very low tire pressures. Since this is an extremely low pressure, the warning lamp will flash whenever this pressure is utilized.

The EMER key is for extreme conditions only and should not be used for normal driving.

If the light is flashing:

The system is in the process of checking or changing pressures to attain the pressure(s) associated with that mode light.

Some clicking may be heard from the PCU as the system cycles to achieve the new pressure(s). A deflate will be periodically interrupted as the system checks tire pressures to determine how much further deflation is necessary.

Note: Adequate supply system pressure is required to begin

or continue any pressure changing sequence.

If the light is on steady:

The selected pressure has been achieved, the tires have been isolated and the system is depressurized. The system will cycle periodically to assure that tire pressure is maintained.

Note: The system is designed to allow tire pressure increase

due to heat buildup during vehicle use. This system will not automatically deflate these pressure buildups—a lower pressure mode must be selected to initiate a deflate.

Operator Instructions

Flange or Panel

EMER

EMPTY

MUD SAND

SNOW

PART AL

LOAD

CROSS

COUNTRY

FULL LOAD

H GHWAY

OVER SPEED

CHECK TIRES

RUN

FLAT

CAUTION

Run Flat Key and Annunciator Light

This key instructs the system to check tire pressures at more frequent intervals. This key also allows the operator to override the “4 flashing lights” (tire leak imbalance) codes and reattempt 2 lights and some 5 lights codes. (See Warning Signals in next section). While the system is in RUN FLAT mode, the RUN FLAT light will flash on and off. The “RUN FLAT” feature will automatically deselect after 10 minutes, or may be shut off by pressing the button a second time.

Selecting RUN FLAT to enable the system to inflate a significantly low tire may cause other tires on that channel to temporarily lose pressure. This condition will be corrected once the low tires is inflated to the pressure of the other tires.

Operator Instructions

Single Terrain Light

• Flashing - System is working to achieve new pressures associated with that mode light.

• Solid - Pressure is achieved, system is not active, and wheel valves are closed.

2 Terrain Lights on Solid

System has shut off, closing wheel valves, with tire pressure between two mode settings.

• Inﬂ ating or deﬂ ating tires is taking too long.

• CTIS is still operational.

• Select any mode button to re-attempt pressure change.

• On 2-channel systems, normal operation continues on unaffected channel.

• Frequent occurrences may indicate need for service.

4 Terrain Lights Flashing or CHECK TIRES Flashing

Indicates low pressure in one or more tires. Stop vehicle and identify damage.

• System shuts off, closing wheel valves, and waits for operator instruction.

• T

ire damage i

s possible.

• CTIS should not be operated if major tire damage is found. Repair tire before continuing to operate vehicle.

• On 2-channel systems, normal operation will continue on the unaffected channel.

• If tire damage is minimal, operate CTIS by selecting RUN FLAT.

Not

e: Repeated use of RUN FLAT to override mode light warnings

may result in tires inﬂ ating higher than set point.

Note: Excessive air seal leakage on cold weather startup may result in "4-5 Mode Lights" warning. If no tire damage exists, this condition will self-correct as seals warm up with use.

5 Lights Flashing

System shuts off at least one channel due to fault detection on a CTIS component.

• System closes wheel valves.

• System may periodically cycle PCU to determine if fault still exists.

• On 2-channel systems, operation may be allowed on the unaffected channel.

• Get service at next opportunity.

• No ability to override

system.

Several warning signals report operating problems. The Central Tire Inﬂ ation System uses general sequences displayed on the electronic control unit lights and an instrument panel-mounted warning lamp to identify the type and area of fault.

Flange or Panel—Warning Signals

Flange or Panel

RUN FLAT Flashing (with a Terrain Light)

RUN FLAT is selected, and tire pressures are checked at more frequent intervals.

• If RUN FLAT is pushed to clear a "4 Mode Lights" ﬂ ashing display, imbalance and conﬁ rmation fault detection is overridden for the duration of RUN FLAT.

• Turn off by depressing RUN FLAT again or it will "time-out" after 10 minutes.

Warning: RUN FLAT sho

uld not be used to inﬂ ate tires with substantial damage/defects. Use of RUN FLAT can result in other tires on channel losing pressure.

No Terrain Lights

CTIS senses either a low system voltage or an electrical fault with a Pneumatic Control Unit solenoid.

• System shuts off, closing wheel valves.

• Vehicle power i

s inadequate.

Flashing Warning Lamp and/or Buzzer or OVER SPEED Flashing

Vehicle speed is too fast for pressure selected.

• Reduce speed or select higher pressure by pressing appropriate key.

• Continued operation in this mode will result in automatic selection of more appropriate pressure setting.

• Warni

ng lamp may ﬂ ash while system is in EMERGENCY

mode.

Solid Warning Lamp or Solid OVER SPEED

ECU has seen 25-50 ignition cycles without seeing any speed signal.

• If no problem exists with speed circuit wiring or sensor, lamp will go off when vehicle is moved.

Lights Sequentially Flashing (one after another)

A conﬁ g uration error has occurred and the CTIS memory has been "reloaded" from the system defaults.

• System reloads default conﬁ g uration values.

• Pressing HWY and RUN FLAT butto

ns together may clear

display.

• Any past changes of target pressure, etc. should be updated.

Lamp on

Instrument

Panel

Lamp on

Instrument

Panel

Operator Instructions

CAUTION

Driver Display Module—Operator Controls

Display

The Driver Display Module (DDM) uses a multi-function display to indicate the current selections. The display will show HY for highway pressures, CC for cross-country pressures, SS for mud-sand-snow pressures, and E for emergency pressures.

Note: The system is designed to allow tire pressure increase

due to heat buildup during vehicle use. It will not automatically deflate these pressure buildups.

Channel Indicators

Load Selection

Vehicle load selection is represented by a horizontal bar graph under the mode display. Depress the load rocker switch to change the selection, up for increasing load and down for decreasing load.

Operating a loaded vehicle at unloaded tire pressures may result in tire overheating and reduced tire life or blowout.

Terrain Selection

The terrain selection is changed by depressing the terrain rocker switch, up to increase pressures and down to decrease pressures. Any switch operation which does not change pressures will command the system to do a pressure check.

Tire pressures for the following terrains can be programmed and may be selected by the operator:

• (HY) Highway - For travel on paved surfaces at

higher speeds.

The DDM indicates FRT or RR, respectively, for front or rear axle groups. A flashing indicator identifies a group which is changing or checking pressures. A solid indicator identifies a group that has achieved target pressure.

Service Code Indication

The DDM will not display service codes directly but will display two dashes if service is required. (Accessing the service codes requires a diagnostic tool). Also, a solid over speed indicator identifies a loss of expected vehicle speed input.

• (CC) Cross Country - For reduced speed operation

on secondary roads.

• (SS) Mud Sand Snow - For reduced speed operation

on unpaved surfaces.

• (E) Emergency - For selection of extremely low tire

pressures to help free a stuck vehicle.

The Emergency selection is for extreme conditions only and should not be used for normal driving.

Operator Instructions

Driver Display Module

Driver Display Module (DDM)—Warning Signals

CTIS includes two distinct warnings to report possible tire problems and inappropriate vehicle operation. You must take immediate action to either reduce vehicle speed or check tire condition whenever these warnings are displayed.

Over Speed Flashing

This signal reports that the vehicle speed is too fast for the pressure selected. You must either reduce speed or select a higher pressure by pressing the appropriate key. Continued operation in this mode will result in the system automatically selecting a more appropriate pressure setting.

Check Tire Flashing

This signal reports that one or more tires may be at a significantly lower pressure than the others and could indicate that a tire is not holding pressure. Blinking channel indicators (FRT or RR) indicate the fault location. Stop the vehicle immediately in a safe place and identify the extent of tire damage.

IMPORTANT

Tires can still go flat! Although the Central Tire Inflation System is designed to identify under-inflated tires and fill these tires to the desired operating pressure, you can still expect that tires will occasionally be punctured or otherwise damaged during normal use and no longer retain air reliably. A daily walk-around inspection of the vehicle at the start of the day, including a manual check of the tires, is still an important responsibility of the vehicle operator. Tire damage is more apparent after the vehicle has been idle overnight and will be more difficult to detect visually once the CTIS equipped vehicle is in operation. Although observation of excessive inflation periods through the driver interface can help identify a tire problem, you should have damaged tires replaced prior to placing the vehicle in operation.

Diagnostics

This section covers the equipment and procedures used to find and correct CTIS problems.

Test Equipment

CTIS troubleshooting can be performed at three levels:

1. PC diagnostics.

2. Handheld tester.

3. ECU warning signals (flashing light combinations).

Regardless of the testing equipment used, the troubleshooting procedures will be based upon the diagnostic service codes. Diagnostic tools offer the advantages of computer-aided testing without interpreting service codes.

CTIS Diagnostics

The onboard system diagnostics are an important feature of Spicer's CTIS. This section describes the use of service codes to identify CTIS operating problems.

The CTIS uses a code to identify service issues. The codes can be extracted from the ECU memory using a diagnostic service tool equipped with the appropriate software. Refer to the Service Codes Summary for more detailed information on service codes.

Service Codes

Test Modes

Diagnostic tools allow the system to be placed in several diagnostic modes:

Info—Display ECU information and configuration.

Codes—Active and historic codes are listed as reported by

the ECU.

Monitor (Normal)—CTIS operates normally, while status of system components is observed.

Test—The following operations can be performed on each channel (axle group):

• Check & Hold—System checks and

displays the pressures, then holds pressure in air lines (quick test of control line and seal integrity).

• Deflate—System "manually" deflates (test the

deflation signal).

flate—System "manually" inflates (test for large

• In

leaks).

• Hold—Pressure is held in control lines (test for

small leaks).

Setup—Allows the technician to modify parameters such as target tire pressures, etc.

Codes are described in the Service Codes Summary section. Some service codes identify the component that is associated with the problem. A list of possible causes is shown in order of most likely occurrence.

In addition, the system stores service codes in the memory of the ECU. These historical codes can only be accessed by a diagnostic tool. Historical codes are automatically cleared after 50 ECU resets with no active faults.

Diagnostics

Download free Dana Diagnostic T

Note:

Windows 98 or newe

Connect to diagnostic

PC Diagnostics

CAUTION

A battery charger is not an adequate source of power.

Visit www.dana.com for free download of Dana Diagnostic Tool (DDT).

PC diagnostics are easy to use and provide the quickest diagnostic capabilities.

• Retrieve historical data, faults and tire pressures.

• Pressurize system to detect leaks.

• Access troubleshooting flowcharts and service

procedures.

Attach computer to RP1210A communications box.

To use this program, an RP1210A compatible interface box and cables are needed to connect the PC to the vehicle.

For these types of interface boxes to work with the Dana Diagnostic Tool program, you must install a "RP1210 driver" program provided by the manufacturer of the interface box. If you do not have this program, it can normally be obtained from the manufacturer's web site. Please contact the manufacturer of your interface box if you have any questions regarding this process.

connector.

ool from dana.com.

Program requires

Diagnostics

Follow on-screen instructions.

Diagnostics

Handheld Tester

A Prolink handheld tester may be used to read and clear service codes and to obtain a short description of failures. The tester can initiate test sequences for controller outputs and can also read system parameters when equipped with the Dana program card.

KEN MOORE

M RO P O E SOR Y T MS NC

Pro-Link

7 8

4 5

2 3

ENTER

FUNC

Multimeter

Based upon system schematics and aided by component specific service codes, a multimeter can be used to check sensor and solenoid resistances and to find wiring harness faults. The multimeter can be used to check the Tire Pressure Control System wiring and components for:

• Continuity

• Ground

• Broken wires

• Open circuits

• Shorted circuits

• Incorrect battery voltage

Service Codes Summary

Diagnostics

The following chart provides a brief overview of the Central Tire Inflation System (CTIS) service codes and the effect on the system.

5 Flashing LIGHTs or DDM – Dashes "--"

Low Pressure 26, 27 CHANNEL PRESSURE LOSS (Channel only checks pressures): Pressure check of

Low Air Supply 32 PRESSURE SWITCH REMAINS OPEN (System non-operative until switch closes):

Code No. Causes (numbered in order of likely occurrence)

given channel returns low reading (< 5 psig) indicating an extreme loss of pressure. Repair and request pressure check to clear (press any mode button or run flat).

1) Open or broken line between PCU and wheel valve

2) Significant hub air seal leakage

3) Kinked or plugged line between supply tank and PCU

4) Faulty PCU sensor (ex. frozen water contamination)

5) PCU failure (supply off or control off)

6) Pressure switch failure (shorted closed)

For 4 minutes at vehicle speed > 20 mph pressure switch failed to close. Repair and allow pressure switch to close to clear.

1) Compressor governor cutout set too low

2) Pressure switch unplugged, or open wire

3) Faulty pressure switch (failed open)

4) Faulty compressor

5) Broken, kinked, or plugged line from compressor to supply tank

Note: Any reference to a “channel” on a single-channel

system refers to all control lines and wheel ends.

Atmospheric 35 OUT OF RANGE ATMOSPHERIC READING (System waits to check pressures):

Atmospheric pressure check indicates vented PCU pressure is outside of valid atmospheric range (5-20 psia). Repair and request pressure check to clear (press any mode button or run flat).

1) Poor ground connection to PCU sensor

2) Faulty PCU sensor (ex, frozen water contamination)

3) Faulty PCU or blocked PCU exhaust vent

Inflate Trend 36, 37 INFLATE PRESSURE LOSS (System disables given channel): Given channel loses > 6

psi while inflating. Repair and cycle ignition to clear.

1) Damaged tire or tire leakage

2) Leaking lines or seals

3) Faulty PCU (control solenoid off or additional channel stuck on)

Deflate Trend 14 FAILURE TO DEFLATE PROPERLY (System disables deflates): System gains >10 psi

pressure while attempting to deflate, or does not lower tires by even a small amount of the intended change. Repair and cycle ignition to clear.

1) Plugged or restricted PCU vent line

2) Faulty PCU relief valve

3) Poor ground connection to PCU sensor

4) Contaminated PCU

5) Faulty PCU

Service Codes Summary (continued)

Diagnostics

5 Flashing LIGHTs or DDM – Dashes "--"

PCU Sensor 33, 34 NO PCU SENSOR READING (System non-operative): No sensor voltage to ECU.

Pressure Switch 31 PRESSURE SWITCH SHORTED or FAILED CLOSED (System waits to check pres-

Code No. Causes (numbered in order of likely occurrence)

Clears 5 seconds following a valid reading.

1) Sensor is electrically disconnected

2) Pressure signal wire (XDCR SIGNAL) is shorted to ground, or open

3) PCU sensor VREF wire is shorted to ground, or open

4) Faulty sensor

PCU SENSOR READING TOO HIGH (System non-operative): Sensor voltage higher than allowed. Clears 5 seconds following a valid reading.

1) Pressure signal wire (XDCR SIGNAL) is shorted to power or XDCR VREF

2) Faulty sensor

sures): Pressure switch is read as closed, but pressure check of supply tank indicates insufficient air pressure to continue. Repair and request pressure check to clear (press any mode button or RUN FLAT).

1) Wire to pressure switch shorted to ground

2) Faulty pressure switch (failed closed)

3) Faulty PCU (leaks air during supply tank check)

5 Flashing LIGHTs and CHECK TIRES Solid

Inflate Trend 36, 37 INFLATE PRESSURE LOSS (System disables given channel): Given channel loses > 6

Code No. Causes (numbered in order of likely occurrence)

psi while inflating. Repair and cycle ignition to clear.

1) Damaged tire or tire leakage

2) Leaking lines or seals

3) Faulty PCU (control solenoid off or additional channel stuck on)

Service Codes Summary

Service Codes Summary (continued)

Diagnostics

4 Flashing LIGHTs or CHECK TIRES Flashing

Tire Leak (Imbalance) 44, 45 TIRES IMBALANCED (System only checks pressures on given channel): Pressure

Tire Leak (Confirm) 41, 42 CONFIRMATION FAILURE (System disables given channel): Given channel fails to

2 Terrain Lights on Solid or DDM – Dashes "--"

Code No. Causes (numbered in order of likely occurrence)

check indicates a tire on the given channel may be significantly lower than other tires on same channel. RUN FLAT will override this fault.

1) Significant tire pressure loss (i.e. overnight leakdown)

2) Significant tire damage or leaks

3) Leaking lines or seals

4) Contaminated wheel valve filters

5) Restricted tire valve stem

6) Faulty wheel valve (leaking back through QRV)

7) Kinked or restricted control lines

confirm 10 times in a row. RUN FLAT will override this fault.

1) Damaged tire or tire leakage

2) Leaking hose between wheel valve and tire

3) Faulty wheel valve (leaking back through QRV)

4) Restricted air passage between QRV and wheel valve

Code No. Causes (numbered in order of likely occurrence)

Between Modes 23, 24 SLOW INFLATE (Channel only checks pressures): Given channel takes too long(> 40

minutes) in active inflate (pressure switch closed) to achieve requested mode. Repair and request pressure check to clear (any mode button or run flat).

1) Insufficient air supply

2) Contaminated wheel valve filters

3) Kinked, plugged, or leaking lines

SLOW DEFLATE (Channel only checks pressures): Given channel takes too long in active deflate (> 20 minutes) to achieve requested mode. Repair and request pressure check to clear (any mode button or run flat).

1) Contaminated wheel valve filters

2) Restricted tire valve stem

3) Leaking upper control lines

4) Faulty PCU relief valve

5) Restricted QRV exhaust

6) Restricted PCU vent line

Service Codes Summary (continued)

Diagnostics

2 Terrain Lights on Solid or DDM – Dashes "--"

Deflate Signal 11, 12, 16 INCORRECT DEFLATE PRESSURE: Deflate signal reads outside of configured range

No Terrain Lights or DDM – Dashes "--"

PCU Solenoid 51, 52, 54,

Code No. Causes (numbered in order of likely occurrence)

for 30 seconds. If occurs during multi-channel deflate, system will reattempt deflates on individual channels. Repair and request pressure check to clear. (any mode button or run flat).

1) Faulty PCU relief valve

2) Leaking upper control lines

3) PCU internal leaks

4) Deflate solenoid poppet stuck in non-energized position

5) Poor ground connection to PCU sensor or faulty sensor

Code No. Causes (numbered in order of likely occurrence)

ELECTRICAL SOLENOID FAILURE (System non-operative): Solenoid fails electrical

55, 56

diagnostics for approximately 2 seconds. Repair & cycle ignition to clear.

1) Solenoid or harness wire is shorted to ground

2) Solenoid or harness wire is shorted to power

3) Faulty solenoid

No Terrain Lights or DDM – Blank Display

Power 17 POWER (System non-operative): After initialization, voltage drops below 18V for > 15

DDM – Dashes "--" Code No. Causes (numbered in order of likely occurrence)

Display Control Communications

Code No. Causes (numbered in order of likely occurrence)

seconds. Clears immediately when voltage > = 18V.

1) Low battery voltage

2) Poor ground connection to ECU

3) Poor power connection to ECU

75 NO COMMUNICATION TO DDM: ECU not receiving data from DDM user interface.

Repair to clear.

1) No data link connection to DDM (damaged harness wiring)

2) Faulty DDM

Service Codes Summary

Service Codes Summary (continued)

Diagnostics

Lights Sequentially Flashing

Configuration Error N/A CONFIGURATION ERROR (System is “Limp-Home”): System has reloaded the system

Solid Warning Lamp or Solid OVER SPEED

Speed Signal 18 NO SPEED SIGNAL (System operation is normal): ECU has been reset 25-50 times

Code No. Causes (numbered in order of likely occurrence)

defaults, eliminating any changes (target pressures, etc.) previously programmed via a diagnostic tool. Pressing HWY and RUN FLAT at the same time may clear the display...updated config data should be reprogrammed.

1) Configuration connector loose or missing

2) Faulty ECU (if repeatedly occurs)

Code No. Causes (numbered in order of likely occurrence)

without any speed input to ECU. Note: Fault will be set immediately on power up. Any speed input (driving vehicle with good speed sense operation) will clear fault.

1) Vehicle has been started approximately 25-50 times without being moved (no speed input).

2) Sensor is electrically disconnected

3) Either speed sense wire is open or shorted to ground

4) Faulty speed sensor

5) Sensor actuation failure (Tang broken/disconnected on mechanical sensor, or incorrect gap on pole sensor)

6) Both speed sense wires are shorted together

76, 77 Expected data link message not received

No Indication or DDM – Dashes "--"

Miscellaneous Output 53, 57, 58,

No Indication Code No. Causes (numbered in order of likely occurrence)

Wheel Valve Shut Off 61, 62, 64, 65LOSS OF PRESSURE DURING SHUT OFF:

Code No. Causes (numbered in order of likely occurrence)

SPARE OUTPUT OR COMPONENT FAILURE:

67, 68

1) Harness wire is shorted to ground

2) Harness wire is shorted to power

3) Faulty component

1) Wheel valve shut off failure

2) Air passage restriction

Diagnostics

Inaccurate Tire Pressures

May be caused by leaking control lines, clogged wheel valve filters or valve stems, or closed Air Transport Valves.

Run Flat Definition

Pressing the RUN FLAT button once during normal system operation puts the system in Run Flat Mode for 10 minutes and causes several things to happen:

• The RUN FLAT light will flash along with the selected mode light.

• A full pressure check (including atmospheric) is requested.

• After 10 minutes Run Flat will automatically deselect...OR... pushing RUN FLAT button again will deselect it. It can be reselected by pressing the button again after timeout.

• Tire pressures are checked at more frequent intervals.

In addition, pressing the RUN FLAT button while the ECU is displaying a “4 lights” flashing code will cause all “4 mode lights” flashing codes (imbalance and confirmation) to be overridden for the duration of RUN FLAT.

Note: ECU replacement—ECUs are NOT a typical cause of

problems. If an ECU is replaced, the system should be carefully rechecked to make sure the problem has been fixed, and does not reoccur.

Diagnostics

Troubleshooting Tips

This checklist outlines some general hints and guidelines that will be helpful in tracking down and correcting operating problems.

The ECU only displays one active code. Only the most recent service code displays on the ECU lights. In troubleshooting, be alert for related codes. Use of a diagnostic tool offers the advantage of spotting multiple active codes as well as retrieving historical codes.

A cleared code alone does not indicate a corrected problem.

A code is set by a specific fault condition and may be cleared by switching the ignition off, and then on. It’s possible to clear a code (i.e, clear the flashing lights) only to have it display again when the fault condition reoccurs. To ensure that a problem is fixed, you must run the system through the same operating modes that caused the problem and verify that the service code does not reappear.

Electrical faults are often connection problems.

The most likely cause of electrical faults will be damaged wires or connections. As a first step in troubleshooting all electrical codes, switch off vehicle ignition, then disconnect applicable connectors and inspect for damage. (Switching off the ignition is required before disconnecting the harness at the Electronic Control Unit, but is also a recommended practice before all other electrical system disconnections.) Clean or repair all bad connections before proceeding.

Disconnect the Electronic Control Unit connector with ignition off.

To avoid setting electrical fault codes, make sure that the ignition is off before unplugging the wire harness connection at the Electronic Control Unit module. Reconnect the connector before switching on the ignition.

System is not continually pressurized.

When troubleshooting pneumatic faults, keep in mind that the air system is only pressurized as needed (for example, in the inflate mode). This means that such procedures as checking for leaks require the system to be in an active pressurized state. This can be accomplished most easily by using a diagnostic tool.

Basic vehicle air and power systems are not covered in this guide.

The Central Tire Inflation System requires air pressure and electrical power supply from the base vehicle systems. Diagnosis and service of these systems is outside the scope of this manual.

2-Channel (front/rear) systems may respond differently than single-channel systems.

If a fault can be isolated to a specific channel, a 2channel system may allow continued operation on the unaffected channel. When troubleshooting, use a diagnostic tool to determine which channel has the fault.

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Codes 26, 27)

Type: Low Pressure

System Mode Condition Possible Causes (listed in order of likely occurrence)

System waits to check pressures

Faulty pneumatic system, or extremely low pressure reading

• Open line between PCU and wheel valve

• Significant hub air seal leakage

• Open solenoid (PCU electrically or pneumatically disconnected)

• Crimped or plugged line between supply tank and PCU

• Faulty PCU sensor (ex. frozen water contamination)

• PCU failure, supply or control off

• Pressure switch failure, shorted closed

• Faulty ECU

Air Pressure Check

Note that the Central Tire Inflation System is not continuously pressurized; pressure checks occur on a periodic basis. During tire pressure checks, the system delivers compressed air to each channel for approximately two seconds while monitoring the pressure in that channel.

Code Description

A “Low Pressure” code indicates an extreme low pressure reading. The most likely cause is an open line which would have a clearly audible leak during a pressure check. A secondary cause could be a faulty air delivery system (i.e. Pneumatic Control Unit [PCU]Low Pressure (Codes 26, 27) electrically or pneumatically disconnected).

Other components that can cause a Low Pressure code are:

• Electrically or pneumatically disconnected PCU

• Faulty PCU

• Restricted line between the supply tank and PCU

• Faulty PCU sensor

• Open line from PCU to Quick Release Valve

• Open line from Quick Release Valve to Wheel Valve

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Low Pressure troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Low Pressure (Codes 26,

27)

Low Pressure (Codes 26, 27)

On 2-channel systems, use the diagnostic

tool to identify the faulty channel: front or rear.

Using the diagnostic tool, initiate inflate mode

for the faulty channel.

Service Codes

Is there

extreme audible

pressure loss?

Verify that the pressure switch opens when the supply tank is below 80 psi.

Note: Primary and secondary air brake

gauges do not reflect actual pressure in

the supply tank.

Does the

pressure switch

open?

Replace pressure switch and

recheck system.

Repair faulty components

Yes

and recheck system.

Is there a restricted

line between the supply

tank and PCU?

After a pressure

check, is the pressure

reading <5 psi?

Check harness and PCU for open supply or

control solenoids. See Solenoid Fault flowchart.

Replace PCU and recheck system.

Note: While replacing the PCU, pay particular

attention to possible air line contamination (e.g.,

oil, water, particles) which may suggest further

air system maintenance needs.

Yes

Make repairs to faulty

components and recheck

Yes

Replace PCU sensor and recheck system.

system.

Does fault

reoccur?

Yes

Replace ECU and recheck system.

Note: ECUs are not a typical cause of problems. If

an ECU is replaced, the system should be carefully

rechecked to make sure the problem has been

fixed and does not reoccur.

Complete

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Code 32)

Type: Low Air Supply

System Mode Condition Possible Causes (listed in order of likely occurrence)

System waits to check pressures

Pressure switch won’t close

• Compressor governor cutout set too low

• Air dryer needs service

• Pressure switch unplugged

• Faulty pressure switch

• Faulty compressor

• Open or broken line from supply tank to PCU

• Crimped or plugged line from supply tank to PCU

Air Pressure Check

Note that the Central Tire Inflation System is not continuously pressurized; pressure checks occur on a periodic basis. During tire pressure checks, the system delivers compressed air to the tires for approximately two seconds while monitoring the pressure.

Code Description

A “Low Air Supply” code displays if system air pressure is inadequate to perform a tire pressure check.

This occurs when the pressure switch will not close. The components that can cause the pressure switch to remain open include:

Pressure Switch Harness Connector

– or –

ECU Harness Connector

D E

– or –

ABCDE ABCDE ABCDE

A C

FGHJK FGHJK FGHJK

3 2 1

• Compressor governor cutout set too low

• Pressure switch unplugged

• Faulty pressure switch

• Faulty compressor

• Open or broken line from supply tank to Pneumatic Control Unit (PCU)

• Crimped or plugged line from supply tank to PCU

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Low Air Supply troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Low Air Supply (Code 32)

When the

governor cuts out, is the

supply pressure greater than

value shown in table? (Use

calibrated pressure gauge

in tank.)

Reset governor cutout

pressure and retest system.

Is the pressure

switch plugged in?

Plug in pressure switch and

retest system.

Using the diagnostic tool, verify

pressure switch operation.

Does the

pressure switch

close above setting

shown in table?

continuity

OK?

Repair harness

and retest.

Verify air system capacity by checking

supply tank pressure buildup time.

Does the

supply tank build

up pressure?

Service code is not active. Reverify

flowchart steps and wait for fault to reoccur.

Repair vehicle air supply

system and retest.

Replace pressure switch

and retest system.

Yes

Pressure Switch

Part Number

673345 (black)

676770 (blue)

Minimum Supply

Tank Pressure

120 psig 125 psig

Identify vehicle pressure switch:

Part #673345 (black) Part #676770 (blue)

Switch off ignition. Disconnect the ECU connector and the pressure switch connector.

There are two wires used for the pressure switch (PS). One is the signal wire. The other connects the pressure switch to GROUND.

Verify continuity between:

PS Harness ECU Harness Connector Pin Connector Pin

T (Round Connector)

PS signal or

(pin A or B) G3 (Rectangular Connector) AND

ForNon-M939 Style Vehicle

PS GROUND Vehicle GROUND

(other pin A or B)

For M939 Style Vehicle

PS GROUND L (Round Connector) (other pin A or B)

Start pressure build

up in supply tank.

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Code 35)

Type: Atmospheric

System Mode Condition Possible Causes (listed in order of likely occurrence)

System waits to check pressures

PCU pressure out of range when PCU is “vented”

• Frozen water or other contaminant in PCU sensor

• Plugged PCU vent

• Poor ground connection to PCU sensor

• Faulty PCU sensor

• Faulty PCU

Air Pressure Check

Note that the Central Tire Inflation System is not continuously pressurized; pressure checks occur on a periodic basis. During tire pressure checks, the system delivers compressed air to the tires for approximately two seconds while monitoring the pressure.

Code Description

An “Atmospheric” code is logged if the atmospheric pressure reading is out of range. The atmospheric pressure reading can be out of range as a result of a blocked or restricted Pneumatic Control Unit (PCU) or vent line, contaminated PCU sensor (i.e. frozen water), air bleeding back into the PCU or because of a faulty PCU sensor.

The components that can cause this code to be set include:

PCU Sensor Harness Connector

– or –

ECU Harness Connector

D E

– or –

CAB

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

• Faulty or contaminated PCU sensor

• Faulty or contaminated PCU

• Faulty Electronic Control Unit (ECU)

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Atmospheric troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Atmospheric (Code 35)

Service Codes

Disconnect ECU and

PCU sensor connectors.

Check for continuity between:

Using the diagnostic tool, read

the atmospheric pressure.

Is the reading

between 5 and 20

psia?

Yes

Service code is not active. Reverify flowchart steps and wait

for fault to reoccur.

Is any audible

air flowing through

the PCU?

Yes

Replace PCU and recheck system.

PCU Sensor Harness ECU Harness

A (round connector) J (round connector) B (oval connector ) H3 (rectangular connector)

Disconnect harness from PCU sensor and plug new PCU sensor onto harness (do not install new sensor

in PCU yet). Verify atmospheric reading.

or or

Is there

continuity?

Yes

Is the reading within range?

Yes

niP rotcennoCniP rotcennoC

Inspect and repair faulty

harness or pins.

Complete

Note: While replacing the PCU, pay particular

attention to possible air line contamination (e.g.,

oil, water, particles) which may suggest further

air system maintenance needs.

Yes

Replace ECU and recheck system.

Note: ECUs are not a typical cause of problems. If

an ECU is replaced, the system should be carefully

rechecked to make sure the problem has been

Is the reading

within range?

fixed and does not reoccur.

Install new sensor in PCU.

Verify atmospheric reading.

Is the reading within range?

Yes

Complete

Service Codes

5 Flashing Lights or DDM – Dashes "--" or 5 Flashing Lights and Check Tires Solid (Codes 36, 37)

Type: Inflate Trend

System Mode Condition Possible Causes (listed in order of likely occurrence)

Channel inoperative

Loss of channel pressure in inflate mode

• Damaged or leaking tire

• Leaking lines

• Leaking seals

• Leaking QRV

• Leaking wheel valve

• Faulty PCU

Code Description

An “Inflate Trend” code displays when tire pressure readings are dropping while in inflate mode. Tire damage, which the compressor cannot keep up with, may have occurred after starting an inflate sequence. When possible, a 2-channel system will isolate this fault to a given channel.

The air leak can be located either before or after the wheel valve location. The components located before the wheel valve that may cause this include:

• Leaking control lines

• Leaking Quick Release Valve (QRV) exhaust port

• Leaking wheel air seals

Components located after the wheel valve that may cause this include:

•Tire damage

• Rim leaks

• Leaking air lines

• Faulty wheel valve

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Inflate Trend troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Inflate Trend (Codes 36,

37)

Inflate Trend (Codes 36, 37)

On 2-channel systems, use the

diagnostic tool to identify the

faulty channel: front or rear.

Using the diagnostic tool, initiate

inflate mode on the faulty channel.

Is there a

damaged tire?

Is there a leaking

hose between a tire

and wheel valve?

Repair tire and retest system.

Replace the hose and

retest the system.

Make sure all tires on the channel

are at the same pressures.

Is air leaking

through the QRV?

Replace the QRV and

retest the system.

Are there any

leaks in the control

lines or seals?

Is air leaking

out the PCU vent

port?

Fault code is not active.

Reverify flowchart steps and

wait for fault to reoccur.

Repair leaks and retest.

Replace PCU and retest.

Note: While replacing the PCU, pay particular

attention to possible air line contamination (e.g.,

oil, water, particles) which may suggest further

air system maintenance needs.

Yes

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Code 14)

Type: Deflate Trend

System Mode Condition Possible Causes (listed in order of likely occurrence)

Inflate only Improper deflate sequence • Upper control line leak

• Plugged or restricted PCU vent line

• Faulty PCU relief valve

• Poor ground connection to PCU sensor

• Contaminated PCU

• Faulty PCU

Code Description

A “Deflate Trend” code displays when the system has determined that a deflate sequence is not functioning correctly. This is the result of either a pressure increase during a deflation, or the system failing to lower the tires even a small amount of the desired pressure drop.

Deflate Trend (Code 14)

Yes

Using the diagnostic tool, manually

deflate the tires on one channel.

While

deflating, is the

system (relief valve)

pressure within 1 psig

of nominal? *

Continue using diagnostic tool to deflate the tires to 45 psi. Use manual pressure gauge to verify all tires at 45 psi. Use diagnostic tool to select Check & Hold.

Pressure

reading < 55

psi?

2-channel

system?

Test should

be repeated for both

channels. Both channels

tested?

Are the tires

deflating?

Use diagnostic tool to

manually deflate the tires on

the other channel.

Fault is not active. Reverify flowchart

steps and wait for fault

to reoccur.

Check wheel valve filters, replace as

necessary and recheck system.

Will the tires

deflate now?

Vent wheel valve covers

and recheck system.

Repair PCU restriction and

recheck system.

Is the PCU vent line or relief valve plugged or

restricted?

Use diagnostic tool to place system into “pressure check and hold” mode. Check for upper control line leaks. Make repairs to faulty components.

Use diagnostic tool to

manually deflate the tires.

Replace PCU relief valve

and recheck system.

Perform continuity check on

front and rear channel

solenoids. See Solenoid

Fault flowchart.

Complete

Yes

2-channel

system?

Are the tires

deflating?

PCU is contaminated or faulty.

Clean, repair and/or replace

PCU as necessary and recheck

system.

Note: While replacing the PCU, pay particular attention to possible air line contamination (e.g., oil, water, particles) which may suggest further air system maintenance needs.

PCU is contaminated or faulty.

Clean, repair and/or replace

PCU as necessary and recheck

system.

Note: While replacing the PCU, pay particular attention to possible air line contamination (e.g., oil, water, particles) which may suggest further air system maintenance needs.

* Reference vehicle build

information for nominal

relief valve pressure.

While

deflating, is the

system (relief valve)

pressure within 1

psig of

nominal? *

Yes

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Codes 33, 34)

Type: PCU Sensor

System Mode Condition Possible Causes (listed in order of likely occurrence)

No operation No PCU sensor reading • Sensor electrically disconnected

• Pressure signal wire open

• Pressure signal wire shorted to ground

• PCU sensor VREF wire open

• PCU sensor VREF wire shorted to ground

• PCU sensor ground wire open

• Faulty sensor

• Faulty ECU

No operation High PCU sensor reading • Pressure signal wire shorted to VBAT or VREF

• Faulty sensor

• Faulty ECU

Code Description

A "Pneumatic Control Unit (PCU) Sensor" code occurs when the Electronic Control Unit (ECU) receives an unusually high or low reading from the PCU sensor. A diagnostic tool will specify which of the two conditions is responsible for setting the code.

Initial troubleshooting steps involve checking for a shortedto-ground or an open PCU sensor circuit.

If the circuits check out OK, secondary causes could involve a faulty sensor or a faulty ECU.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

PCU Sensor Harness Connector

– or –

ECU Harness Connector

D E

– or –

CAB

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

PCU Sensor (Codes 33, 34)

With ignition off, inspect socket

connections at ECU connector

and at PCU sensor 3-way.

Are connections

mechanically and

electrically sound?

Repair connection

as necessary.

Disconnect the ECU connector

and the PCU sensor connector.

Is there

continuity?

Check for short circuits between each pair of PCU sensor harness pins:

A and B B and C C and A

Are any

shorted?

With ignition switch on, check

voltage between PCU sensor

harness pin B (round

connector) or pin A (oval

connector) and ground.

Is voltage

between 4.9 and

5.1 V?

Is the active

fault cleared?

Complete

Replace ECU and recheck system.

Note: ECUs are not a typical cause of problems. If

an ECU is replaced, the system should be carefully

rechecked to make sure the problem has been

fixed and does not reoccur.

Replace PCU sensor.

Inspect and repair

faulty harness.

Inspect and repair

faulty harness.

Yes

Check for continuity between the following points:

PCU Sensor Harness Connector Pin ECU Harness Connector Pin

c (round connector)

C (all connectors) or

H1 (rectangular connector)

B (round connector) b (round connector)

or or

A (oval connector) H2 (rectangular connector) A (round connector) J (round connector)

or or

B (oval connector) H3 (rectangular connector)

Service Codes

5 Flashing Lights or DDM – Dashes "--" (Code 31)

Type: Pressure Switch

System Mode Condition Possible Causes (listed in order of likely occurrence)

Pressure check only

Pressure switch shorted or won’t open.

• Pressure switch wire shorted to ground

• Faulty pressure switch (failed closed)

• Faulty PCU (leaks air during supply tank check)

Air Pressure Check

Code Description

A “Pressure Switch” code displays if system air pressure is inadequate to perform a tire pressure check, yet the pressure switch status is “closed”.

This occurs when the pressure switch will not open. The components that can cause the pressure switch to remain closed include:

• Pressure switch wire shorted to ground.

• Faulty pressure switch (failed closed).

ECU Harness Connector

D E

– or –

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Pressure Switch troubleshooting tree.

Note: This feature is only available on 2-channel systems.

This fault could be logged as a result of a singlechannel system (with a single-channel Pneumatic Control Unit [PCU]) being configured as a two-channel system. See “Configuration Error” troubleshooting tree to verify correct harness configuration selection.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Pressure Switch (Code 31)

Service Codes

Identify vehicle pressure switch:

Part #673345 (black) Part #676770 (blue)

Using the diagnostic tool,

verify pressure switch

status is closed.

Is the pressure

switch plugged in?

Yes

Using the diagnostic tool, verify

pressure switch operation.

Does the

pressure switch open

below psi value shown

in table?

Yes

Plug in pressure switch

and retest system.

Switch off ignition. Disconnect the ECU connector and the pressure switch connector. Verify NO continuity between:

ECU Harness Connector Pins

T and F (round connector) or G3 and K2 (rectangular connector)

Part Number

673345 (black)

676770 (blue)

Pressure Switch

Open Value

78 psi 87 psi

Verify correct vehicle configuration.

See Configuration Error flowchart.

Use diagnostic tool to read supply pressure.

Is supply pressure

Service code is not active. Reverify

flowchart steps and wait for fault to reoccur.

accurate?

Yes

Is there

continuity?

Yes

Repair harness and retest.

Replace PCU and recheck system.

Note: While replacing the PCU, pay

particular attention to possible air line

contamination (e.g., oil, water,

particles) which may suggest further

air system maintenance needs.

Replace pressure

switch and retest

system.

Does fault

reoccur?

Yes

Replace ECU and recheck system.

Note: ECUs are not a typical cause

of problems. If an ECU is replaced,

the system should be carefully

rechecked to make sure the problem

has been fixed and does not reoccur.

Complete

Service Codes

4 Flashing Lights or CHECK TIRES Flashing (Codes 44, 45)

Type: Tire Leak (Imbalance)

Note: RUN FLAT overrides this fault.

System Mode Condition Possible Causes (listed in order of likely occurrence)

Channel only checks pressures.

Tire pressure lower on one tire than others.

• Minor tire leakage at startup (leaked overnight)

• Severe tire damage or leaks

• Contaminated wheel valve filters

• Restricted tires valve stem

• Leaking lines

• Leaking seals

• Leaking wheel valve

• Crimped or restricted control lines

Air Pressure Check

Code Description

An “Imbalance” code indicates that either the tire pressure on one tire or wheel end was read lower than the other tires, or there is an air leak someplace in the system.

Low tire pressure can be caused by a damaged tire, plugged wheel valve filter or leaking air lines. An air leak can be located either before or after the wheel valve.

Note: When using a diagnostic tool to inflate or inflate-hold a

channel with one low tire, air may be heard leaking out or the Quick Release Valves (QRV) by the higher pressure tires. This is normal and should stop once the low tire is inflated to the pressure of the other tires.

The components located before the wheel valve that may cause a “Tire Leak (Imbalance)” code include:

• Leaking wheel air seals

• Leaking control lines

Components located after the wheel valve that may cause an imbalance include:

• Damaged tire

• Rim leaks

• Clogged or restricted Wheel Valve filter or valve stem

• Leaking air lines

• Wheel valve damage

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Tire Leak (Imbalance) troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

• Restricted QRV exhaust port

Tire Leak (Imbalance)

(Codes 44, 45)

Tire Leak (Imbalance) (Codes 44, 45)

On 2-channel systems, use diagnostic tool to

identify faulty channel: front or rear.

Manually check the tire pressures on the faulty

channel at the wheel valves.

Check for a blocked QRV exhaust or

plugged wheel valve filter or valve

stem. Make repairs to faulty

components and recheck the system.

Yes

Are any wheel

readings low?

Are any wheel readings high?

Service Codes

Yes

Check the following:

Tire damage Wheel valve filter Air line leaks Wheel seal air leaks

Wheel valve leaks Repair faulty components and recheck the system.

Make repairs to faulty

components and recheck system.

Use diagnostic tool to place system into

inflate mode and check for audible leaks

(see note under Code Description on

Yes

Use diagnostic tool to place system into

“Pressure Check and Hold” mode and look

previous page).

Is there an

audible leak?

for steady hold pressure.

Was pressure

steady?

Yes

Use diagnostic tool to

vent system.

Is air leaking

from the QRV

exhaust port.

Yes

Locate the leaking wheel valve

associated with that QRV and

replace it. Recheck the system.

Check the system for

kinked lines. Repair faulty

components and recheck

the system.

Find leak and make repairs to faulty

components. Recheck system.

Service Codes

4 Flashing Lights or CHECK TIRES Flashing (Codes 41, 42)

Type: Tire Leak (Confirm)

Note: RUN FLAT overrides this fault.

System Mode Condition Possible Causes (listed in order of likely occurrence)

Channel inoperative

Channel confirmation failure • Damaged or leaking tire

• Leaking line between wheel valve and tire

• Plugged or restricted QRV

• Leaking wheel valve

• Plugged or restricted PCU vent line

• Restricted air passage between QRV and wheel valve

Air Pressure Check

Code Description

A “Tire Leak” occurs if a channel fails to confirm tire pressure. Following an inflate or deflate sequence, the Central Tire Inflation System will return to confirm, or “double-check” the new pressure. If the pressure has dropped, the system will reinflate, and then reconfirm the tires. After multiple failed confirmation attempts, the system will log a Tire Leak (Confirm) code and the system will become inoperative.

A confirmation failure can be caused by:

• Damaged or leaking tire

• Leaking air line between the wheel valve and tire

• Plugged or restricted Quick Release Valve (QRV)

• Leaking wheel valve

• Plugged or restricted Pneumatic Control Unit (PCU) vent line

• Restricted air passage between QRV and wheel valve

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Tire Leak (Confirm) troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Tire Leak (Confirm) (Codes

41, 42)

Tire Leak (Confirm) (Codes 41, 42)

Using the diagnostic

tool, initiate inflate mode.

Is there a

damaged tire?

Is there a leaking

hose between a tire

and wheel valve?

Repair tire and

retest system.

Replace the hose and

retest the system.

Use diagnostic tool to

vent system.

Does air

continue to vent

out PCU vent

line?

Is air leaking

through the QRV

exhaust?

Service code is not active.

reverify flowchart steps and

wait for fault to reoccur.

Check vent line. Identify axle where tire pressure is low. Replace QRV.

Locate the leaking wheel valve

associated with that QRV and

replace it. Recheck the system.

On 2-channel systems, use the diagnostic tool

to identify the faulty channel: front or rear.

Manually check the tire pressures on the faulty

channel at the wheel valves. A low tire(s)

indicates likely location of problem.

Yes

Check for restrictions

between QRV and

wheel valve.

Are restrictions

present?

Yes

Repair restrictions and

recheck system.

Service Codes

2 Terrain Lights on Solid or DDM – Dashes "--" (Codes 23, 24)

Type: Between Modes

System Mode Condition Possible Causes (listed in order of likely occurrence)

Pressure check only

Slow inflate • Faulty compressor

• Restricted flow at wheel valve air filters

• Crimped or plugged lines

Slow deflate • Restricted flow at wheel valve air filters or valve stem

• Leaking upper control lines

• Plugged or restricted PCU vent port

• Restricted tire valve stem

• Faulty PCU relief valve

• Restricted QRV exhaust port

Code Description

A “Between Modes” occurs if a channel inflates or deflates too slowly. The maximum allotted time for an inflate is 40 minutes, or 20 minutes for a deflate. The most likely cause for a slow inflate is a faulty compressor or similar problem resulting in inadequate air supply to the Central Tire Inflation System. The most likely cause for a slow deflate is a leaking upper control line, causing the deflate signal to be low.

If the system is able to generate a sufficient air supply, a “Between Modes” code means that a leak or restriction exists in an air passage. The components that may contain a restricted or leaking air passage include:

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Between Modes troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

• Wheel valve air filters

• Quick Release Valve (QRV)

• Pneumatic Control Unit (PCU) vent port restriction

• Air supply lines

• Restricted tire valve stem

• Faulty PCU relief valve

• Restricted QRV exhaust

Between Modes (Codes

23, 24)

Between Modes (Codes 23, 24)

Verify air system capacity by checking

air system pressure buildup time.

Does the air

supply system

build up?

Service Codes

Rebuild or replace

wheel valve.

Repair air supply system

and retest system.

Yes

On 2-channel systems, use the diagnostic tool

to identify the faulty channel: front or rear.

Using the diagnostic tool, initiate deflate mode.

Is one tire or axle

group deflating less

than the others?

Are all tires

deflating too

slowly?

Yes

On the tires or axles that deflate

slowly, check for: Restricted QRV exhaust Clogged wheel valve filters Plugged tire valve stem

Yes

While

deflating, is the

system (relief valve)

pressure within 1 psig

of nominal? *

Complete

Did system

deflate normally?

Yes

Use diagnostic tool to place system into “pressure check and hold” mode. Check for upper control line leaks. Make repairs to faulty components.

Use diagnostic tool to

manually deflate the tires.

While

deflating, is the

system (relief valve) pressure

within 1 psig of

nominal? *

Complete

Initiate inflate mode and check

for crimped or restricted lines.

* Reference vehicle build

information for nominal

relief valve pressure.

Repair PCU restriction and

recheck system.

Yes

Is the PCU vent line or relief valve plugged or

restricted?

Replace PCU relief valve

and recheck system.

Service Codes

2 Terrain Lights on Solid or DDM – Dashes "--" (Codes 11, 12, 16)

Type: Deflate Signal

System Mode Condition Possible Causes (listed in order of likely occurrence)

Inflate only Inadequate deflate signal in

the PCU and control lines

• Plugged or restricted PCU vent line

• Faulty PCU relief valve

• Faulty PCU

• Poor ground connector to PCU sensor

• Faulty PCU sensor

Code Description

A "Deflate Signal" indicates inadequate deflate signal in the Pneumatic Control Unit (PCU) or failure to sustain the signal in the control lines of a given channel.

When a deflate is requested, the system drops the control line pressure to a preset level which is established by the PCU’s relief valve. 2-channel systems may start separate channels at different times.

If the proper pressure (vehicle specific, but typically a subset of 6-22 psi) cannot be maintained by the PCU, either a Channel Deflate Loss or Loss of Deflate signal code is logged.

On 2-channel systems, if the relief valve pressure (deflate signal) cannot be maintained while both channels are deflating, the system will attempt to deflate the channels individually and will log “Deflate Signal” codes for an individual channel with a problem.

PCU Sensor Harness Connector

– or –

ECU Harness Connector

D E

– or –

CAB

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

This can be caused by:

• Faulty PCU (relief valve)

• Plugged or restricted PCU vent line

• Line leak

To correctly diagnose the faulty component, connect the Diagnostic Tool (see "Diagnostics" for test equipment and descriptions) and follow the procedure in the Deflate Signal troubleshooting tree.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Deflate Signal (Codes 11,

12, 16)

Deflate Signal (Codes 11, 12, 16)

On 2-channel systems, use the

diagnostic tool to identify the faulty

channel: front or rear.

Using the diagnostic tool, manually

deflate the tires on the faulty channel.

While

deflating, is the

system (relief valve)

pressure within 1 psig

of nominal? *

No No

Is the PCU vent line or relief valve plugged or

restricted?

Service Codes

* Reference vehicle build

information for nominal

relief valve pressure.

Check for upper control line leaks by using diagnostic tool to place system into the “Pressure Check and Hold” mode and looking for steady hold pressure. Make repairs to faulty components.

Yes

Fault is not active.

Reverify flowchart steps and

wait for fault to reoccur.

Repair wiring and

recheck system.

Perform continuity check on

deflate solenoid. See

Solenoid Fault flowchart.

Yes

Was there a

problem?

Yes

Repair PCU restriction and

recheck system.

Use diagnostic tool to manually

deflate the tires.

While

deflating, is the

system (relief valve)

pressure within 1 psig

of nominal? *

Yes

Complete

Yes

Replace PCU

relief valve.

deflating, is the

system (relief valve)

pressure within 1 psig

of nominal? *

While

Check for continuity between:

PCU Sensor Harness ECU Harness

A (round connector) J (round connector) B (oval connector ) H3 (rectangular connector)

or or

Is there continuity?

Yes

niP rotcennoCniP rotcennoC

possible air line contamination (e.g., oil, water, particles) which

Replace PCU and recheck system.

Note: While replacing the PCU, pay particular attention to

may suggest further air system maintenance needs.

Service Codes

No Terrain Lights or DDM – Dashes "--" (Codes 51, 52, 54, 55, 56)

Type: PCU Solenoid (Supply, Deflate, Control, Front, or Rear)

System Mode Condition Possible Causes (listed in order of likely occurrence)

No Operation PCU solenoid failed electri-

cal diagnostic test

• Solenoid wire shorted to ground

• Solenoid wire shorted to power

• Faulty solenoid

• Faulty ECU

Code Description

A “Solenoid Fault” code indicates an electrical fault in the Pneumatic Control Unit (PCU). System operation is disabled when these faults are detected.

The system shuts down in a fail-safe mode and turns off the power to the solenoids.

The troubleshooting tree first tests internal solenoid circuitry. Resistance outside the specified range of 30 to 80 ohms indicates a defective solenoid. Succeeding steps check continuity of the wire harness circuits between the PCU and the Electronic Control Unit (ECU). If the problem can be traced to a faulty circuit or connector, make the necessary repairs. If the troubleshooting routine leads to a problem with the solenoid itself, the PCU must be repaired or replaced. If both the solenoid and the circuitry check out OK, the ECU is faulty.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

PCU Component Connector

PCU Harness Connector

ECU Harness Connector

– or –

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

PCU Solenoid (Codes 51,

52, 54, 55, 56)

PCU Solenoid (Codes 51, 52, 54, 55, 56)

Service Codes

Use diagnostic tool to identify which solenoid to troubleshoot.

Switch off ignition. Disconnect harness at PCU connector.

Measure solenoid coil resistance on PCU connector

for identified coil. Resistance should be 30-80 ohms.

On 1-Channel Systems On 2-Channel Systems

Control: B – D Control: A – D Deflate: A – E Deflate: A – E Supply: A – F Supply: A – F

Repair or

replace connections, coils or PCU.

Repair or

replace

connections,

coils or PCU.

1. Disconnect ECU harness connector.

2. Check for continuity between:

Check for shorts between PCU connector pins D, E, F and vehicle ground. On 2-channel systems, check for shorts between PCU connector pins C, B and vehicle ground.

Yes

Front: A – C Rear: A – B

Are

resistance

measurements

OK?

Yes

Are any

pins shorted

to ground?

Each code matches one specific solenoid. When the troubleshooting instructions refer to connector test points, use chart to select the pin test point for use with the particular fault code you are diagnosing.

Supply

Deflate

Fault Code

PCU Harness Connector ECU Harness Connector (round) ECU Harness Connector (rectangular)

Measure at PCU harness connector.

Non-M939 Style Vehicle

On 1-channel systems, verify continuity between A and B. Verify no continuity between any combination of pins D, E, F on PCU harness connector and A on PCU harness connector. On 2-channel systems, verify no continuity between any combination of pins C or B on PCU harness and pin A on PCU harness.

(51)

F E D C B B C R D A

B1 B2 B3 D1 D2

Are circuits continuous?

Yes

Control

(52)

M939 Style Vehicle

Verify no continuity between D, E, F on PCU harness connector and A on PCU harness connector. Verify no continuity between D, E, F on PCU harness connector and B on PCU harness connector.

(54)

Front

(55)

Repair or

harness.

Rear

(56)

replace

PCU Solenoid Harness ECU Harness Connector Pin Connector Pin

A or

3. On 1-channel systems, also check for continuity between:

PCU Solenoid Harness ECU Harness Connector Pin Connector Pin

B or

4. Check continuity of harness pin(s) shown in table for given service code (PCU harness connector to ECU harness connector).

F (flange round connector) G (M939 round connector)

K2 (rectangular connector)

F (round connector) W (M939 round connector)

K2 (rectangular connector)

Are connections OK?

Yes

Replace ECU.

Note: ECUs are not a typical cause of problems. If an ECU is replaced,

the system should be carefully

rechecked to make sure the problem

has been fixed and does not reoccur.

Repair or

replace

harness.

Service Codes

No Terrain Lights or DDM – Blank Display (Code 17)

Type: Power

System Mode Condition Possible Causes (listed in order of likely occurrence)

No Operation Power out of range • Low voltage

• Poor ground connection to ECU

• Poor power connection to ECU

• High vehicle electrical system voltage

• Faulty ECU

Code Description

A “Power” code indicates a power fault and sets when the system power is outside a 24-volt system’s acceptable range of 18 to 32 Volts. The fault could be caused by low battery power or some other problem with the basic vehicle electrical system.

If the vehicle power system checks out satisfactorily, other possible causes include bad Electronic Control Unit (ECU) connections, or a faulty ECU.

ECU Harness Connector

D E

– or –

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

In inspecting circuits and connections for a Power code, pay particular attention to a bad ground connection, which could be causing the fault.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Power (Code 17)

Replace ECU.

Note: ECUs are not a typical

cause of problems. If an ECU is

replaced, the system should be

carefully rechecked to make

sure the problem has been fixed

and does not reoccur.

With ignition switched on but engine

not running, measure battery voltage

across battery terminals.

Is voltage

reading < 18

volts?

Base vehicle power

is out of range.

With vehicle running, measure battery

voltage across battery terminals.

Is voltage

reading > 32

volts.

Does

measured

voltage match battery

voltage reading obtained

in previous

step?

Inspect for failure in power circuit including

vehicle power panel and/or ground

connections. Repair or replace as indicated.

Reconnect ECU and

switch ignition on.

Does power

fault reoccur?

Service code is not active.

Reverify flowchart steps

and wait for fault to

reoccur.

Base vehicle power is

out of range.

Yes

Is it a chassis

mount ECU?

Yes

Switch off ignition. Disconnect the ECU connector. Check power circuit by measuring voltage between:

ECU Harness Connector Pins

K1 and K2 (rectangular connector)

Switch off ignition. Disconnect the ECU connector. Switch on ignition. Check power circuit by measuring voltage between:

ECU Harness Connector Pins

H and F (round connector)

K1 and K2 (rectangular connector)

Is battery

voltage present?

Yes

Switch on ignition. Check power circuit by measuring voltage between:

ECU Harness Connector Pins

C3 and K2 (rectangular connector)

Switch on ignition. Check power circuit by measuring voltage between:

ECU Harness Connector Pins

K1 and K2 (rectangular connector)

Service Codes

DDM – Dashes "--" (Code 75)

Type: Display Control Communications

System Mode Condition Possible Causes

(Listed in Likely Order of Occurrence)

Inflate Only Blank Display • No power to DDM

• No ground connection to DDM

• System voltage out of range (9-32 volts DC)

Inflate Only DDM displays dash dash

(nothing else on display)

• No power or ground to ECU

• DDM to ECU wires open

• DDM to ECU wires shorted to ground

• DDM to ECU wires shorted to power

• DDM to ECU wires shorted together

• Faulty Driver Display Module

• Faulty Electronic Control Unit

Code Description

Code 75 indicates a communication problem between the Electronic Control Unit (ECU) and the Driver Display Module.

All of the troubleshooting steps for code 75 involve checking the condition of Electronic Control Unit and DDM circuits. If no circuit problems are found, code 75 indicates either a faulty DDM or a faulty Electronic Control Unit.

See "Troubleshooting Tips" for general guidelines on system diagnostics.

DDM Display Harness Connector

ECU Harness Connector

ABCDE ABCDE

ABCDE

F GHJ K F GHJ K

F GHJ K

3 2 1

Display Control

Communications (Code 75)

Display Control Communications (Code 75)

Yes

Turn on ignition.

driver interface

completely

blank?

With vehicle running, measure battery

voltage across battery terminals.

Base vehicle power is out of range.

Refer to Service Manual

Does

measured

voltage match

battery voltage reading

obtained

in previous

step?

Repair harness POWER or

GROUND connections to

driver interface.

Replace DDM.

Switch ignition off. Disconnect ECU connector. Disconnect DDM connector.

Are voltages within range?

Inspect fuses/ repair harness to power ECU.

Is there continuity?

Inspect and repair

faulty

communications

circuit in harness.

Is any circuit shorted?

Inspect and repair faulty

wire or

connection.

Replace DDM. Switch on ignition.

Is driver

interface functioning

correctly?

Complete

With ignition switched on but engine

not running, measure battery

voltage across battery terminals.

Is voltage

reading >32

volts?

Is voltage

reading <9

volts?

Disconnect DDM. With ignition on, measure voltage between:

DDM Display Harness Pins

4 and 5

Base vehicle power is out of range.

Refer to Service Manual

Check continuity between:

ECU and DDM Display Harness Pin Harness Pin

J3 6 K3 7

Check for communication circuits shorted to GROUND, POWER or shorted to each other. Check between:

DDM Display Harness Pins

6 and 4 7 and 4 7 and 5 6 and 5 6 and 7

Yes

Replace ECU.

Note: ECUs are not a typical cause of

problems. If an ECU is replaced, the

system should be carefully rechecked

to make sure the problem has been

fixed and does not reoccur.

Switch ignition on. Verify adequate voltage (18-32 Vdc) between:

ECU Harness Connector Pins

POWER (K1) and GROUND (A3)

SWIGN (C3)* and GROUND (A3)

* Only on systems with separate SWIGN.

Service Codes

Lights Sequentially Flashing

Type: Configuration Error

System Mode Condition Possible Causes (listed in order of likely occurrence)

Limp Home / Normal Operation

System using default values • Harness configuration requires a downloaded file

• Loss of programmed values

Code Description

Spicer’s CTIS supports multiple vehicles or setups (tire pressure targets, etc.) within a single Electronic Control Unit (ECU). This allows the ECU to be moved from vehicle to vehicle and change its parameters according to vehicle type. Setups can either be selected through harness wiring configurations or "downloaded" to the ECU. Additional modifications can be made using Dana's PC based diagnostic tool.

A "Configuration Error" code results from one of two conditions:

• Typically it is the result of a system that has been harness selected for a downloadable configuration (customized), but has not yet been downloaded. Downloading the appropriate OEM setup file will clear the display indication. ECU’s that are marked "S-307x-xxx" normally require this special attention. A download file can be obtained from the OEM or Dana Engineering.

• In addition, on some legacy systems a "Configuration Error" code display indicates an automatic memory reload has occurred. In this the HWY and RUN FLAT buttons simultaneously will clear the display indication. The system has reloaded the system defaults into ECU memory, eliminating any customization or changes (target pressures, etc.) previously programmed.

case, pressing

Configuration Harness Connector

A B C D

Configuration Component Connector

A B C D

ECU Harness Connector

– or –

A B C D E A B C D E A B C D E

F GHJ K F G H J K F G H J K

3 2 1

The troubleshooting procedure involves verifying that the harness configuration selection wires are making a good connection. If the configuration wires are good, and the problem repeatedly occurs, the ECU may need to be replaced.

Configuration Error

Service Codes

Press HWY and RUN FLAT together.

At rectangular ECU harness connector, check for proper connection of Config 1 (pin G1) to one of the following (based on appropriate config plug):

Ground (pin K2) Power (pin K1) Float (no connection)

Did display

return to normal?

Yes

Use electrical schematic and truck build information

to determine appropriate harness configuration.

Disconnect ECU from harness.

Is ECU

connector

round?

Is Config 1

connected

properly?

YesNo

At round ECU harness connector, check for proper connection of Config 1 (pin Z) to one of the following (based on appropriate config plug):

Use truck build information to determine

appropriate OEM config file.

Download OEM config file to ECU

using PC diagnostics.

Retest.

Ground (pin F) Power (pin H) Float (no connection)

At rectangular ECU harness connector, check for proper connection of Config 2 (pin G2) to one of the following (based on appropriate config plug):

Ground (pin K2) Power (pin K1) Float (no connection)

Note: ECUs are not a typical cause of problems; however, if this fault reoccurs multiple times and wiring harness has been confirmed to be good, ECU replacement may be necessary.

Yes

Is ECU

connector

round?

Is Config 2

connected

properly?

Yes

Fault is not active. Reverify flowchart

steps and wait for fault to reoccur.

At round ECU harness connector, check for proper connection of Config 2 (pin M) to one of the following

YesNo

(based on appropriate config plug):

Ground (pin F) Power (pin H) Float (no connection)

Repair harness and/or config plug and retest.

If pressure targets, etc. were

previously changed, reprogram them.

Service Codes

Solid Warning Lamp or Solid OVER SPEED (Codes 18, 76, 77)

Type: Speed Signal

System Mode Condition Possible Causes (listed in order of likely occurrence)

Normal Operation No speed signal • ECU power cycled 50 times without vehicle being moved.

• Sensor disconnected or loose plug.

• Either speed sensor wire is open (broken wire).

• Either speed sensor wire is shorted to ground (bare wire is touching the frame).

• Faulty speed sensor.

• Sensor actuation failure.

• Tang drive broken/disconnected on mechanical sensor.

• Gap not adjusted correctly on pole sensor.

• Sensor wires shorted together.

• Expected data link message not received

Code Description

A “Speed Signal” code indicates a faulty speed sensor signal. In general, the system is configured to accept speed signals from any one of several sources (analog, digital, J1708/1587 or J1939). In this standard configuration, a loss of speed signal fault is indicated by code 18. In some specific instances, a vehicle may be configured to only accept speed from a specific data link. In these cases, codes 76 (SAE J1708/1587) and code 77 (SAE J1939) may be used to indicate a speed signal fault.

• A wiring or sensor connection.

• A misadjusted or faulty sensor.

• A missing data link speed signal. (J1708/1587 or J1939)

Note: These codes will occur if Electronic Control Unit (ECU)

power has been cycled 50 times and no speed signal is received. Fifty power cycles can occur after 25 engine starts without moving the vehicle, however the code will clear as soon as a speed signal is received.

See “Troubleshooting Tips” for general guidelines on system diagnostics.

Speed Sensor

Harness Connector

ECU Harness Connector

– or –

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

Speed Signal (Codes 18,

76, 77)

Speed Signal (Code 18, 76, 77)

Service Codes

This fault is set because the ECU has seen 25-

50 ignition cycles without sensing any speed

input. Move vehicle at greater than 5 mph.

Check adjustment on threaded

pencil speed sensor or drive tang

on mechanical speed sensor.

Sensor problem?

Switch off ignition. Disconnect speed sensor and ECU from harness. Check for shorts on ECU 30-way connector:

Round Connectors Rectangular Connector Pins

- K to Y -F2 to F3

- K to F - F2 to K2

- Y to F - F3 to K2

Yes

Did fault clear? Complete

Determine type of speed sensor input:

Digital (TTL signal from engine ECU or speedometer) Analog (pole sensor or VR type) Data Link (SAE J1708/1587 or SAE J1939)

Analog

Repair as

necessary.

Sensor type?

Digital

Yes

Data Link

Use industry standard tools to verify

data link signal is OK.

Switch off ignition. Disconnect speed input from signal source and ECU from harness Check for short on ECU connector pins:

- U to F (Round Connector)

- F1 to K2 (Rectangular Connector)

Check continuity of speed sensor input pin to ECU connector pins:

U (Round Connector) F1 (Rectangular Connector)

Check for opens:

Short speed sensor harness connector A and B together. Measure continuity between ECU connector pins:

Was a short found?

- K and Y (Round Connector)

- F2 and F3 (Rectangular Connector)

Was circuit open?

Replace speed sensor.

Yes

Repair harness

as necessary.

Repair harness

as necessary.

Repair and verify

speed signal source.

Move vehicle at

greater than 5 mph.

Did active

fault clear?

Replace ECU.

Note: ECUs are not a typical cause of problems. If an

ECU is replaced, the system should be carefully

rechecked to make sure the problem has been fixed

and does not reoccur.

Yes

Complete

Service Codes

No Indication or DDM – Dashes "--" (Implementation Specific) (Codes 53, 57, 58, 67, 68)

Type: Miscellaneous Output (Spare1, Spare2, Spare3, Warning Lamp, Buzzer)

System Mode Condition Possible Causes (listed in order of likely occurrence)

Normal Operation Miscellaneous output failed

electrical diagnostic test

• Spare output wire shorted to ground

• Spare output wire shorted to power

• Faulty component

• Faulty ECU

Code Description

A “Miscellaneous Output Fault” code indicates an electrical fault in an OEM specific spare output, warning lamp or buzzer. System operation is not affected when these faults are detected.

The troubleshooting tree first tests that the associated ECU harness pin is not shorted to ground and is continuous to the component. If continuity exists, the component must be repaired or replaced.

See "Troubleshooting Tips" for general guidelines on system diagnostics.

ECU Harness Connector

– or –

ABCDE ABCDE ABCDE

FGHJK FGHJK FGHJK

3 2 1

Service Codes

Miscellaneous Output

(Codes 53, 57, 58, 67, 68)

Replace faulty component and retest system.

Use diagnostic tool to identify which component to troubleshoot.

Switch off ignition. Disconnect harness at ECU connector and component connector.

Are circuits

continuous?

Does fault

reoccur?

Verify associated ECU harness

pin is not shorted to ground and

is continuous to component.

Repair or replace harness.

Yes

Code 53 – Flange

(Warning Lamp)

Check for continuity between:

ECU Harness Component Harness Connector Pin Connector

E Warning Lamp

Check for continuity between:

ECU Harness Component Harness Connector Pin Connector

E1 (Code 53) Component 1 E2 (Code 57) Component 2 E3 (Code 58) Component 3 J3 (Code 67) Component 4

Check for continuity between:

ECU Harness Component Harness Connector Pin Connector

L (round connector)

or Buzzer

D3 (rectangular connector)

Code 68 (Buzzer)

Code 53 – Panel, Chassis

Codes 57, 58, 67

(OEM Specific)

Replace ECU and recheck system.

Note: ECUs are not a typical cause of problems. If

an ECU is replaced, the system should be carefully

rechecked to make sure the problem has been

fixed and does not reoccur.

Complete

Miscellaneous Output (Codes 53, 57, 58, 67, 68)

Service Codes

No Indication (Codes 61, 62, 64, 65)

Type: Wheel Valve Shut Off

System Mode Condition Possible Causes (listed in order of likely occurrence)

Normal Operation Loss of pressure during

shut off

• Wheel valve shut off failure

• Air passage restriction

Air Pressure Check

The Central Tire Inflation System is not continuously pressurized; pressure checks occur on a periodic basis. During tire pressure checks, the system delivers compressed air to each channel for approximately two seconds while monitoring the pressure in that channel.

Code Description

The “Wheel Valve Shut Off” code indicates that the system is unable to confirm that tires on a given channel are able to sustain the target pressure when the channel is depressurized. After any change of pressure on a given channel, the Central Tire Inflation System will return to that channel to confirm, or "double-check" the new pressure before returning to the periodic check interval. If the pressure is not the same, or more than the last reading, the system will inflate again, and then reconfirm that channel. After 7 - 10 confirmation attempts, the system will log a code, and complete operations on the other channel. The system will classify the loss of air due to wheel valve closure as minor (codes 61 and 62 on front and rear) or major (codes 64 and 65 on front and rear respectively).

Note: Leaks from the tire(s) may be noted after the truck has

been idle overnight, as the tire(s) lose(s) air when the truck is off and the system inoperative. By observing the time required to achieve normal tire pressures after starting the vehicle, many tire punctures can be identified well before the tire incurs non-repairable damage.

A confirmation failure can be caused by:

• Damaged or leaking tire(s).

• Leaking air line between the wheel valve and tire.

• Air passage restriction between the Pneumatic Control Unit (PCU) and the wheel valve.

• Wheel valve contamination or failure.

To identify the root cause of the problem, connect the diagnostic tool (see Diagnostics Section for test equipment and descriptions) and follow the procedure in the Tire Leak (code 41) Troubleshooting Tree.

See "Troubleshooting Tips" for general guidelines on system diagnostics.

Wheel Valve Shut Off

(Codes 61, 62, 64, 65)

Wheel Valve Shut Off (Codes 61, 62, 64, 65)

Codes:

Front (61) Rear (62)

Wheel valve closure (minor)

Stop vehicle and connect the diagnostic tool to the system.

Which codes

are identified?

Check airflow and look for restrictions

between the wheel valve and PCU.

Were

restrictions

found?

Identify leaking wheel valve

and rebuild or replace. Perform checkout test.

Repair restrictions and perform checkout test.

Codes:

Front (64) Rear (65)

Wheel valve closure (major)

Codes 64, 65

Codes 61, 62

YesNo

Identify leaking wheel valve

and rebuild or replace. Perform checkout test.

Service Codes

No Code

Service Codes

Type: Miscellaneous

Condition

Operating problems that do not trigger a fault code.

ELECTRONIC CONTROL UNIT (ECU) DISPLAY

Blank ECU display or DDM display • Power fuse blown

System loses programmed tire pressure settings

TIRE PRESSURE

Diagnostic tool display shows tires at higher pressure than target, yet system does not attempt to deflate

Possible Causes*

Since a fault code was not set, these conditions may be universal and not call for a troubleshooting routine.

• Bad ground to ECU

• Bad power or switched ignition line to ECU

• Faulty ECU

• Improperly followed programming procedure

• Faulty ECU

Tire pressure rises due to temperature, are not bled off by the Central Tire Inflation System. This is normal operation.

Although the Central Tire Inflation System is self-diagnosing, there are some operating problems that do not trigger a fault code. The following chart lists these conditions along with possible causes and solutions.

Solution

Where fault codes appear, refer to the troubleshooting procedures under that code.

Check Fuses See “Power” code

Reference programming procedure

Replace ECU

System will only initiate a deflate if a mode with a lower target pressure than current target is selected

No apparent inflate or deflate

Pressure imbalance (tires on same channel at different pressures)

No inflate or deflate or particular tire • Valve stem core not removed on tire

Actual tire pressures do not match programmed targets.**

Incorrect tire pressures • System defaults to original targets

* Possible causes are listed in order of likely occurrence. ** The system is designed to allow tire pressure increase due to heat buildup during vehicle use. This system will not automatically deflate these pressure buildups—a lower pressure mode must be selected to initiate a deflate.

Pressure switch not closed See “Low Air Supply” code

Defective hose, clogged filters See “Tire Leak (Imbalance)” code

Remove hose from tire valve stem and

• Clogged wheel valve filter or valve stem

• Leaking control lines

• Faulty PCU sensor

• Replacement ECU not programmed

remove core. Replace hose. Change filter.

See "Atmospheric" and "Tire Leak (Imbalance)" codes

See “Configuration Error” code

No Code

Type: Miscellaneous

Service Codes

Condition

Operating problems that do not trigger a fault code.

AIR LEAKS

Air bleeding from rear axle vents • Air seal leaks (Extreme cold tempera-

Tires fail to deflate when lower pressures are requested

Leaking tires • Damaged tire

Air bleeding (audible) through QRV when ignition is turned off

OTHER

Apparent continuous operation, or slow inflates or deflates

Possible Causes*

Since a fault code was not set, these conditions may be universal and not call for a troubleshooting routine.

tures)

• Pneumatic system problem See “Deflate Signal” code

• Loose connection between wheel valve and tire

• Faulty wheel valve

Wheel valve is leaking back through control lines

QRV vent plugged Unplug or replace QRV

• Too long changing pressures

• Loss of pressure during inflate

Solution

Where fault codes appear, refer to the troubleshooting procedures listed under that code.

Drive vehicle to “warm up” seals

Repair as needed

Identify tire with low pressure and replace faulty wheel valve

See “Between Modes”, “Tire Leak (Confirm)”, "Inflate Trend" codes

System stopped in middle of inflate or deflate (display shows steady mode light before reaching targeted pressures)

Wheel end oil leak • Faulty air or oil seal Repair as needed

Optional “load” switch seems to have no effect

• Intermittent PCU sensor short or open See “PCU Sensor” code

• Broken, shorted, or open wire to load switch

• Faulty load switch

- Use diagnostic tool in monitor mode

to verify load status changes when switch position changes

- Use wiring diagram to test harness

for shorts or open

- Replace load switch

* Possible causes are listed in order of likely occurrence.

Service Guidelines

CTIS Service

The Central Tire Inflation System requires normal maintenance much the same as other systems on the vehicle. Following are some general rules that apply to Central Tire Inflation service:

Clean and Dry Air Supply

The Spicer Central Tire Inflation System requires a constant supply of clean dry air. An adequately sized and properly maintained air dryer is critical for continued proper operation of the Central Tire Inflation System. Even though the air dryer may be working properly, moisture can accumulate in the supply tank during normal operation due to the increase in air consumption. It is important to drain the supply tank daily. Draining the supply tank completely (releasing all air pressure) when the truck is not in use will also help keep moisture under control.

Line Replacement and Routing

When replacing air lines, do not allow kinks, sharp bends or stretching in order to ment does not appear to fit easily, it could mean you are not using the proper part or that you are not following service procedures properly. Ensure that replacement lines are the correct length and size. Be cautious of any contaminants (rubber flash, plastic particles, etc.) getting in the lines when replacing them.

tighten joints. If any tube or hose seg-

Joint Compounds and Fittings

Here are some important “Do’s” and “Don’ts” regarding the use of thread sealant:

• Do apply a thin coating of compound on male threads of pipe joints, tubing connections, and other system fittings.

• Don’t use any compound on O-ring, compression, or flare fitting connections. Instead, apply a thin coat of silicone grease to 0-rings and flares.

• Don’t use Teflon thread tape anywhere in the air sys- tem. (Teflon tape shreds can become lodged in valving.)

• Do follow manufacturer recommended guidelines when tightening fittings.

Each segment of the pneumatic system must be secured to the vehicle frame or other installed line. After completing assembly of each segment, use cable ties to anchor the segment at approximately 18” intervals.

CAUTION

Proper Central Tire Inflation System operation requires correct air line diameters and lengths. Incorrect air line replacement can affect both performance and operation of the system.

Air Filter Change

Wheel Valve with Tire Hose

Integrated Wheel Valve

Tire

Hose

Air

Filter

Air

Filter

Wheel Valve Control Port

Tire Port

Integrated

Wheel Valve

Service Guidelines

The graphic below shows the location of the air filter in each wheel valve. Air filters should not be cleaned or reused. This

filter must be replaced with a new filter whenever the tire or wheel valve is serviced. Use the illustration as reference in

completing the air filter replacement as follows:

Wheel Valve with Tire Hose

1. Working quickly to prevent air loss, remove the tire hose assembly from the fitting on the tire port (nearest the tire fill valve) of the wheel valve. Cap hose to prevent air loss.

2. Use a flat blade screwdriver to dislodge (unscrew counterclockwise) the air filter from the wheel valve. Discard the used air filter.

3. Install new air filter by pressing it straight into wheel valve tire port (oriented as shown below).

4. Remove cap and install tire hose assembly to wheel valve outlet port and torque to 16-19 lb. ft.

Integrated Wheel Valve

1. Remove all air from tire.

2. Remove valve from wheel (watch for o-rings on back).

3. Remove air filter from wheel and discard. Install new air filter by pressing it straight into the wheel (oriented as shown below).

4. Ensure both o-rings are installed on back side of valve and reinstall to wheel.

5. Re-inflate tire.

Wire Harness

Connector Illustrations (All views are looking into the connector.)

Harness Connectors Component Connectors

ECU

PCU

PCU Sensor

Diagnostic

ABCDE ABCDE ABCDE

P N M

– or –– or –

CAB

3 2 1

BF CE

ACB

– or –

CAB

F GHJ K F GHJ K F GHJ K

– or –

Pressure

Switch

Speed Sensor

Configuration

ABCD

– or –– or –

ABCD

Wire Harness

Electrical Schematics

M939 Wiring Diagram (676422 and 676603)

ECU Connector

YSPEED KSPEED

SPEED

ASPEED BSPEED

SPEED SENSOR INPUT

WARNING LAMP

POWER

**J1708A

**J1708B

**J1939(+)

**J1939(-)

SBLACKOUT

TPRESS SW

LGROUND

VGROUND

FGROUND

BLACKOUT

WARNING LAMP

PRESS SW

GROUND

BLACKOUT INPUT

WARNING LAMP

PRESSURE

SWITCH INPUT

GND

GROUND

POWER

GROUND

J1708A

J1708B

J1939

Battery Voltage = Normal

(

Ground = Blackout

VEHICLE POWER PANEL

FUSE

(+)

(-)

9-PIN

DIAGNOSTIC

+VBATT

(

IGNITION

SWITCH

Z CONFIG 1

MCONFIG 2

GROUND

SUPPLY SOL

CDEFLATE SOL

RCONTROL SOL

GROUND

cXDCR SIGNAL

bXDCR VREF

JXDCR COMMON

P**RF GND

GROUND

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

GROUND

XDCR SIGNAL

XDCR VREF

XDCR COMMON

POWER

GROUND

CONFIG 1

CONFIG 2

CONFIGURATION SELECTION

Jumper plug may tie each config line to POWER or GROUND

(

to select config. See configuration page for details.

1 - CHANNEL

PNEUMATIC CONTROLLER

SUPPLY

DEFLATE

CONTROL

N/C

PCU SENSOR

** MAY EXIST ON SOME SYSTEMS AND NOT ON OTHERS

)

PCU SENSOR

PCU Sensor Harness Connector Pin ECU Harness Connector Pin

c (round connector) C (all connectors)

B (round connector) A (oval connector) A (round connector) B (oval connector)

b (round connector)

J (round connector)

Flange Mount Wiring Diagram

JXDCR COMMON

P**RF GND

** MAY EXIST ON SOME SYSTEMS AND NOT ON OTHERS* 12V SYSTEMS ONLY

cXDCR SIGNAL

bXDCR VREF

XDCR COMMON

XDCR SIGNAL

XDCR VREF

FUSE

ECU Connector

Optional Vehicle

Interface Connector

9-PIN

DIAGNOSTIC

ASPEED

VEHICLE POWER PANEL

+VBATT

IGNITION

SWITCH

POWER

2 - CHANNEL

PNEUMATIC CONTROLLER

PCU SENSOR

U**COND SPEED

AREAR SOL

FGROUND

Z CONFIG 1

DFRONT SOL

K**SPEED

Y**SPEED

GND

J1708A

J1708B

*POWER

POWER

MCONFIG 2

SPEED SENSOR INPUT

SPEED

**WARNING LAMP

WARNING LAMP

B SUPPLY SOL

CDEFLATE SOL

RCONTROL SOL

REAR SOL

FRONT SOL

SUPPLY SOL

GROUND

DEFLATE SOL

CONTROL SOL

COND SPEED

WARNING LAMP

GROUND

DEFLATE

FRONT

REAR

SUPPLY

CONTROL

PRESS SW

PRESSURE

SWITCH INPUT

TPRESS SW

GROUND

CONDITIONED SPEED INPUT

CONFIGURATION SELECTION

Jumper plug may tie each config line to POWER or GROUND to select config. See configuration page for details.

(

)

X**J1939(-)

G**J1939(+)

**J1939 SHIELD

BUZZER OUTPUT

L**BUZZER

SBLACKOUT

BLACKOUT

BLACKOUT INPUT

Battery Voltage = Normal Ground = Blackout

(

XDCR COMMON

XDCR SIGNAL

XDCR VREF

1 - CHANNEL

PNEUMATIC CONTROLLER

PCU SENSOR

GROUND

N/C

SUPPLY SOL

GROUND

DEFLATE SOL

CONTROL SOL

DEFLATE

SUPPLY

CONTROL

GROUND

J1708A

J1708B

J1939 SHIELD

J1939

(+)

J1939

(-)

POWER

GROUND

CONFIG 1

CONFIG 2

Wire Harness

Electrical Schematics

Panel Mount Wiring Diagram

ECU Connector

**SPEED

**COND SPEED

Wire Harness

Optional Vehicle

Interface Connectors

SPEED

COND SPEED

ASPEED B

SPEED SENSOR INPUT

CONDITIONED SPEED INPUT

VR S E HECK TR S

LAD

IGWAY

AR L OAD

C SS O T Y

E PTY

SND

SOW

U AT

E ER

PRESS SW

**SPARE IN **SPARE OUT **SPARE OUT **SPARE OUT **SPARE OUT

**SPARE VREF

GROUND

*POWER

POWER

J1708A

J1708B

**J1939(+)

**J1939 SHIELD

J1BLACKOUT

D3**BUZZER

E1 E2 E3 J3 J2

BLACKOUT

PRESS SW

GROUND

BLACKOUT INPUT

PRESSURE

SWITCH INPUT

Battery Voltage = Normal

(

Ground = Blackout

BUZZER OUTPUT

(

VEHICLE POWER PANEL

GND

A2**J1939(-)

GROUND

POWER

GROUND

J1708A

J1708B

J1939

J1939 SHIELD

(+)

(-)

+VBATT

FUSE

9-PIN

DIAGNOSTIC

IGNITION

SWITCH

CONFIG 1

CONFIG 2

DEFLATE SOL

FRONT SOL

REAR SOL

XDCR VREF

SUPPLY SOL

CONTROL SOL

XDCR SIGNAL

XDCR COMMON

GROUND

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

FRONT SOL

REAR SOL

XDCR SIGNAL

XDCR VREF

XDCR COMMON

POWER

GROUND

CONFIG 1

CONFIG 2

(

2 - CHANNEL

PNEUMATIC CONTROLLER

SUPPLY

DEFLATE

CONTROL

FRONT

REAR

PCU SENSOR

** MAY EXIST ON SOME SYSTEMS AND NOT ON OTHERS* 12V SYSTEMS ONLY

CONFIGURATION SELECTION

Jumper plug may tie each config line to POWER or GROUND to select config. See configuration page for details.

)

GROUND

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

GROUND

XDCR SIGNAL

XDCR VREF

XDCR COMMON

N/C

1 - CHANNEL

PNEUMATIC CONTROLLER

SUPPLY

DEFLATE

CONTROL

PCU SENSOR

Wire Harness

Chassis ECU with DDM (Separate Power and Switched Ignition) Wiring Diagram

VEHICLE POWER PANEL

ECU CONNECTOR

K1POWER

SWIGN

GROUND

G1CONFIG 1

G2CONFIG 2

J1939 (+)

A2J1939 (-)

C1J1708 A

C2J1708 B

Note: Wire per SAE-J1939.

Note: Wire per SAE-J1708.

POWER

SWIGN

GROUND

SWIGN C

GROUND A

CONFIG 1 B

CONFIG 2 D

POWER B

GROUND A

J1939 (+) C

J1939 (-) D

J1708 A F

J1708 B G

FUSE

CONFIGURATION SELECTION

(Jumper plug may tie each conﬁg line to SWIGN or GROUND to select conﬁg. See conﬁguration page for details.)

J1939 and J1708/J1587 COMMUNICATIONS

(9-pin diagnostic connector)

+VBATT

(12V / 24V)

+VBATT

(12V / 24V)

IGNITION SWITCH

PRESS SW

COND SPEED

BUZZER D3

COMM (+)

COMM (-)

SPARE IN

SPARE OUT

SPARE VREFE3H2

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

FRONT SOL

REAR SOL

XDCR SIGNAL

XDCR VREF

XDCR COMMON

GROUND

Note: Wire per SAE-J1708.

2 - CHANNEL

PNEUMATIC CONTROLLER

GROUND

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

FRONT SOL

REAR SOL

XDCR SIGNAL

XDCR VREF

XDCR COMMON

SUPPLY

DEFLATE

CONTROL

FRONT

REAR

PCU SENSOR

PRESS SW

COND SPEED

BUZZER

COMM (+)

COMM (-)

GROUND

SWIGN

DIM/BLACK

LOAD

TERRAIN

GROUND

SWIGN

DIM/BLACK

*DIM/BLACK

*GROUND

LOAD

GROUND

SWIGN

DIM/BLACK

*DIM/BLACK

*GROUND

DIM/BLACK

SWIGN

GROUND

PRESSURE SWITCH INPUT

CONDITIONED SPEED INPUT

BUZZER OUTPUT

(battery voltage)

DRIVER

DISPLAY

MODULE

TERRAIN SWITCH

LOAD SWITCH

BLACKOUT or DIMMER

(+VBATT = normal GROUND = blackout)

SWITCHED IGNITION

(12V / 24V)

DRIVER INTERFACE

*Connections to pins 8, 9, and 10 are made internally. Earlier versions of

the switches required these connections to be made in the harness.

Wire Harness

Electrical Schematics

Chassis ECU with DDM (all Power Switched) Wiring Diagram

ECU CONNECTOR

POWER

GROUND

POWER C

GROUND A

CONFIG 1 B

CONFIG 2 D

POWER B

GROUND A

J1939 (+) C

J1939 (-) D

J1708 A F

J1708 B G

J1939 (+)

K1POWER

K2GROUND

G1CONFIG 1

G2CONFIG 2

A2J1939 (-)

C1J1708 A

C2J1708 B

Note: Wire per SAE-J1939.

Note: Wire per SAE-J1708.

VEHICLE POWER PANEL

+VBATT

(12V / 24V)

FUSE

CONFIGURATION SELECTION

(Jumper plug may tie each conﬁg line to POWER or GROUND to select conﬁg. See conﬁguration page for details.)

J1939 and J1708/J1587 COMMUNICATIONS

(9-pin diagnostic connector)

IGNITION SWITCH

PRESS SW

BUZZER D3

COMM (+)

COMM (-)

SPARE IN

SPARE OUT

SPARE VREFE3H2

FRONT SOL

REAR SOL

COND SPEED

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

XDCR SIGNAL

XDCR COMMON

XDCR VREF

GROUND

SUPPLY SOL

DEFLATE SOL

CONTROL SOL

FRONT SOL

REAR SOL

XDCR SIGNAL

XDCR VREF

XDCR COMMON

Note: Wire per SAE-J1708.

2 - CHANNEL

PNEUMATIC CONTROLLER

SUPPLY

DEFLATE

CONTROL

FRONT

REAR

PCU SENSOR

GROUND

PRESS SW

COND SPEED

COMM (+)

COMM (-)

GROUND

SWIGN

DIM/BLACK

LOAD

TERRAIN

GROUND

SWIGN

DIM/BLACK

*DIM/BLACK

*GROUND

LOAD

GROUND

SWIGN

DIM/BLACK

*DIM/BLACK

*GROUND

DIM/BLACK

GROUND

BUZZER

SWIGN

PRESSURE SWITCH INPUT

CONDITIONED SPEED INPUT

BUZZER OUTPUT

(battery voltage)

DRIVER

DISPLAY

MODULE

TERRAIN SWITCH

LOAD SWITCH

BLACKOUT or DIMMER

(+VBATT = normal GROUND = blackout)

SWITCHED IGNITION

(12V / 24V)

DRIVER INTERFACE

Connections to pins 8, 9, and 10 are made internally. Earlier versions of

the switches required these connections to be made in the harness.

Configuration Options

C A

POWER

GROUND

CONFIG 1

CONFIG 2

C A

B D

Config 0

Configurations Options

Harness Connector

C A

B D

Config 3

C A

B D

Config 6

C A

B D

Config 1

C A

B D

Config 4

C A

B D

Config 7

C A

Config 2

C A

Config 5

C A

Config 8

Wire Harness

Electrical Schematics

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For spec‘ing or service assistance, call 1-877-777-5360 or visit our website at www.dana.com

Dana Commercial Vehicle Products Group

3939 Technology Drive Maumee, Ohio, USA 43537

www.dana.com

All applications must be approved by the Application Engineering Department. Speciﬁcations and/or design are subject to change without notice or obligation. Printed in USA AXTS-0015 07/10

Spicer CTIS Troubleshooting Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

General Information

Central Tire Inflation System (CTIS)

Key Features

Component Description

Simplified System Schematic

Flange or Panel—Operator Controls

Flange or Panel—Warning Signals

Driver Display Module—Operator Controls

Diagnostics

Service Codes Summary

Troubleshooting Tips

5 Flashing Lights or DDM – Dashes "--" (Codes 26, 27)

5 Flashing Lights or DDM – Dashes "--" (Code 32)

5 Flashing Lights or DDM – Dashes "--" (Code 35)

5 Flashing Lights or DDM – Dashes "--" or 5 Flashing Lights and Check Tires Solid (Codes 36, 37)

5 Flashing Lights or DDM – Dashes "--" (Code 14)

5 Flashing Lights or DDM – Dashes "--" (Codes 33, 34)

5 Flashing Lights or DDM – Dashes "--" (Code 31)

4 Flashing Lights or CHECK TIRES Flashing (Codes 44, 45)

4 Flashing Lights or CHECK TIRES Flashing (Codes 41, 42)

2 Terrain Lights on Solid or DDM – Dashes "--" (Codes 23, 24)

2 Terrain Lights on Solid or DDM – Dashes "--" (Codes 11, 12, 16)

No Terrain Lights or DDM – Dashes "--" (Codes 51, 52, 54, 55, 56)

No Terrain Lights or DDM – Blank Display (Code 17)

DDM – Dashes "--" (Code 75)

Lights Sequentially Flashing

Solid Warning Lamp or Solid OVER SPEED (Codes 18, 76, 77)

No Indication or DDM – Dashes "--" (Implementation Specific) (Codes 53, 57, 58, 67, 68)

No Indication (Codes 61, 62, 64, 65)

No Code

Service Guidelines

Air Filter Change

M939 Wiring Diagram (676422 and 676603)

Flange Mount Wiring Diagram

Panel Mount Wiring Diagram

Chassis ECU with DDM (Separate Power and Switched Ignition) Wiring Diagram

Chassis ECU with DDM (all Power Switched) Wiring Diagram

Configuration Options