BENDIX SD-13-4983 User Manual

Bendix® EC-80™ ABS / ATC Controllers

Two Connectors

Are Used

SD-13-4983

Bendix® EC‑80™ ATC ControllerBendix® EC‑80™ ABS Controller

Three Connectors

Are Used

See SD‑13‑21021 for the Bendix® eTrac™ Automated Air Suspension Transfer System

Bendix® EC‑80™ ESP(+) Controllers will be featured in SD‑13‑4986.

INTRODUCTION

Bendix® EC‑80™ ABS and ATC controllers are members of a family of electronic Antilock Braking System (ABS) devices designed to help improve the braking characteristics of air braked vehicles ‑ including heavy‑ and medium‑duty buses, trucks, and tractors. ABS controllers are also known as Electronic Control Units (ECUs).

Bendix® ABS uses wheel speed sensors, ABS modulator valves, and an ECU to control either four or six wheels of a vehicle. By monitoring individual wheel turning motion during braking, and adjusting or pulsing the brake pressure at each wheel, the Bendix EC‑80 controller is able to optimize slip between the tire and the road surface. When excessive wheel slip, or wheel lock‑up is detected, the Bendix EC‑80 controller will activate the Pressure Modulator Valves to simulate a driver pumping the brakes. However, the Bendix EC‑80 controller is able to pump the brakes on individual wheels (or pairs of wheels) independently, and with greater speed and accuracy than a driver.

In addition to the ABS function, the ATC version of the Bendix EC‑80 controller provides an Automatic Traction Control (ATC) feature. Bendix® ATC can improve vehicle traction during acceleration, plus lateral stability while driving through curves. ATC utilizes Engine Torque Limiting (ETL) where the ECU communicates with the engine’s controller and/or Differential Braking (DB) where individual wheel brake applications are used to improve vehicle traction.

Bendix EC‑80 ATC controllers also have the capability to provide a Hill Start Assist (HSA) feature. HSA interfaces

FIGURE 1 - BENDIX® EC‑80™ ABS AND ATC CONTROLLERS

The driver is always responsible for the control and safe operation of the vehicle at all times. The Bendix® ABS system does not replace the need for a skilled, alert professional driver, reacting appropriately and in a timely manner, and using safe driving practices.

TABLE OF CONTENTS PAGE

Introduction...................................1‑2

Component/ECU Mounting.......................2‑3

ABS Off‑Road Switch and Indicator Lamp Operation.....4

Bendix EC‑80 Controller Outputs ....................4

Indicator Lamp Behavior.........................5‑6

Power‑Up Sequence ...........................6‑7

ABS Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

ATC Operation ................................8‑9

Dynamometer Test Mode .......................9‑10

Automatic Tire Size Calibration ....................10

ABS Partial Shutdown ...........................10

System Reconguration .........................11

Blink Codes ...................................13

Diagnostic Modes...............................14

Using hand‑held or PC‑based diagnostics ............16

Diagnostic Trouble Code Index ....................18

Troubleshooting: Wiring .......................32‑37

Glossary ......................................39

Appendix: J1939 SPN and FMI Codes............40‑43

GENERAL SAFETY GUIDELINES

WARNING! PLEASE READ AND

FOLLOW THESE INSTRUCTIONS

TO AVOID PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:

▲ Park the vehicle on a level surface, apply the parking

brakes and always block the wheels. Always wear personal protection equipment.

▲ Stop the engine and remove the ignition key when

working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically-charged components.

▲ Do not attempt to install, remove, disassemble or

assemble a component until you have read, and thoroughly understand, the recommended procedures. Use only the proper tools and observe all precautions pertaining to use of those tools.

▲ If the work is being performed on the vehicle’s air brake

system, or any auxiliary pressurized air systems, make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle. If the vehicle is equipped with a Bendix Bendix

DRM™ dryer reservoir module, or a Bendix

AD-9si™ air dryer, be sure to drain the purge reservoir.

▲

Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner

that safely removes all electrical power from the vehicle ▲ Never exceed manufacturer’s recommended pressures. ▲ Never connect or disconnect a hose or line containing

pressure; it may whip. Never remove a component or

plug unless you are certain all system pressure has

been depleted. ▲ Use only genuine Bendix

components and kits. Replacement hardware, tubing,

hose,  ttings, etc. must be of equivalent size, type

and strength as original equipment and be designed

speci cally for such applications and systems.

▲ Components with stripped threads or damaged parts

should be replaced rather than repaired. Do not

attempt repairs requiring machining or welding unless

speci cally stated and approved by the vehicle and

component manufacturer. ▲ Prior to returning the vehicle to service, make certain all

components and systems are restored to their proper

operating condition. ▲ For vehicles with Automatic Traction Control (ATC),

the ATC function must be disabled (ATC indicator

lamp should be ON) prior to performing any vehicle

maintenance where one or more wheels on a drive axle

are lifted off the ground and moving. ▲ The power MUST be temporarily disconnected

from the radar sensor whenever any tests USING A

DYNAMOMETER are conducted on a Bendix

Advanced

™

-equipped vehicle.

▲ You should consult the vehicle manufacturer's

operating and service manuals, and any related

literature, in conjunction with the Guidelines above.

AD-IS® air dryer system, a

brand replacement parts,

Wingman®

between the transmission and braking system to help the driver prevent the vehicle from rolling backwards when moving forward from a stationary position on steep inclines.

Bendix® EC‑80™ ATC controllers have a drag torque control feature which reduces driven‑axle wheel slip (due to driveline inertia) by communicating with the engine’s controller and increasing the engine torque.

COMPONENTS/ECU MOUNTING

The Bendix EC‑80 controller’s ABS function uses:

• Bendix® WS‑24™ wheel speed sensors (4 or 6,

depending on ECU and conguration). Each sensor is

installed with a Bendix® Sensor Clamping Sleeve

• Bendix® M‑32™ / M‑32QR™ / M‑40X™ Pressure Modulator Valves (4, 5, or 6 depending on ECU and

conguration)

• Dash‑mounted tractor ABS indicator lamp

• Service brake relay valve

• Dash‑mounted trailer ABS indicator lamp (used on all towing vehicles manufactured after March 1, 2001)

• Optional blink code activation switch

• Optional ABS off‑road switch. (Off‑road feature is not available on all ECUs ‑ See Chart 1.)

90° Speed

Sensors

FIGURE 2 - BENDIX® WS‑24™ WHEEL SPEED SENSORS

M-32QR

Modulator

™

Delivery

(Port 2)

Supply (Port 1)

Electrical

Connector

Exhaust (Port 3)

™

M-40X

Modulators

FIGURE 3 - BENDIX® M‑32™ AND M‑40X™ MODULATORS

Sensor

Clamping

Sleeve

Straight Speed

Sensors

™

M-32

Modulator

The Automatic Traction Control (ATC) function uses the following additional components:

• Traction control valve (may be integral to the service brake relay valve or a stand‑alone device)

• Dash‑mounted ATC status/indicator lamp

• J1939 serial communication to engine control module

• Stop lamp switch input (may be provided using the ECU hardware input or J1939)

• Optional ATC off‑road switch

The Hill Start (HSA) function uses the following components:

• Traction Control Valve (TCV)

• Dash‑mounted HSA status/indicator lamp

• Dash‑mounted Enable/Disable switch

• RV‑3 Pressure Reducing Valve

• DC‑4 Double Check valve

ECU MOUNTING

Bendix® EC‑80™ controllers are cab‑mounted. They are not protected against moisture and must be mounted in an environmentally protected location.

All wire harness connectors must be properly seated. The use of secondary locks is strongly recommended.

Bendix EC-80 ATC Controllers

Bendix EC‑80 ATC controllers support applications up to six sensor/six modulator (6S/6M) installations with ATC and drag torque control. They can support HSA functions. All 12 volt models support Power Line Carrier (PLC). 24 volt models do not support PLC. See Chart 1 for more details.

BENDIX EC-80 CONTROLLERS WITH PLC

Since March 1, 2001, all towing vehicles must have an in‑cab trailer ABS indicator lamp. Trailers transmit the status of the trailer ABS over the power line (the blue wire of the J560 connector) to the tractor using a PLC signal. See Figures 4 and 5.

FIGURE 4 - POWER LINE WITHOUT PLC SIGNAL

All unused ECU connectors must be covered and receive any necessary protection from moisture, etc.

ECUs utilize connectors from the AMP MCP 2.8 product family.

HARDWARE CONFIGURATIONS

Bendix® EC-80™ ABS Controllers

Bendix EC‑80 ABS controllers support four sensor/four modulator (4S/4M) applications. Certain models support Power Line Carrier (PLC) communications, with all models supporting 12 volt installations. See Chart 1 for more

details.

ECU Mounting

Bendix EC-80 ABS

controller

Bendix EC-80 ABS

PLC controller

Bendix EC-80 ATC

controller

Bendix EC-80 ATC

controller

Cab 12 4 4 - - - -

Cab 12 4 4 - - -

Cab 12 4/6 4/5/6

Cab 24 4/6 4/5/6 -

Input

Voltage

Sensors PMVs ATC

FIGURE 5 - POWER LINE WITH PLC SIGNAL

Typically the signal is broadcast by the trailer ABS ECU. The application of PLC technology for the heavy vehicle industry is known as “PLC4Trucks.” The Bendix EC‑80

Serial

Blink

Codes

CHART 1 - BENDIX® EC‑80™ CONTROLLERS AVAILABLE

Commu‑

nication

J1939

PLC

ABS

Off-

Road

ATC

Off-

Road

Retarder

Relay

PLC controller and the Bendix EC‑80 ATC controller (12 volt versions) support PLC communications in accordance with SAE J2497.

Identifying a Bendix EC-80 Controller with PLC

Refer to the information panel on the ECU label to see if the controller provides PLC.

An oscilloscope can be used to measure or identify the presence of a PLC signal on the power line. The PLC signal is an amplitude and frequency‑modulated signal.

Depending on the ltering and load on the power line,

the PLC signal amplitude can range from 5.0 mVp‑p to 7.0 Vp‑p. Suggested oscilloscope settings are AC coupling, 1 volt/div, 100 µsec/div. The signal should be measured at the ignition power input of the Bendix EC‑80 controller.

Note: An ABS trailer equipped with PLC or a PLC diagnostic tool must be connected to the vehicle in order to generate a PLC signal on the power line.

To conrm if a specic ECU uses PLC or not, see the Controller Specications box below.

BENDIX EC-80 CONTROLLER INPUTS

Battery and Ignition Inputs

The ECU operates at a nominal supply voltage of 12 or 24 volts, depending on the ECU. The battery input is connected through a 30 amp fuse directly to the battery.

The ignition input is applied by the ignition switch through a 5 amp fuse.

Vehicle axle congurations and ATC features determine

the number of Bendix WS‑24™ wheel speed sensors that must be used. A vehicle with a single rear axle requires four wheel speed sensors. Vehicles with two rear axles can utilize six wheel speed sensors for optimal ABS and ATC performance.

Diagnostic Blink Code Switch

A momentary switch that grounds the ABS indicator lamp output is used to place the ECU into the diagnostic blink code mode and is typically located on the vehicle’s dash panel.

ABS OFF-ROAD SWITCH AND INDICATOR LAMP OPERATION

The ABS off-road mode should not be used on normal, paved road surfaces because vehicle stability and steerability may be affected. When the ECU is placed in the ABS off-road mode, the ABS indicator lamp will

ash constantly to notify the vehicle operator that the

off-road mode is active.

Bendix EC‑80 ATC controllers use a dash‑mounted switch to place the ECU into the ABS off‑road mode. In some cases, ECUs may also be put into the ABS off‑road mode by one of the other vehicle control modules, using a J1939 message to the Bendix EC‑80 controller.

If you need to know if a specic ECU uses a J1939 message to operate the lamp, see the Controller Specications box below.

Ground Input

The Bendix EC‑80 controller supports one ground input.

See pages 35-37 for electrical system schematics.

ABS Indicator Lamp Ground Input

Bendix EC‑80 ECUs require a second ground input (X1‑12) for the ABS indicator lamp. The X1 wire harness connector contains an ABS indicator lamp interlock (X1‑15), which shorts the ABS indicator lamp circuit (X1‑18) to ground if the connector is removed from the ECU.

Bendix® WS-24™ Wheel Speed Sensors

Wheel speed data is provided to the Bendix EC‑80 controller from the Bendix® WS‑24™ wheel speed sensor (see Figure

2). Vehicles have an exciter ring (or “tone ring”) as part of the wheel assembly, and as the wheel turns, the teeth of the exciter ring pass the wheel speed sensor, generating an AC signal. The Bendix EC‑80 controller receives the AC signal, which varies in voltage and frequency as the wheel speed changes.

Controller Specications: If you need to know exact information about an ECU e.g. if it uses PLC, serial communications, etc., e-mail ABS@Bendix.com, specifying the ECU part number, or call:

1-800-AIR-BRAKE, 1-800-247-2725, option 2, then 1, and speak to the Bendix TechTeam.

Stop Lamp Switch (SLS)

Bendix EC‑80 ATC ECUs monitor the vehicle stop lamp status. Certain vehicle functions, such as ATC and All‑ Wheel Drive (AWD), use the status of the stop lamp to know the driver’s intention. This can be provided to the ECU via J1939 communications or hardware input.

BENDIX EC-80 CONTROLLER OUTPUTS

Bendix® M-32™, M-32QR™ and M-40X™ Pressure Modulator Valves (PMV)

The Bendix M‑32, M‑32QR and M‑40X pressure modulator valves (PMV) are operated by the Bendix EC‑80 controller to modify driver applied air pressure to the service brakes during ABS or ATC activation (See pages 6‑8). The PMV is an electro‑pneumatic control valve and is the last valve that air passes through on its way to the brake chamber. The modulator hold and release solenoids are activated to precisely modify the brake pressure during an antilock braking event. The hold solenoid is normally open and the release solenoid is normally closed.

Dash Lamps

ATC

ABS

TRLR

HSA

Mode

Ignition on ‑ start up

(trailer with PLC)

3 seconds after ignition

At Vehicle Startup

(with no Diagnostic

Trouble Codes)

ABS

Off-Road

Mode

Deep

Special Mode Operation

Mud/

Snow/

Mode

Normal

During an ATC

Event

Vehicles with Hill Start Feature: During HSA Mode Lamp OFF

Normal OFF

During an ATC

Event

ABS

Lamp

ON for 3 sec‑

onds*

Lamp OFF* Lamp OFF* Lamp OFF**

Lamp ashes

slowly (every 2.5

seconds)

‑— OR, depending on vehicle options (a vehicle can have either ABS off‑road or HSA) —

OFF Flashes quickly

ATC

Lamp

ON for 2.5

seconds*

Lamp OFF

Flashes quickly

Flashes slowly

(every 2.5

seconds)

Trailer

ABS Lamp

ON for 3

seconds**

• Uses dash switch

• Not for rm road surfaces

• Allows more wheel lock‑up (less ABS intervention)

• Mode only applies under 25 mph (Over 25 mph, the system reverts to full ABS ‑ including ATC, and ATC lamp goes off.)

• Uses dash switch

• Increases allowable wheel slip during ATC interventions

• Not for rm road surfaces

HSA

Lamp

ON for 3

seconds*

Lamp

OFF*

Comments

If any of the described lamp behaviors do

not occur — or if the lamp remains on during operation — have the vehicle serviced by a

qualied mechanic as soon as possible to

restore full system functionality.

Some vehicle manufacturers may illuminate

the trailer ABS indicator lamp at power‑up regardless of whether a PLC signal is detected from the trailer or not. Consult the vehicle manufacturer’s documentation for more details.

• The HSA lamp is illuminated only at power‑ up, or if an HSA DTC is present

• If the driver disables HSA, the HSA lamp will

ash slowly

During an Automatic Traction Control (ATC) Event Flashes quickly • Reduces wheel slip during acceleration at low speeds

During Dynamometer Mode

ABS System

Status Indicators

at Start-Up

Powered Vehicle ABS

Indicator Lamp

Trailer ABS

Indicator Lamp

(PLC Detected)**

Trailer ABS Indicator

Lamp**

(PLC Not Detected)

OFF

0.5 2.0 2.5 3.0 (sec.)1.5

Lamp ON

(ATC

Disabled)

Power

Application

• Disables ATC monitoring functions

• When not in Dynamometer Mode, an illuminated lamp indicates an ATC DTC is present

ATC System

Status Indicator

at Start-Up

ATC

enabled

No ATC

0.5 2.0 2.5 3.0 (sec.)1.5

OFF

Power

Application

CHART 2 - BENDIX® EC‑80™ INDICATOR LAMP BEHAVIOR

Traction Control Valve (TCV)

Bendix EC‑80 ATC controllers will activate the TCV during differential braking ATC events. The TCV may be a separate valve or integrated into the rear axle relay valve.

ABS Indicator Lamp Control with Optional Diagnostic Blink Code Switch

Bendix® EC‑80™ controllers have internal circuitry to control the ABS indicator lamp on the dash panel.

The ABS Lamp Illuminates:

1. During power‑up (e.g. when the vehicle is started) and turns off after the self‑test is completed, providing no Diagnostic Trouble Codes (DTCs) are present on the tractor.

2. If the ECU is unplugged or has no power.

3. When the ECU is placed into the ABS off‑road mode

(the lamp ashes rapidly).

4. To display blink codes for diagnostic purposes after the external diagnostic switch is activated.

Certain Bendix® EC‑80™ controllers communicate with other vehicle control modules to operate the ABS indicator lamp using. To conrm if a specic ECU uses serial communications, see the Controller Specications box

on page 4.

Indicator Lamp Control Using Serial Communications Links

As mentioned above, depending on the vehicle manufacturer, the dash indicator lamps (ABS, ATC and trailer ABS) may be controlled using serial communications link. In these cases, the Bendix EC‑80 controller will send a serial communications message over the J1939 links indicating the required status of the lamp(s). Another vehicle control module receives the message and controls the indicator lamp(s).

Retarder Relay Disable Output

The retarder relay disable output may be used to control a retarder disable relay.

When congured to use this output, the ECU will energize

the retarder disable relay and inhibit the use of the retarder as needed.

SAE J1939 Serial Communications

A Controller Area Network (CAN) data link (SAE J1939) is provided for communication. This link is used for various functions, such as:

• To disable retarding devices during ABS operation

• To request that the torque converter disable lock‑up

during ABS operation

• To share information such as wheel speed and ECU

status with other vehicle control modules

Bendix EC‑80 ATC controllers utilize the J1939 data link for ATC and drag torque control functions.

Trailer ABS Indicator Lamp Control

Certain models of the Bendix EC‑80 controller activate a trailer ABS indicator lamp (located on the dash panel) that indicates the status of the trailer ABS unit on one, or more trailers or dollies. Typically, the Bendix EC‑80 controller directly controls the trailer ABS indicator lamp based on the information it receives from the trailer ABS.

Alternatively, some vehicles require the Bendix EC‑80 controller to activate the trailer ABS indicator lamp by communicating with other vehicle controllers using serial communications. To conrm if a specic ECU uses serial communications, see the Controller Specications box on

page 4.

ATC Lamp Output/ATC Off-Road Switch Input

The ATC dash lamp is controlled by the Bendix EC‑80 ATC ECU. The ATC lamp illuminates:

1. During power‑up (e.g. when the vehicle is started for approximately 2.5 seconds) and turns off after the self‑test is completed, providing no Diagnostic Trouble Codes are present.

2. When ATC is disabled for any reason.

3. During an ATC event (the lamp will ash rapidly at a

rate of 2.5/second).

4. When the ECU is placed in the ATC off‑road mode (the

lamp will ash steadily every 2.5 seconds). This noties

the vehicle operator that the off‑road mode is active.

Interaxle Differential Lock Control (AWD Transfer Case)

A Bendix EC‑80 ATC ECU can control the interaxle differential lock (AWD transfer case). This is recommended

on AWD vehicles, but the ECU must be specially congured

to provide this feature. For help with conguring an ECU, use the information in the Controller Specications box on page 4 to contact Bendix.

POWER-UP SEQUENCE

The vehicle operator should verify proper operation of all installed indicator lamps (ABS, ATC, and trailer ABS) when applying ignition power and during vehicle operation. See Chart 2 on page 5.

Lamps that do not illuminate as expected when ignition power is applied, or remain illuminated, indicate the need for maintenance.

ABS Indicator Lamp Operation

The ECU will illuminate the ABS indicator lamp for approximately three seconds when ignition power is applied, after which the lamp will extinguish if no Diagnostic Trouble Codes are detected.

The ECU will illuminate the ABS indicator lamp whenever full ABS operation is not available due to a Diagnostic Trouble Code. In most cases, partial ABS is still available.

ATC Status/Indicator Lamp Operation

The ECU will illuminate the ATC lamp for approximately

2.5 seconds when ignition power is applied, after which

the lamp will extinguish, if no Diagnostic Trouble Codes are detected.

The ECU will illuminate the ATC indicator lamp whenever ATC is disabled due to a Diagnostic Trouble Code.

Trailer ABS Indicator Lamp Operation

Certain models of the ECU will control the Trailer ABS indicator lamp when a PLC signal (SAE J2497) from a trailer ABS ECU is detected.

Pressure Modulator Valve Chuff Test

Bendix® EC‑80™ controllers will perform a Bendix‑patented Pressure Modulator Valve (PMV) Chuff Test. The Chuff Test is an electrical and pneumatic PMV test that can assist maintenance personnel in verifying proper PMV wiring and installation.

With brake pressure applied, a properly installed PMV will perform one sharp audible exhaust of air by activating the hold solenoid twice and the release solenoid once. If the PMV is wired incorrectly, it will produce two exhausts of air, or none at all.

The Bendix EC‑80 controller will perform a PMV chuff test on all installed modulators in the following order:

• Steer Axle Right PMV

• Steer Axle Left PMV

• Drive Axle Right PMV

• Drive Axle Left PMV

• Additional Axle Right PMV

• Additional Axle Left PMV

The pattern will then repeat itself. See Figure 6.

The ECU will not perform the PMV Chuff Test when wheel speed sensors show that the vehicle is in motion.

Right Steer

Right Drive

Right

Additional

ABS OPERATION

Bendix® ABS uses wheel speed sensors, ABS modulator valves, and an ECU to control either four or six wheels of a vehicle. By monitoring individual wheel turning motion during braking, and adjusting or pulsing the brake pressure at each wheel, the Bendix EC‑80 controller is able to optimize slip between the tire and the road surface. When excessive wheel slip, or wheel lock‑up, is detected, the Bendix EC‑80 controller will activate the pressure modulator valves to simulate a driver pumping the brakes. However, the Bendix EC‑80 controller is able to pump the brakes on individual wheels (or pairs of wheels), independently, and with greater speed and accuracy than a driver.

Steer Axle Control

Although both wheels of the steer axle have their own wheel speed sensor and pressure modulator valve, the Bendix EC‑80 controller blends the applied braking force between the two steering axle brakes. This Bendix‑patented brake

application control, called Modied Individual Control (MIC),

is designed to help reduce steering wheel pull during an ABS event on road surfaces with poor traction (or areas of poor traction, e.g., asphalt road surfaces with patches of ice).

Single Drive Axle Control (4x2 Vehicle)

For vehicles with a single rear drive axle (4x2), the brakes are operated independently by the Bendix EC‑80 controller, based on the individual wheel behavior.

Dual Drive Axle Control (4S/4M Conguration)

For vehicles with dual drive axles (6x4) using a 4S/4M

conguration, one ABS modulator controls both right-side

rear wheels, and the other modulator controls both left‑ side rear wheels. Both wheels on each side receive equal brake pressure during an ABS stop. The rear wheel speed sensors must be installed on the axle with the lightest load.

Driver

Left Steer

FIGURE 6 - VEHICLE ORIENTATION (TYPICAL)

Left Drive

Additional

Left

Dual Rear Axle Control (6S/6M Conguration)

For vehicles with dual rear axles (6x4, 6x2) using a 6S/6M

conguration, the rear wheels are controlled independently.

Therefore, brake application pressure at each wheel is adjusted according to the individual wheel behavior on the road surface.

6x2 Vehicles with 6S/5M Conguration

6x2 vehicles can utilize a 6S/5M conguration, with the

additional axle (a non‑driven rear axle) having two sensors, but only one pressure modulator valve. In this case, the PMV controls both wheels on the additional axle. The additional axle wheels would receive equal brake pressure, based on the wheel that is currently experiencing the most wheel slip.

Normal Braking

During normal braking, brake pressure is delivered through the ABS PMV and into the brake chamber. If the ECU does not detect excessive wheel slip, it will not activate ABS control, and the vehicle stops with normal braking.

Retarder Brake System Control

On surfaces with low traction, application of the retarder can lead to high levels of wheel slip at the drive axle wheels, which can adversely affect vehicle stability.

To avoid this, the Bendix EC‑80 controller switches off the retarder as soon as a lock‑up is detected at one (or more) of the drive axle wheels.

When the ECU is placed in the ABS off‑road mode, it will switch off the retarder only when ABS is active on a steer axle wheel and a drive axle wheel.

Optional HSA Mode

As a driver begins to move a vehicle forward when stopped facing up an incline (or backs‑up a vehicle when facing down a slope), vehicles without Bendix Hill Start Aid/Assist (HSA) may experience rolling downhill during the delay between the release of the brakes and providing enough torque to move the vehicle up the slope.

For vehicles with Bendix HSA, the ECU receives a J1939 message from the transmission when it will need the assistance of the brakes to avoid the vehicle rolling. The HSA components apply brake pressure to select wheel‑end brakes. After three (3) seconds from the driver brake release, the HSA system releases the brake pressure. The three‑second delay allows the drive‑line components to activate while the vehicle is held in place.

The ABS off-road mode should not be used on normal, paved road surfaces because vehicle stability and steerability may be reduced. The flashing ABS indicator lamp communicates the status of this mode to the driver.

The vehicle manufacturer should provide the optional ABS off‑road function only for vehicles that operate on unpaved surfaces or that are used in off‑road applications. The vehicle OEM is responsible for ensuring that vehicles equipped with the ABS off‑road function meet all FMVSS‑121 requirements and have adequate operator indicators and instructions.

The vehicle operator activates the off‑road function with a

switch on the dash panel. A ashing ABS indicator lamp

indicates to the driver that the ABS off‑road function is engaged. To exit the ABS off‑road mode, depress and release the switch.

All-Wheel Drive (AWD) Vehicles

AWD vehicles with an engaged interaxle differential (steer axle to rear axle)/AWD transfer case may have negative effects on ABS performance. Optimum ABS performance is achieved when the lockable differentials are disengaged, allowing individual wheel control.

Bendix EC‑80 ATC controllers can be programmed

specically for this conguration to control the differential

lock/unlock solenoid in the AWD transfer case. When programmed to do so, the ECU will disengage the locked interaxle/AWD transfer case during an ABS event and reengage it once the ABS event has ended.

When using the HSA function, the ABS off-road function and the Retarder Relay output are temporarily disabled.

Optional ABS Off-Road Mode

On some road conditions, particularly when the driving surface is soft, the stopping distance with ABS may be longer than without ABS. This can occur when a locked wheel on soft ground plows up the road surface in front of the tire, changing the rolling friction value. Although vehicle stopping distance with a locked wheel may be shorter than corresponding stopping distance with ABS control, vehicle steerability and stability is reduced.

Bendix® EC‑80™ ATC controllers have an optional control mode that more effectively accommodates these soft road conditions to shorten stopping distance while maintaining optimal vehicle steerability and stability.

ATC OPERATION

ATC Functional Overview

Just as ABS improves vehicle stability during braking, ATC improves vehicle stability and traction during vehicle acceleration. The Bendix EC‑80 ATC controller’s ATC function uses the same wheel speed information and modulator control as the ABS function. The ECU detects excessive drive wheel speed; compares the speed of the front, non‑driven wheels; and reacts to help bring the wheel

spin under control. The ECU can be congured to use

engine torque limiting and/or differential braking to control wheel spin. For optimal ATC performance, both methods are recommended.

ATC Lamp Operation

The ATC lamp illuminates:

1. During power‑up (e.g. when the vehicle is started for approximately 2.5 seconds) and turns off after the self‑test is completed, providing no Diagnostic Trouble Codes are present.

2. When ATC is disabled for any reason.

3. During an ATC event (the lamp will ash rapidly at a

rate of 2.5/second). When ATC is no longer active, the ATC active/indicator lamp turns off.

4. When the ECU is placed in the ATC off‑road mode (the

lamp will ash steadily every 2.5 seconds). This noties

the vehicle operator that the off‑road mode is active.

Differential Braking

Differential braking is automatically activated when drive wheel(s) on one side of the vehicle are spinning. This typically occurs on asphalt road surfaces with patches of ice. The traction system will then lightly apply the brake to the drive wheel(s) that are spinning. The vehicle differential will then drive the wheels on the other side of the vehicle.

Differential braking is available at vehicle speeds up to 25 MPH.

Disabling ATC Engine Control and Smart ATC™ Traction Control

ATC Engine Control and Smart ATC™ traction control will be disabled under the following conditions:

1. In response to a serial communications request from an off‑board tool.

2. At power‑up until the ECU detects a service brake application.

3. If the ECU receives a J1939 message indicating that the vehicle is parked.

4. If the Dynamometer Test Mode is active. This may be accomplished via an off‑board tool or the diagnostic blink code switch.

5. When certain Diagnostic Trouble Code conditions are detected.

Disabling ATC Differential Braking

ATC differential braking is disabled under the following conditions:

1. During power‑up (e.g. when the vehicle is started), until the ECU detects a service brake application.

2. If the ECU receives a J1939 message indicating that the vehicle is parked.

3. When the Dynamometer Test Mode is active. The Dynamometer Test Mode is entered using the diagnostic blink code switch or by using a diagnostic tool (such as Bendix® ACom® Diagnostics).

4. In response to a serial communications request from a diagnostic tool.

5. During brake torque limiting to avoid overheating of the brakes.

6. When certain Diagnostic Trouble Code conditions are detected.

Engine Torque Limiting (ETL) with Smart ATC™ Traction Control

The Bendix® EC‑80™ controller uses Engine Torque Limiting to control drive axle wheel slip. This is communicated to the engine control module (using J1939), and is available at all vehicle speeds.

Optional ATC Off-Road Mode

In some road conditions, the vehicle operator may desire additional drive wheel slip when ATC is active. The Bendix EC‑80 ATC controller has an optional control mode to permit this desired performance.

The vehicle operator can activate the off‑road function with a switch on the dash panel. Alternately, a J1939 message may be used to place the vehicle in this mode. The ATC

indicator lamp will ash continually to conrm that the off-

road ATC function is engaged.

To exit the ATC off‑road mode, depress and release the ATC off‑road switch.

Drag Torque Control Functional Overview

Bendix EC‑80 ATC controllers have a feature referred to as drag torque control which reduces wheel slip on a driven axle due to driveline inertia. This condition is addressed by increasing the engine torque to overcome the inertia.

Drag torque control increases vehicle stability on low‑ traction road surfaces during down‑shifting or retarder braking.

DYNAMOMETER TEST MODE

Bendix® Smart ATC™ Traction Control

The Bendix EC‑80 ATC controller has an additional feature known as Smart ATC™ traction control. Smart ATC™ traction control monitors the accelerator pedal position (using J1939) to help provide optimum traction and vehicle stability. By knowing the driver’s intention and adapting the target slip of the drive wheels to the driving situation, the Smart ATC™ traction control allows higher wheel slip when the accelerator pedal is applied above a preset level.

The target wheel slip is decreased when driving through a curve for improved stability.

ATC must be disabled prior to conducting any dynamometer testing. When the Dynamometer Test Mode is enabled, ATC brake control and engine control, along with drag torque control, are turned off. This test mode is used to avoid torque reduction — or torque increase and brake control activation — when the vehicle is operated on a dynamometer for testing purpose.

The Dynamometer Test Mode may be activated by pressing

and releasing the diagnostic blink code switch ve (5) times

or by using a hand‑held or PC‑based diagnostic tool.

The Dynamometer Test Mode will remain active even if power to the ECU is removed and re‑applied. Press and release the blink code switch three (3) times, or use a hand‑held or PC‑based diagnostic tool to exit the test mode.

AUTOMATIC TIRE SIZE CALIBRATION

The ECU requires a precise rolling circumference ratio between steer axle and drive axle tires in order for ABS and ATC to perform in an optimal manner. For this reason, a learning process continuously takes place in which the precise ratio is calculated. This calculated value is stored in the ECU memory provided the following conditions are met:

1. Rolling‑circumference ratio is within the permissible range.

2. Vehicle speed is greater than approximately 15 MPH.

3. No acceleration or deceleration is taking place.

4. There are no active speed sensor Diagnostic Trouble Codes (DTCs).

The ECU is provided with a ratio value of 1.00 as a default setting. If the automatic tire size alignment calculates a

different value, this is used to overwrite the original gure

in the memory. This process adapts the ABS and ATC function to the vehicle.

ABS PARTIAL SHUTDOWN

Depending which component the trouble code is detected on, the ABS and ATC functions may be fully or partially disabled. Even with the ABS indicator lamp on, the Bendix EC‑80™ controller may still provide ABS function on wheels that are not affected. The ECU should be serviced as soon as possible.

Steer Axle ABS Modulator Diagnostic Trouble Code

ABS on the affected wheel is disabled. ABS and ATC on all other wheels remains active.

Drive Axle/Additional Axle ABS Modulator Diagnostic Trouble Code

ATC is disabled. ABS on the affected wheel is disabled. ABS on all other wheels remains active.

Steer Axle Wheel Speed Sensor Diagnostic Trouble Code

The wheel with the Diagnostic Trouble Code is still controlled by using input from the remaining wheel speed sensor on the front axle. ABS remains active on the rear wheels. ATC is disabled.

Acceptable Tire Sizes

The speed calculation for an exciter ring with 100 teeth is based on a default tire size of 510 revolutions per mile.

This gure is based on the actual rolling circumference of

the tires, and varies with tire size, tire wear, tire pressure, vehicle loading, etc.

The ABS response sensitivity is reduced when the actual rolling circumference is excessive on all wheels. For a 100‑tooth exciter ring, the minimum number of tire revolutions per mile is 426, and the maximum is 567. The ECU will set DTCs if the number of revolutions are out of this range.

Drive Axle/Additional Axle Wheel Speed Sensor Diagnostic Trouble Code

ATC is disabled. In a four sensor system, ABS on the affected wheel is disabled, but ABS on all other wheels remains active.

In a six sensor system, ABS remains active by using input from the remaining rear wheel speed sensor on the same side.

ATC Modulator Diagnostic Trouble Code

ATC is disabled. ABS remains active.

J1939 Communication Diagnostic Trouble Code

ATC is disabled. ABS remains active.

ECU Diagnostic Trouble Code

ABS and ATC are disabled. The system reverts to normal braking.

Voltage Diagnostic Trouble Code

While voltage is out of range, ABS and ATC are disabled. The system reverts to normal braking. When the correct voltage level is restored, full ABS and ATC function is available. Operating voltage range is 9.0 to 17.0 VDC.

Reconguring Bendix® EC-80™ Controllers

SYSTEM RECONFIGURATION

The Bendix® EC‑80™ controller is designed to allow the technician to change the default system settings (chosen by the vehicle OEM) to provide additional or customized features. When replacing an ECU, be sure to use an equivalent Bendix® replacement part number so that the standard default settings are provided.

Depending on the version, the customizable features include ABS control settings, engine module communication, etc.

Many of these settings can be recongured using a hand-

held diagnostic tool or PC‑based software, such as the Bendix® ACom® Diagnostics program.

ECU RECONFIGURATION

Reconguring Bendix EC-80 ABS ECUs

Reconguring a Bendix EC‑80 ABS controller may be

carried out by using the Blink Code Switch or by using a hand‑held or PC‑based diagnostic tool.

Note: During the reconguration process, and independently from any reconguration being carried out by the technician,

standard ECUs automatically check the J1939 serial link and communicate with other vehicle modules. In particular, if the serial link shows that the vehicle has a retarder device

present, the ECU will congure itself to communicate with

the retarder device for improved ABS performance. For example, if the ECU detects the presence of a retarder

disable relay during a reconguration, it will congure

itself to control the relay to disable the retarding device as needed.

Reconguring Bendix EC-80 ATC ECUs

As with non‑ATC ECUs, the Bendix EC‑80 ATC ECU also

carries out — independently from any reconguration

being carried out by the technician — an automatic check of the J1939 serial link and communicates with other vehicle modules. This includes checking for ATC and retarder disable relay operation. In addition, Bendix EC‑80 ATC controllers will determine the number of wheel

speed sensors and PMVs installed and congure itself

accordingly.

6S/5M Conguration

Bendix EC-80 ATC controllers will congure for 6S/5M

operation when a reconguration event is initiated and the

ECU detects that an additional axle PMV is wired as follows:

PMV Connector ECU Connector

Hold Right Additional Axle Hold

Release Left Additional Axle Release

Common Right Additional Axle Common

See 6S/5M System Schematic (page 37) for details.

Reconguration Using the Blink Code Switch

The reconguration procedure is the same for ATC and

non‑ATC ECUs. With ignition power removed from the Bendix EC‑80 controller, depress the blink code switch. After the ignition power is activated, depress and release

the switch seven times to initiate a reconguration.

Diagnostic Tool

A reconguration event may be initiated using a hand-held

or PC‑based diagnostic tool to communicate with the ECU over the SAE J1939 diagnostic link.

Troubleshooting: General

Read and follow the General Safety Guidelines on page two (2) of this document.

REMOVING THE BENDIX® EC-80™ CONTROLLER ASSEMBLY

1. Turn vehicle ignition off.

2. Remove as much contamination as possible prior to disconnecting air lines and electrical connections.

3. Note the ECU assembly mounting position on the vehicle.

4. Disconnect the electrical connectors from the ECU.

5. Remove and retain the mounting bolts that secure the ECU.

INSTALLING A NEW BENDIX

EC-80™ CONTROLLER

When replacing the Bendix® EC-80™ controller, verify that the unit you are installing has the correct default settings. Failure to do so could result in a loss of features, such as ATC and PLC, or noncompliance with U.S. regulations such as FMVSS 121. It is recommended to use only the correct replacement part

number. However, most conguration settings can

be altered using the Bendix® ACom® ABS Diagnostic Software program.

Verify correct operation of the Bendix EC‑80 controller system and indicator lamps prior to putting the vehicle back into service. Towing vehicles manufactured after March 1, 2001 must support the trailer ABS indicator lamp located on the dash.

For further information, contact either the vehicle manufacturer, Bendix® or your local authorized Bendix® dealer.

1. Position and secure the Bendix EC‑80 controller in the original mounting orientation using the mounting bolts retained during removal. When mounting the unit in

the cab, use no more torque than is necessary to rmly

secure the ECU into position. Over‑tightening the mounting hardware can cause damage to the Bendix EC‑80 controller.

2. Reconnect the electrical connectors to the ECU.

3. Apply power and monitor the Bendix EC‑80 controller power‑up sequence to verify proper system operation.

See Troubleshooting: Wiring section beginning on page 32 for more information on wiring harnesses.

Troubleshooting: Blink Codes and Diagnostic Modes

ECU DIAGNOSTICS

The Bendix® EC‑80™ controller contains self‑testing diagnostic circuitry that continuously checks for the normal operation of internal components and circuitry, as well as external ABS components and wiring.

Active Diagnostic Trouble Codes

When an erroneous system condition is detected, the Bendix EC‑80 controller:

1. Illuminates the appropriate indicator lamp(s) and disengages part or all of the ABS and ATC functions. (See pages 8-9.)

2. Places the appropriate trouble code information in the ECU memory.

3. Communicates the appropriate trouble code information over the serial communications diagnostic link as required. Hand‑held or PC‑based diagnostic tools attach to the vehicle diagnostic connector, typically located on or under the dash (See Figure 7).

FIGURE 7 - TYPICAL VEHICLE DIAGNOSTIC CONNECTOR LOCATION (J1939)

BLINK CODES

Blink codes allow a technician to troubleshoot ABS problems without using a hand‑held or PC‑based diagnostic tool. Instead, information about the ABS system is communicated by the ECU using the ABS indicator lamp to display sequences of blinks.

Note: The ECU will not enter the diagnostic blink code mode if the wheel speed sensors show that the vehicle is in motion. If the ECU is in the diagnostic blink code mode and then detects vehicle motion, it will exit the blink code mode.

In addition, by operating the blink code switch as described below, one of several diagnostic modes can be entered. See Diagnostic Modes below.

Blink Code Switch Activation

When activating the blink code switch:

1. Wait at least two seconds after “ignition on.” (Except when

entering Reconguration Mode - see Reconguration

section on page 11)

2. For the ECU to recognize that the switch is activated “on,” the technician must press for at least 0.1 seconds, but less than 5 seconds. (If the switch is held for more than 5 seconds, the ECU will register a malfunctioning switch.)

3. Pauses between pressing the switch when a sequence is required, (e.g. when changing mode) must not be longer than 2 seconds.

4. After a pause of 3.5 seconds, the ECU will begin responding with output information blinks. See Figure 10 for an example.

FIGURE 8 - EXAMPLE OF BLINK CODE MESSAGE

Blink Code Timing

The ECU responds with a sequence of blink codes. The overall blink code response from the ECU is called a “message.” Each message includes, depending on the mode selected by the technician, a sequence of one or more groups of blinks. Simply record the number of blinks for each sequence and then use the troubleshooting index on page 18 for active or inactive trouble codes. Once you have located the code, you will be directed to the page that provides the applicable troubleshooting information.

NOTE:

1. Blink sequences illuminate the ABS indicator lamp for half a second, with half‑second pauses between them.

2. Pauses between blink code digits are 1.5 seconds.

3. Pauses between blink code messages are 2.5 seconds.

4. The lamp remains on for ve (5) seconds at the end of

messages.

See Figure 8 for an example showing the message: 2,1 followed by 2,2.

Once the ABS indicator lamp begins displaying a sequence of codes, it continues until all blink code messages have been displayed and then returns to the normal operating mode. During this time, the ECU will ignore any additional blink code switch activation.

All trouble codes, with the exception of voltage and J1939 trouble codes, will remain in an active state for the remainder of the power cycle.

Voltage trouble codes will clear automatically when the voltage returns within the required limits. All ABS functions will be re‑engaged.

J1939 trouble codes will clear automatically when communications are re‑established.

DIAGNOSTIC MODES

In order to communicate with the ECU, the controller has several modes that the technician can select, allowing information to be retrieved, or other ECU functions to be accessed.

Diagnostic Modes

To enter the various diagnostic modes:

No. of

Times to

Press the

Blink Code

Switch

1 Active Diagnostic Trouble Code (DTC) retrieval

2 Inactive DTC retrieval

3 Clear active DTCs

4 System conguration check

5 Dynamometer Test Mode

7* Recongure ECU

* To enter the Reconguration Mode, the switch must be held

in before the application of ignition power. Once the power is supplied, the switch is released and then pressed seven times.

CHART 3 - DIAGNOSTIC MODES

Active Diagnostic Trouble Code Mode

For troubleshooting, typically the active and inactive Diagnostic Trouble Retrieval Modes are used. The technician presses the blink code switch once and the ABS

indicator lamp ashes a rst group of two codes, and if

there are more trouble codes recorded, this is followed by a second set of codes, etc. (See page 18 for a directory of these codes.) All active trouble codes may also be retrieved using a hand‑held or PC‑based diagnostic tool, such as the Bendix® ACom® Diagnostics software.

To clear active DTCs (as problems are xed), simply clear

(or “self‑heal”) by removing and re‑applying ignition power. The only exception is for wheel speed sensor trouble codes, which clear when power is removed, re‑applied, and the ECU detects valid wheel speed from all wheel speed sensors. Alternately, codes may be cleared by pressing the diagnostic blink code switch three (3) times (to enter the Clear Active Diagnostic Trouble Code Mode) or by using a hand‑held or PC‑based diagnostic tool. Hand‑held or PC‑based diagnostic tools are able to clear wheel speed sensor trouble codes without the vehicle being driven.

System Mode Entered

Inactive Diagnostic Trouble Code Mode

The ECU stores past trouble codes and comments (such

as conguration changes) in its memory. This record is

commonly referred to as “event history.” When an active trouble code is cleared, the ECU stores it in the event history memory as an inactive trouble code.

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