Service Manual
Trucks
Group 28
Engine Control Module (ECM), Diagnostic Trouble Code
(DTC), Guide
2010 Emissions
CHU, CXU, GU, TD
PV776-88961816
Foreword
The descriptions and service procedures contained in this manual are based on designs and methods studies carried out up to March 2010.
The products are under continuous development. Vehicles and components produced after the above date may therefore have different specifications and repair methods. When this is believed to have a significant bearing on this manual, supplementary service bulletins will be issued to cover the changes.
The new edition of this manual will update the changes.
In service procedures where the title incorporates an operation number, this is a reference to a Labor Code (Standard Time).
Service procedures which do not include an operation number in the title are for general information and no reference is made to a Labor Code (Standard Time).
Each section of this manual contains specific safety information and warnings which must be reviewed before performing any procedure. If a printed copy of a procedure is made, be sure to also make a printed copy of the safety information and warnings that relate to that procedure. The following levels of observations, cautions and warnings are used in this Service Documentation:
Note: Indicates a procedure, practice, or condition that must be followed in order to have the vehicle or component function in the manner intended.
Caution: Indicates an unsafe practice where damage to the product could occur.
Warning: Indicates an unsafe practice where personal injury or severe damage to the product could occur.
Danger: Indicates an unsafe practice where serious personal injury or death could occur.
Mack Trucks, Inc.
Greensboro, NC USA
Order number: PV776-88961816
Repl:
©2010 Mack Trucks, Inc., Greensboro, NC USA
All rights reserved. No part of this publication may be reproduced, stored in retrieval system, or transmitted in any forms by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of Mack Trucks, Inc.
USA40713
Contents |
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Design and Function.................................................................................................................... |
3 |
Engine Control Module (ECM)...................................................................................................... |
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On Board Diagnostic (OBD) Monitors............................................................................................ |
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Troubleshooting .......................................................................................................................... |
22 |
Engine Control Module (ECM) Diagnostic Trouble Codes (DTCs) ..................................................... |
22 |
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Group 28 |
Engine Control Module (ECM) |
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Design and Function
Engine Control Module (ECM)
The manufacturer scan tool is the preferred tool for performing diagnostic work. Contact your local dealer for more information or visit “www.premiumtechtool.com”.
Note: Theuseofascantoolisnecessarytoperformdiagnostic work as well as clearing of any diagnostic trouble codes (DTCs). DTC(s) can no longer be cleared using the vehicles instrument cluster digital display and stalk switch control.
System Overview
Six electronic control units (ECUs) are used; the engine control module (ECM), instrument control module (ICM), Vehicle Electronic Control Unit (VECU), transmission control module (TCM), the gear selector control module (GSCM) and the aftertreatment control module (ACM). Together, these modules operate and communicate through the SAE J1939 (CAN
1) data link to control a variety of engine and vehicle cab functions. The ECM controls such things as fuel timing and delivery, fan operation, engine protection functions, engine brake operation, the exhaust gas recirculation (EGR) valve and the turbocharger nozzle. The VECU controls cruise control functions, accessory relay controls and idle shutdown functions. The ICM primarily displays operational parameters and communicates these to the other ECUs. All have the capability to communicate over the SAE J1587 data link primarily for programming, diagnostics and data reporting.
In addition to their control functions, the modules have on board diagnostic (OBD) capabilities. The OBD is designed to detect faults or abnormal conditions that are not within normal operating parameters. When the system detects a fault or abnormal condition, the fault will be logged in one or both of the modules’ memory, the vehicle operator will be advised that a fault has occurred by illumination a malfunction indicator lamp (MIL) and a message in the driver information display, if equipped. The module may initiate the engine shutdown procedure if the system determines that the fault could damage the engine.
In some situations when a fault is detected, the system will enter a "derate" mode. The derate mode allows continued vehicle operation but the system may substitute a sensor or signal value that may result in reduced performance. In some instances, the system will continue to function but
engine power may be limited to protect the engine and vehicle. Diagnostic trouble codes (DTCs) logged in the system memory can later be read, to aid in diagnosing the problem using a diagnostic computer or through the instrument cluster display, if equipped. When diagnosing an intermittent DTC or condition, it may be necessary to use a scan tool connected to the Serial Communication Port.
The use of a scan tool is necessary to perform diagnostic work as well as clearing of any diagnostic trouble codes (DTCs). DTC(s) can no longer be cleared using the vehicles instrument cluster digital display and stalk switch control. Additional data and diagnostic tests are available when a scan tool is connected to the Serial Communication Port.
For diagnostic software, contact your local dealer.
The ECM is a microprocessor based controller programmed to perform fuel injection quantity and timing control, diagnostic fault logging, and to broadcast data to other ECUs. The fuel quantity and injection timing to each cylinder is precisely controlled to obtain optimal fuel economy and reduced exhaust emissions in all driving situations.
The ECM controls the operation of the injectors, engine brake solenoid, EGR valve, turbocharger nozzle position, and cooling fan clutch based on inputs from many sensors and information received over the data links from other ECUs.
The VECU and ECM are dependent on each other to perform their specific control functions. In addition to switch and sensor data, the broadcast of data between modules also includes various calculations and conclusions that each module has developed, based on the input information it has received.
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On Board Diagnostic (OBD) Monitors
System Electronic Control Unit (ECU) Overview
The engine control module (ECM) monitors and models (using physical principles) engine parameters to monitor the engine system’s performance in real time. This is performed to aid the ECM with its self diagnostic capabilities. Many sensors are used for input to the emission control system.
The system contains the following “emission critical” ECUs that are monitored;
•Engine Control Module (ECM)
•Vehicle Electronic Control Unit (VECU)
•Aftertreatment Control Module (ACM)
•Aftertreatment Nitrogen Oxides (NOx) Sensors
•Engine Variable Geometry Turbocharger (VGT) Smart Remote Actuator (SRA)
These ECUs all communicate with the ECM via data links. The VECU communicates across the SAE J1939 (CAN1) data link while the others use the SAE J1939-7 (CAN2) data link.
The OBD systems use SAE J1939 data link protocol for communication with scan tools but, MACK trucks still are capable of communicating via the SAE J1587 data link for diagnostics. The use of a scan tool is necessary to perform diagnostic work as well as clearing of any diagnostic trouble codes (DTCs). DTC(s) can no longer be cleared using the vehicles instrument cluster digital display and stalk switch control.
There are other ECUs such as the Instrument Control Module (ICM), Transmission Control Module (TCM) and Anti-lock Brake System (ABS) Module that provide data to the emission control system or the diagnostic system but are not “emission critical”.
Malfunction Indicator Lamp (MIL), Description and Location
A MIL located in the instrument cluster. This amber colored lamp is used to inform the driver that a “emission critical” malfunction signal has occurred.
W2036007
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Systems Monitoring Information
Section Content
•“Accelerator Pedal Position (APP) Sensor, Overview”, page 6
•“Active/intrusive Injection (Aftertreatment Hydrocarbon Doser Clogging)”, page 6
•“Aftertreatment Diesel Exhaust Fluid (DEF) Feedback Control”, page 6
•“Aftertreatment Diesel Exhaust Fluid (DEF) Quality ”, page 6
•“Aftertreatment Diesel Particulate Filter (DPF)”, page 6
•“AftertreatmentDieselParticulateFilter(DPF)Regeneration Frequency”, page 6
•“Aftertreatment Diesel Particulate Filter (DPF) Incomplete Regeneration ”, page 6
•“AftertreatmentDieselParticulateFilter(DPF)Regeneration Feedback Control”, page 6
•“Aftertreatment Fuel System, Rationality Monitors”, page 7
•“Aftertreatment Non-Methane Hydro Carbons (NMHC) Catalyst”, page 7
•“Aftertreatment Nitrogen Oxides (NOx) Sensor(s) Overview”, page 7
•“Aftertreatment Selective Catalytic Reduction (SCR)”, page 7
•“Aftertreatment Selective Catalytic Reduction (SCR) Conversion Efficiency”, page 7
•“Ambient Air Temperature (AAT) Sensor, Overview”, page 7
•“Charge Air Cooler (CAC)”, page 8
•“Combined Monitoring”, page 8
•“Crankcase Ventilation”, page 8
•“Crankcase Ventilation Diagnostic Function”, page 8
•“Engine Control Module (ECM), Rationality Monitors”, page 8
•“Engine Coolant Temperature (ECT) Sensor Overview”, page 8
•“Exhaust Gas Recirculation (EGR)”, page 8
•“Exhaust Gas Recirculation (EGR) Low Flow”, page 8
•“Exhaust Gas Recirculation (EGR) High Flow”, page 8
•“Exhaust Gas Recirculation (EGR) Slow Response”, page 9
•“Exhaust Gas Recirculation (EGR) Feedback Control”, page 9
•“Exhaust Gas Recirculation (EGR) Cooler Performance”, page 9
•“Exotherm”, page 9
•“Filtering Performance”, page 9
•“Fuel System”, page 9
•“Idle Speed, Rationality Monitors”, page 9
•“Intake Manifold Pressure (IMP) Control System”, page 9
•“Misfire”, page 10
•“Missing Substrate”, page 10
•“Over-boost”, page 10
•“Parking Brake Switch, Overview”, page 10
•“Power Take-off (PTO) Enable Switch, Overview”, page 10
•“SAE J1939 (CAN1) Data Link, Overview”, page 10
•“Thermostat Monitor”, page 10
•“Time/Date Overview”, page 10
•“Variable Geometry Turbocharger (VGT) Feedback Control”, page 10
•“Vehicle Speed Sensor (VSS), Overview”, page 11
•“Under-boost”, page 11
•“Variable Geometry Turbocharger (VGT) Slow Response”, page 11
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Accelerator Pedal Position (APP) Sensor, Overview
The APP sensor input is an analog voltage signal proportional to the pedal position that is read by the vehicle electronic control unit (VECU). The angular position of the pedal is divided in three different areas used for fault detection and/or recovery. The value that is transmitted under normal
conditions (value of 0 - 100%), is directly proportional to the pedal’s angular position. The physical accelerator assembly also supports a digital DC voltage (On/Off) generated by an idle validation (IV) switch that is also powered by the same regulated reference voltage source.
Active/intrusive Injection (Aftertreatment Hydrocarbon Doser Clogging)
This diagnostic is based on the checking the aftertreatment diesel particulate filter (DPF) intake temperature during aftertreatment DPF active parked regeneration cycles. If the aftertreatment DPF intake temperature does not reach a
minimum regeneration temperature within a specified time then the aftertreatment hydrocarbon doser is considered to be clogged.
Aftertreatment Diesel Exhaust Fluid (DEF) Feedback Control
The aftertreatment DEF control consists of a feedforward control together with a feedback control. The feedforward control value is how much urea that must be injected in order
to obtain the demanded nitrogen oxides (NOx) conversion efficiency. The feedback controls the ammonia (NH3) buffer in the aftertreatment selective catalytic reduction (SCR).
Aftertreatment Diesel Exhaust Fluid (DEF) Quality
Aftertreatment DEF quality is evaluated and determined through conversion efficiency. If the aftertreatment SCR system efficiency is below the specified limit, a fault is reported.
Aftertreatment Diesel Particulate Filter (DPF)
The aftertreatment DPF collects particulate and soot in a ceramic wall-flow substrate. The strategy to manage the accumulation of soot is to take advantage of natural
aftertreatment DPF passive regeneration whenever possible,
and to invoke an operating mode that enhances aftertreatment DPF passive regeneration when necessary. Aftertreatment DPF active regeneration is performed using an aftertreatment hydrocarbon doser.
Aftertreatment Diesel Particulate Filter (DPF) Regeneration Frequency
This function detects if the aftertreatment DPF regeneration frequency increases to a level that it would cause the non-methane hydro carbon (NMHC) emissions to exceed the legal limitation or if the frequency exceeds the design
requirements. If the number of aftertreatment DPF regenerations are above the threshold at the end of the time period a fault is reported.
Aftertreatment Diesel Particulate Filter (DPF) Incomplete Regeneration
The aftertreatment DPF regeneration strategy is to reduce the soot level in the DPF using passive regeneration. However, if the driving conditions do not enable enough exhaust heat for passive regeneration to keep up with the soot loading an active parked aftertreatment DPF regeneration will be required.
An interrupted parked aftertreatement DPF regeneration is detected by this function. This is not a fault mode but handled by the aftertreatment system. If the ratio between the uncompleted and completed regenerations is above the specified limit, a fault is reported.
Aftertreatment Diesel Particulate Filter (DPF) Regeneration Feedback Control
This function monitors the particulate matter regeneration feedback control and detects:
•If the system fails to begin feedback control
•If a failure or deterioration causes open loop
•If the feedback control has used up all of the allowed adjustment
When the aftertreatment hydrocarbon doser is used, the feedback control is monitored for a saturated controller or a saturated actuator. A saturated controller or actuator means that all allowed adjustment has been used up. The monitors detect a malfunction if the controller is saturated more than a given percentage of the time and the target temperature can
not be reached or if the actuator is saturated more than a given percentage of the time.
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Aftertreatment Fuel System, Rationality Monitors
The aftertreatment fuel system consists of a aftertreatment fuel shutoff valve, a separate aftertreatment hydrocarbon doser (injector), and an aftertreatment fuel pressure sensor. The aftertreatment fuel shutoff valve diagnostic function look at the aftertreatment fuel pressure when the valve is opened and closed. When conditions are proper for the diagnostic, the function requests an opening of the aftertreatment fuel shutoff valve in order to pressurize the aftertreatment fuel system.
This action should increase system pressure. When the aftertreatment fuel shutoff valve is closed the system pressure should decrease since the valve has an internal drain pipe that constantly depressurizes the system. For more information about these components refer to “Aftertreatment Fuel Pressure Sensor, Circuit Monitors”, page 16, “Aftertreatment Fuel Shutoff Valve, Circuit Monitors”, page 16 or “Aftertreatment Hydrocarbon Doser, Circuit Monitors”, page 16.
Aftertreatment Non-Methane Hydro Carbons (NMHC) Catalyst
To detect when the hydrocarbon conversion fails in the aftertreatment diesel oxidation catalyst (DOC), the temperature reaction at the aftertreatment DOC outlet is monitored when fuel is injected in the exhaust. The amount of hydrocarbon supplied by the aftertreatment hydrocarbon doser will determine the expected increase in temperature after the aftertreatment DOC. The aftertreatment hydrocarbon doser
injection rate (duty cycle) is monitored and used to calculate whether there should be a corresponding heat reaction. Once it has reached an acceptable accumulated duty cycle the expected temperature difference can be calculated. This difference should then be above a certain limit if the hydrocarbon conversion was achieved.
Aftertreatment Nitrogen Oxides (NOx) Sensor(s) Overview
The NOx sensors consist of:
•Housing holding the sensing element.
•An electronic control unit (ECU), interfacing the sensor and the engine control module (ECM).
•A wire, electrically connecting the sensing element with the ECU.
There are two aftertreatment NOx sensors, one before and one after the aftertreatment selective catalytic reduction (SCR) catalyst. The aftertreatment NOx sensor before and after SCR catalyst have unique CAN identification numbers hence can not be swapped. The sensor before the SCR catalyst monitors the engine out NOx level. The sensor after SCR monitors system out NOx level.
Aftertreatment NOx sensor diagnostics monitor the sensors signal quality and performance. The purpose of this function is to detect the following,
•Bad signal quality
•Removed sensor
•Missing signal
Circuit integrity of the aftertreatment NOx sensor is checked by the sensor itself and the status is transmitted to the engine control module (ECM) over the CAN data link. The following can be transmitted,
•open circuit
•high voltage
•circuit low or high
Aftertreatment Selective Catalytic Reduction (SCR)
The aftertreatment SCR system is a catalyst system that is used to reduce exhaust Nitrogen Oxides (NOx) emissions. This reduction is performed by injecting diesel exhaust fluid (DEF) (a urea solution) into the exhaust fumes prior to the aftertreatment SCR catalyst. A chemical process performed by aftertreatment SCR catalyst and DEF, converts NOx to
nitrogen oxide (NO) and water (H2O). The aftertreatment control module (ACM) is used to control the aftertreatment SCR components and relays system information to the Engine Control Module (ECM). The ECM controls the overall system function.
Aftertreatment Selective Catalytic Reduction (SCR) Conversion Efficiency
The aftertreatment SCR catalyst diagnosis calculates the low temperature performance of the aftertreatment SCR system and compares it to the performance when the catalyst is warm enough to reach high nitrogen oxides (NOx) conversion.
This is based on the premise that a deteriorated catalyst can be considered as a catalyst with less volume. The volume is critical to reach the low temperature performance of the aftertreatment SCR system.
Ambient Air Temperature (AAT) Sensor, Overview
The AAT sensor is an analog input that is read by the instrument cluster electronic control unit. The instrument cluster processes the raw signal and transmits the AAT value on the SAE J1939 data link. The vehicle electronic control unit (VECU) receives the AAT value and based on certain vehicle conditions the value is adjusted. The VECU then transmits
the AAT value back on the SAE J1939 data link where it is received by the engine control module (ECM).
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Charge Air Cooler (CAC)
The nominal CAC efficiency is a map based on mass air flow (MAF) and ambient air temperature (AAT). The method to evaluate the CAC efficiency is to compare a nominal CAC
efficiency with one calculated based on the exhaust gas recirculation (EGR) and the intake air temperature (IAT) sensor along with their corresponding mass flows.
Combined Monitoring
Cylinder balancing function is used to detect fuel system pressure, quantity and timing fault. By processing the tooth times cylinder balancing detects if the combustion power contribution from one or several cylinders is too week or too strong and need to be compensated to get even combustion
power from all cylinders. The compensation is calculated at the lower engine speed (RPM) and torque regions during warm engine where the impact from each combustion becomes most visible. If the compensation becomes too high or too low fault is detected.
Crankcase Ventilation
The crankcase pressure (CCP) depends on the blow-by flow and the under pressure generated by the separator. Blow-by gases come mainly from the combustion when exhaust gas passes the piston rings. A malfunctioning of the valve guides,
or the turbocharger can also contribute. The blow-by gases consist of exhaust gases mixed with oil. A high speed rotating separator is used to expel engine oil from these gases.
Crankcase Ventilation Diagnostic Function
When the high speed separator enabling conditions exist, the minimum value of the difference between crankcase and barometric pressure (BARO) during a time period is stored.
The system performs high speed and low speed evaluations of the separator to conclude if the system is tight.
Engine Control Module (ECM), Rationality Monitors
If electrical power to the ECM is lost or very low, the ECM will stop to functioning and the engine will stop. Other electronic
control units (ECUs) on the SAE J1939 (CAN1) data link will indicate that data from the ECU is missing.
Engine Coolant Temperature (ECT) Sensor Overview
The ECT sensor is monitored for rationality at key ON by comparing the ECT with the other engine temperature sensors (engine oil temperature (EOT) and engine turbocharger compressor outlet temperature). Using this comparison the following conclusions may be made when a problem occurs:
•Unable to reach Closed loop/Feedback enable Temperature (covered by thermostat warmed up temperature)
•Time to reach Closed loop/Feedback enable Temperature (covered by thermostat warmed up temperature)
•Stuck in a range below the highest minimum Enable temperature
•Stuck in a Range Above the Lowest maximum Enable temperature - Rationality Check
When the engine is used, the three temperatures are not the same and depending on how fast the engine is restarted normal differences will be found. When these differences and the ambient air temperature (AAT) exceeds a limit, the fault limits are adjusted in order to allow these differences.
Exhaust Gas Recirculation (EGR)
US2010 emission level MACK engines use EGR to enhance engine out Nitrogen Oxides (NOx) control. EGR flow is managed using an EGR valve and a Variable Geometry Turbocharger (VGT) nozzle position. These actuator settings are based on open loop settings established to achieve
desired burned fraction rates. These settings can be modified in a closed loop burned fraction mode by feedback from a combustion property model. The EGR system is diagnosed by monitoring the burned fraction whenever the engine enters burned fraction closed loop mode.
Exhaust Gas Recirculation (EGR) Low Flow
This function monitors the reduction of EGR flow in the EGR system, i.e. too low EGR mass flow compared with demand. It is activated when the engine enters the burned fraction mode
with minimum demand for BF and the engine speed/torque is in a range where EGR flow measurements and BF calculations have sufficient accuracy.
Exhaust Gas Recirculation (EGR) High Flow
This function diagnoses too much EGR in the system, i.e. too high EGR mass flow compared with the demand. This function handles positive deviations when EGR closed loop control is active. When closed loop EGR control is entered, an initial difference between measured burned fraction and burned
fraction demand might exist. Due to the fact that some time is needed for adaptation, not all the difference is taken into account.
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Exhaust Gas Recirculation (EGR) Slow Response
As described in “Exhaust Gas Recirculation (EGR) Low Flow”, page 8 and “Exhaust Gas Recirculation (EGR) High Flow”, page 8 , the deviation between the demanded and measured
burned fraction are monitored when EGR closed loop control is active. Slow response is detected when the deviation (high/low) above the threshold is detected.
Exhaust Gas Recirculation (EGR) Feedback Control
This function detects: |
• If feedback control mode is inhibited. |
• If any of the feedback control loops are not achieved. |
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Exhaust Gas Recirculation (EGR) Cooler Performance
This function uses an equation based off of engine turbocharger turbine intake temperature, EGR temperature and the engine coolant temperature (ECT), to calculate cooler
efficiency. The calculated efficiency is deemed too low if it is below a certain constant limit.
Exotherm
Exotherm, exothermic or exothermal all refer to a chemical change that is accompanied by a great release of heat. The aftertreatment heating function uses the aftertreatment hydrocarbon doser, to heat up the exhaust system for parked aftertreatment diesel particulate filter (DPF) regeneration. When the aftertreatment hydrocarbon doser is used the hydrocarbons (HC) create an exotherm in the aftertreatment
diesel oxidation catalyst (DOC). The aftertreatment hydrocarbon doser injection rate (duty cycle) is monitored and used to calculate whether there should be a corresponding exotherm. A starting temperature value is set when the aftertreatment hydrocarbon doser starts to inject fuel. As soon as the model says that exotherm should occur, the difference is calculated to identify whether it has occurred.
Filtering Performance
A malfunction of the aftertreatment diesel particulate filter (DPF) can be detected by analysing the pressure drop over the aftertreatment DPF. During the aftertreatment DPF evaluation,
the lower and upper limiting values of the measured pressure drop are calculated. If the pressure drop is lower or higher than expected a fault indication occurs.
Fuel System
The D13L engine uses a unit injector system (as opposed to a rail injector system) to inject fuel in the cylinders. The unit injectors are not equipped with any pressure sensors and therefore it is not possible to measure fuel pressure. Diagnostics of the fuel injection system is done using the
crankshaft position (CKP) sensor. The flywheel of the engine has slots machined at 6 degree intervals around its circumference. Three gaps where two slots are missing, are equally spaced around its circumference also. The three gaps are used to identify the next cylinder in firing order.
Idle Speed, Rationality Monitors
The target idle engine speed (RPM) and fuel injection quantity are monitored in the idle control system. The diagnosis monitors compare the measured engine speed (RPM) (averaged over each engine cycle) and target idle engine speed (RPM). The accumulated difference is averaged over a number of revolutions. If the averaged difference is above or
below the defined fault limits, diagnostic trouble codes (DTCs) will be set for high fault and for low fault, respectively.
The same holds true for the fuel quantity. The accumulated fuel value is averaged over a number of revolutions. If the averaged difference is above, DTCs will be set for high fault.
Intake Manifold Pressure (IMP) Control System
A IMP sensor located in the intake manifold is used to measure IMP. The IMP system is monitored by comparing target/estimated IMP with actual measured pressure during certain engine speed (RPM) or load.
The target/estimated IMP is continuously calculated based on engine speed and fuel angle and adjusted for the influence of variable geometry turbocharger (VGT) nozzle position, exhaust gas recirculation (EGR) position and barometric pressure (BARO).
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Misfire
The misfire monitor is disabled during Power Take Off (PTO) operation. It is active during positive brake torque, idle, and high idle. Engine misfire events are monitored by measuring tooth times on the crank wheel that indicates combustion acceleration in each cylinder. It is also possible to compare the previous acceleration contribution on each cylinder in order to examine if there has been a misfire or not.
After monitoring misfire events during idle conditions for the accumulation of less than 15 seconds, the percentage of misfire is evaluated. If the percentage of misfire exceeds the threshold limit, the misfire diagnostic trouble code (DTC) will be set for the fault.
Missing Substrate
The aftertreatment diesel particulate filter (DPF) is backpressure monitored. This monitoring is used to determine
whether the aftertreatment DPF is either clogged, missing or significantly cracked.
Over-boost
If the measured intake manifold pressure (IMP) is over the deviation upper limit then the high boost average calculation is positive. If the measured IMP is below the deviation upper limit
then the high boost integration is negative. If the integrated value exceeds the maximum limit a fault for high IMP is set.
Parking Brake Switch, Overview
The parking brake switch is a pressure switch that is physically connected to the vehicle’s parking brake pneumatic circuit and is used to determine if the parking brake is applied or released. The parking brake switch signal is received by the vehicle electronic control unit (VECU). When the vehicle’s parking
brake is applied a ground signal is applied to the input and the VECU acknowledges the parking brake as being applied. The parking brake switch signal is provided to the engine control module (ECM) via the SAE J1939 data link.
Power Take-off (PTO) Enable Switch, Overview
The PTO enable switch is an input that is read by the vehicle electronic control unit (VECU). When 12V is applied to the input the VECU acknowledges the PTO function is being
commanded on. The PTO Enable switch signal is provided to the engine control module (ECM) from the VECU by via the SAE J1939 data link.
SAE J1939 (CAN1) Data Link, Overview
Communication between the electronic control units (ECUs) is performed via the vehicle’s SAE J1939 (CAN1) data link and is accessible for diagnostics through the vehicle’s SAE J1939-13 data link connector (DLC). This data link is the main powertrain communication bus.
Diagnostic trouble codes (DTCs) are set for this data link when an ECU is found to not be communicating or recognized on the data link (off bus mode) or when there is an abnormal rate of occurrence of errors on the data link.
Thermostat Monitor
This feature monitors and compares the engine coolant temperature (ECT), engine speed (RPM), engine torque, fan
speed and ambient air temperature (AAT) to conclude when the thermostat may be stuck open or closed.
Time/Date Overview
The time and date is calculated from an internal clock within the instrument cluster. The internal clock is backed up by an internal battery therefore the time and date is retained even when vehicle battery supply to the instrument cluster is
removed. The time and date signal is provided to the engine control module (ECM) from the instrument cluster via the SAE J1939 data link.
Variable Geometry Turbocharger (VGT) Feedback Control
This function detects:
If any of the feedback control loops are not achieved.
If feedback control mode is inhibited.
If the actuators have used up all the adjustment allowed when in feedback mode.
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Vehicle Speed Sensor (VSS), Overview
The vehicle road speed is calculated by the vehicle electronic control unit (VECU). The source for calculating vehicle road speed can be derived from multiple sources depending on vehicle equipment. Some trucks may use a dedicated speed
sensor (which may be inductive or hall effect type) and some may use the transmission output shaft speed (OSS) sensor signal which is communicated across the SAE J1939 data link.
Under-boost
If the measured intake manifold pressure (IMP) is less than the deviation lower limit then the low boost average calculation is negative. If the measured IMP is above the deviation lower
limit then the low boost integration is positive. If the integrated value becomes less than the minimum limit a fault for low IMP is set.
Variable Geometry Turbocharger (VGT) Slow Response
The VGT actuator reports a fault to the engine control module (ECM) when it has detected that the VGT nozzle is not moving, or if it has not been able to close the set-point error to acceptable limits.
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Sensor and Component Information
Section Content
• “AcceleratorPedalPosition(APP)Sensor,CircuitMonitors”, |
• “Aftertreatment Nitrogen Oxides (NOx) Sensors, Circuit |
page 14 |
Monitors”, page 16 |
• “Accelerator Pedal Position (APP) Sensor, Rationality |
• “Aftertreatment Nitrogen Oxides (NOx) Sensors, Rationality |
Monitors”, page 14 |
Monitors”, page 16 |
• “Aftertreatment Control Module (ACM), Rationality |
• “Ambient Air Temperature (AAT) Sensor, Circuit Monitors”, |
Monitors”, page 14 |
page 16 |
• “Aftertreatment Control Module (ACM) 5 Volt Supply 1, |
• “Ambient Air Temperature (AAT) Sensor, Rationality |
Circuit Monitors”, page 14 |
Monitors”, page 16 |
• “Aftertreatment Control Module (ACM) 5 Volt Supply 2, |
• “Barometric Pressure (Baro) Sensor Circuit Monitoring”, |
Circuit Monitors”, page 14 |
page 16 |
• “Aftertreatment Control Module (ACM) Actuator Supply |
• “Barometric Pressure (BARO) Sensor Rationality Monitors”, |
Voltage 1, Circuit Monitors”, page 14 |
page 16 |
• “Aftertreatment Control Module (ACM) Actuator Supply |
• “Camshaft Position (CMP) Sensor, Circuit Monitors”, page |
Voltage 2, Circuit Monitors”, page 14 |
17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Dosing Valve, |
• “Camshaft Position (CMP) Sensor, Rationality Monitors”, |
Circuit Monitors”, page 14 |
page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Dosing Valve, |
• “Crankcase Pressure (CCP) Sensor, Circuit Monitors”, |
Rationality Monitors”, page 14 |
page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Pressure |
• “Crankcase Pressure (CCP) Sensor, Rationality Monitors”, |
Sensor, Circuit Monitors”, page 14 |
page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Pressure |
• “Crankshaft Position (CKP) Sensor, Circuit Monitors”, page |
Sensor, Rationality Monitors”, page 15 |
17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Pump, Circuit |
• “Crankshaft Position (CKP) Sensor, Rationality Monitors”, |
Monitors”, page 15 |
page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Pump, |
• “Engine Control Module (ECM) 5 Volt Supply A, Circuit |
Rationality Monitors”, page 15 |
Monitors”, page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Return Value, |
• “Engine Control Module (ECM) 5 Volt Supply B, Circuit |
Circuit Monitors”, page 15 |
Monitors”, page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Return Valve, |
• “Engine Coolant Temperature (ECT) Sensor, Circuit |
Rationality Monitors”, page 15 |
Monitors”, page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Tank Heater |
• “Engine Coolant Temperature (ECT) Sensor, Rationality |
Valve, Circuit Monitors”, page 15 |
Monitors”, page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Tank Heater |
• “Engine Exhaust Gas Recirculation (EGR), Differential |
Valve, Rationality Monitors”, page 15 |
Pressure Sensor, Circuit Monitoring”, page 17 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Tank |
• “Engine Exhaust Gas Recirculation (EGR), Differential |
Temperature Sensor, Circuit Monitors”, page 15 |
Pressure Sensor, Rationality Monitors”, page 18 |
• “Aftertreatment Diesel Exhaust Fluid (DEF) Tank |
• “Engine Exhaust Gas Recirculation (EGR) Temperature |
Temperature Sensor, Rationality Monitors”, page 15 |
Sensor, Circuit Monitors”, page 18 |
• “Aftertreatment Diesel Particulate Filter (DPF), Differential |
• “Engine Exhaust Gas Recirculation (EGR) Temperature |
Pressure Sensor, Circuit Monitoring”, page 15 |
Sensor, Rationality Monitors”, page 18 |
• “Aftertreatement Diesel Particulate Filter (DPF) Differential |
• “Engine Exhaust Gas Temperature (EGT) Sensors, Circuit |
Pressure Sensor, Rationality Monitors”, page 16 |
Monitors”, page 18 |
• “Aftertreatment Fuel Pressure Sensor, Circuit Monitors”, |
|
page 16 |
|
• “Aftertreatment Fuel Shutoff Valve, Circuit Monitors”, page |
|
16 |
|
• “Aftertreatment Hydrocarbon Doser, Circuit Monitors”, page |
|
16 |
|
12
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
•“Engine Exhaust Gas Temperature (EGT) Sensors, Rationality Monitors”, page 18
•“Engine Turbocharger Compressor Bypass Valve Solenoid, Circuit Monitors”, page 18
•“Engine Turbocharger Compressor Bypass Valve Solenoid, Rationality Monitors”, page 18
•“Engine Turbocharger Compressor Outlet Temperature Sensor, Circuit Monitors”, page 18
•“Engine Turbocharger Compressor Outlet Temperature Sensor, Rationality Monitors”, page 18
•“Engine Turbocharger Speed Sensor, Circuit Monitors”, page 19
•“Engine Turbocharger Speed Sensor, Rationality Monitors”, page 19
•“Engine Variable Geometry Turbocharger (VGT) Actuator Position, Circuit Monitors”, page 19
•“Engine Variable Geometry Turbocharger (VGT) Actuator Position, Rationality Monitors”, page 19
•“Exhaust Gas Recirculation (EGR) Valve Actuator, Circuit Monitors”, page 19
•“Exhaust Gas Recirculation (EGR) Valve Actuator, Rationality Monitors”, page 19
•“Fan, Circuit Monitors”, page 19
•“Fan, Rationality Monitors”, page 19
•“Injector, Circuit Monitors”, page 20
•“Intake Air Temperature (IAT) Sensor, Circuit Monitors”, page 20
•“Intake Air Temperature (IAT) Sensor, Rationality Monitors”, page 20
•“Intake Manifold Pressure (IMP) Sensor Circuit Monitoring”, page 20
•“Intake Manifold Pressure (IMP) Sensor Rationality Monitors”, page 20
•“Injector, Rationality Monitors”, page 20
•“Parking Brake Switch, Circuit Monitors”, page 20
•“Parking Brake Switch, Rationality Monitors”, page 20
•“Power Take-off (PTO) Enable Switch, Circuit Monitors”, page 20
•“Power Take-off (PTO) Enable Switch, Rationality Monitors”, page 20
•“SAE J1939 (CAN1) Data Link, Circuit Monitors”, page 21
•“SAE J1939 (CAN1) Data Link, Rationality Monitors”, page 21
•“SAE J1939 (CAN2) Data Link, Overview”, page 21
•“SAE J1939 (CAN2) Data Link, Circuit Monitors”, page 21
•“SAE J1939 (CAN2) Data Link, Rationality Monitors”, page 21
•“Time/Date, Circuit Monitoring”, page 21
•“Time/Date, Rationality Monitoring”, page 21
•“Vehicle Speed Sensor (VSS), Circuit Monitors”, page 21
•“Vehicle Speed Sensor (VSS), Rationality Monitors”, page 21
13
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
Accelerator Pedal Position (APP) Sensor, Circuit Monitors
Both signals are continuously monitored (sampled) by the vehicle electronic control unit (VECU) at 50 ms intervals to detect any distortion or disruption of these signals. Signals detected as invalid for a period extending over 500 ms trigger active faults that are broadcast by the VECU. The APP sensor circuits are monitored to identify the following:
•Circuit open
•Circuit low
•Circuit high
Accelerator Pedal Position (APP) Sensor, Rationality Monitors
The vehicle electronic control unit (VECU) simultaneously reads the APP sensor and the idle validation (IV) switch values and performing a plausibility to verify sensor performance.
Aftertreatment Control Module (ACM), Rationality Monitors
If electrical power to the ACM is lost or very low the ACM will |
diagnostic trouble code (DTC) indicating SAE J1939 data link |
stop functioning. Aftertreatment diesel exhaust fluid (DEF) |
(subdatalinkCAN2)communicationsfromtheACMismissing. |
dosing will stop. The engine control module (ECM) will log a |
|
Aftertreatment Control Module (ACM) 5 Volt Supply 1, Circuit Monitors
The ACM 5 volt supply “1” circuit is monitored to identify the |
• Circuit high |
|
following: |
When either fault is detected the supply is disabled. |
|
• Circuit low |
||
|
Aftertreatment Control Module (ACM) 5 Volt Supply 2, Circuit Monitors
The ACM 5 volt supply“2” circuit is monitored to identify the following:
• Circuit low
• Circuit high
When circuit high or circuit low faults are detected the supply is disabled.
Aftertreatment Control Module (ACM) Actuator Supply Voltage 1, Circuit Monitors
The ACM actuator supply voltage “1” circuit is monitored to identify the following:
•Circuit open
•Circuit low
• Circuit high
When circuit high or circuit low faults are detected the supply is disabled.
Aftertreatment Control Module (ACM) Actuator Supply Voltage 2, Circuit Monitors
The ACM actuator supply voltage “2” circuit is monitored to identify the following:
•Circuit open
•Circuit low
• Circuit high
When circuit high or circuit low faults are detected the supply is disabled.
Aftertreatment Diesel Exhaust Fluid (DEF) Dosing Valve, Circuit Monitors
The aftertreatment DEF dosing valve circuits are monitored |
• |
Circuit low |
to identify the following: |
• |
Circuit high |
• Circuit open |
|
|
Aftertreatment Diesel Exhaust Fluid (DEF) Dosing Valve, Rationality Monitors
The aftertreatment DEF pump control value is monitored when the aftertreatment DEF dosing valve duty cycle has been above a predetermined threshold, for a short duration. If the
control value is too low a diagnostic trouble code (DTC) is set. This indicates a clogged dosing valve or blocked aftertreatment DEF line.
Aftertreatment Diesel Exhaust Fluid (DEF) Pressure Sensor, Circuit Monitors
The aftertreatment DEF pressure sensor circuits are monitored to identify the following:
• Circuit open/circuit high
•Out of range low
•Out of range high
•Circuit low
14
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
Aftertreatment Diesel Exhaust Fluid (DEF) Pressure Sensor, Rationality Monitors
During pressure build up (aftertreatment DEF pump runs with maximum speed with no dosing) if selective catalytic reduction (SCR) system pressure stays low for a preset duration, a diagnostic trouble code (DTC) is set. Pressure is
also evaluated during normal operation with aftertreatment DEF pump turned off. If the pressure is too high for a preset duration a DTC is set
Aftertreatment Diesel Exhaust Fluid (DEF) Pump, Circuit Monitors
The aftertreatment DEF pump circuits are monitored to identify the following:
• Circuit open
•Circuit low
•Circuit high
•Battery voltage
Aftertreatment Diesel Exhaust Fluid (DEF) Pump, Rationality Monitors
The aftertreatment DEF pump gets a signal for the required pump speed from the aftertreatment control module (ACM). The pump has internal diagnosis which evaluates the pump speed quality. If the pump speed deviates from commanded speed for some time a diagnostic trouble code (DTC) is set.
The aftertreatment DEF return value is monitored during specific conditions to identify if a leak in the system is present. A DTC is set if a leak condition is identified. The leak can be invisible (internal to the pump or valve) or visible (aftertreatment DEF lines or connections).
Aftertreatment Diesel Exhaust Fluid (DEF) Return Value, Circuit Monitors
The aftertreatment DEF return valve circuits are monitored |
• |
Circuit low |
to identify the following: |
• |
Circuit high |
• Circuit open |
|
|
Aftertreatment Diesel Exhaust Fluid (DEF) Return Valve, Rationality Monitors
During reverse DEF flow conditions on a pressurized selective catalytic reduction (SCR) system, pressure drop is evaluated. If DEF pressure drop is too low, the aftertreatment DEF return
valve is considered to have a mechanical fault (blocked or stuck) and a diagnostic trouble code (DTC) is set.
Aftertreatment Diesel Exhaust Fluid (DEF) Tank Heater Valve, Circuit Monitors
The aftertreatment DEF tank heater valve circuits are |
• |
Circuit low |
monitored to identify the following: |
• |
Circuit high |
• Circuit open |
|
|
Aftertreatment Diesel Exhaust Fluid (DEF) Tank Heater Valve, Rationality Monitors
Aftertreatment DEF tank heater valve diagnostics evaluates if tank heater is taking place, when demanded. A comparison of an initial aftertreatment DEF tank temperature without heating and then a tank temperature with aftertreatment DEF
tank heater valve open for some duration is performed. If the increase in temperature is smaller than the threshold, a diagnostic trouble code (DTC) is set.
Aftertreatment Diesel Exhaust Fluid (DEF) Tank Temperature Sensor, Circuit Monitors
The aftertreatment DEF tank temperature sensor circuits are monitored to identify the following:
• Circuit open/circuit high
•Out of range low
•Out of range high
•Circuit low
Aftertreatment Diesel Exhaust Fluid (DEF) Tank Temperature Sensor, Rationality Monitors
Aftertreatement DEF tank temperature is checked for high frequency oscillations with high amplitude that is so large that is physically impossible for a temperature to achieve. A fault is set when this behavior is observed. Aftertreatement DEF tank temperature diagnostics is also evaluating if the
aftertreatement DEF temperature is too high and will activate reverse flow (to protect aftertreatment selective catalytic reduction (SCR) system components) and a timer is started. If the temperature stays high for a short duration, a fault is set.
Aftertreatment Diesel Particulate Filter (DPF), Differential Pressure Sensor, Circuit Monitoring
The aftertreatment DPF differential pressure sensor circuits |
• |
Circuit high |
are monitored to identify the following: |
• |
Circuit open |
• Circuit low |
|
|
15
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
Aftertreatement Diesel Particulate Filter (DPF) Differential Pressure Sensor, Rationality Monitors
The evaluation of the pressure-drop sensor is carried out as follows. When the pressure model indicates a low pressure the sensor should also show a low pressure otherwise there is a (large) positive offset fault. Combining this with a check that
the sensor shows high values when the model is high gives a sensor stuck check. The second step can also find (large) negative offset faults.
Aftertreatment Fuel Pressure Sensor, Circuit Monitors
The aftertreatment fuel pressure sensor circuits are monitored to identify the following:
•Circuit open
•Out of range low
•Out of range high
•Circuit low
•Circuit high
Aftertreatment Fuel Shutoff Valve, Circuit Monitors
The aftertreatment fuel shutoff valve circuits are monitored to identify the following:
• Circuit open
•Circuit low
•Circuit high
Aftertreatment Hydrocarbon Doser, Circuit Monitors
The aftertreatment hydrocarbon doser circuits are monitored to identify the following:
• Circuit open
•Circuit low
•Circuit high
Aftertreatment Nitrogen Oxides (NOx) Sensors, Circuit Monitors
The NOx sensors circuits are monitored to identify the |
• |
high voltage |
following: |
• |
circuit low or high |
• open circuit |
|
|
Aftertreatment Nitrogen Oxides (NOx) Sensors, Rationality Monitors
There are two different monitors which diagnose aftertreatment NOx sensor rationality. One compares the aftertreatment intake NOx sensor value to a calculated engine NOx output value. This is only perform within a given set of predetermined conditions. If the NOx sensor value is not deemed within range, a faulty is set.
The other compares theaftertreatment intake NOx sensor value to the aftertreatment outlet NOx sensor value to determine rationality. This is only perform within a given set of predetermined conditions. If either of the aftertreatment NOx sensor values are deemed not plausible, a diagnostic faulty code (DTC) is set.
Ambient Air Temperature (AAT) Sensor, Circuit Monitors
The AAT sensor circuits are monitored by the instrument cluster module to identify the following:
• Current below normal or open
• Current above normal or grounded
None of the AAT sensor circuits are monitored by the ECM or the VECU.
Ambient Air Temperature (AAT) Sensor, Rationality Monitors
Plausibility of the sensor value is determined by comparing the AAT with the intake air temperature (IAT).
Barometric Pressure (Baro) Sensor Circuit Monitoring
The BARO sensor circuits are monitored to identify the |
• |
following: |
• |
• Circuit low |
|
Circuit high
Circuit open
Barometric Pressure (BARO) Sensor Rationality Monitors
The BARO sensor, intake manifold pressure (IMP) sensor, and crankcase pressure (CCP) sensor should show the same pressure when engine speed (RPM) and torque is low. The diagnosis calculates the difference between:
•BARO and CCP
•IMP and CCP
These comparisons are used to identify defects.
• BARO and IMP
16
Group 28 On Board Diagnostic (OBD) Monitors
Camshaft Position (CMP) Sensor, Circuit Monitors
The CMP sensor circuits are monitored to identify the following: |
• |
Circuit low |
• Circuit open |
• |
Circuit high |
Camshaft Position (CMP) Sensor, Rationality Monitors
The CMP sensor is monitored by comparing it’s output signal to the output signal of the crankshaft position (CMP) sensor. This comparison is used to identify abnormal CKP and CMP
sensor frequency as well as camshaft to crankshaft phasing (calculated top dead center (TDC). Abnormal sensor frequency and shaft phasing angle will set faults.
Crankcase Pressure (CCP) Sensor, Circuit Monitors
The CCP circuits are monitored to identify the following: |
• |
Out of range high |
|
• |
Circuit open |
• |
Circuit low |
• |
Out of range low |
• |
Circuit high |
Crankcase Pressure (CCP) Sensor, Rationality Monitors
The BARO sensor, intake manifold pressure (IMP) sensor, and crankcase pressure (CCP) sensor should show the same pressure when engine speed (RPM) and torque is low. The diagnosis calculates the difference between:
•
•
•
BARO and IMP
BARO and CCP
IMP and CCP
Crankshaft Position (CKP) Sensor, Circuit Monitors
The CKP sensor circuits are monitored to identify the following: |
• |
Circuit low |
• Circuit open |
• |
Circuit high |
Crankshaft Position (CKP) Sensor, Rationality Monitors
The CKP sensor is monitored by comparing it’s output signal to the output signal of the camshaft position (CMP) sensor. This comparison is used to identify abnormal CKP and CMP
sensor frequency as well as camshaft to crankshaft phasing (calculated top dead center (TDC). Abnormal sensor frequency and shaft phasing angle will set faults.
Engine Control Module (ECM) 5 Volt Supply A, Circuit Monitors
The ECM 5 volt supply “A” circuit is monitored to identify the |
• |
Circuit high |
||
following: |
When either fault is detected the supply is disabled. |
|||
• |
Circuit low |
|||
|
|
|||
Engine Control Module (ECM) 5 Volt Supply B, Circuit Monitors |
||||
The ECM 5 volt supply “B” circuit is monitored to identify the |
• |
Circuit high |
||
following: |
When either fault is detected the supply is disabled. |
|||
• |
Circuit low |
|||
|
|
|||
Engine Coolant Temperature (ECT) Sensor, Circuit Monitors |
||||
The ECT sensor circuits are monitored to identify the following: |
• |
Circuit low |
||
• |
Circuit open |
• |
Circuit high |
|
• |
Out of range low |
|
|
|
Engine Coolant Temperature (ECT) Sensor, Rationality Monitors
The ECT sensor is monitored for rationality at key ON by comparing the ECT with engine oil temperature (EOT) and engine turbocharger compressor outlet temperature. For
more information refer to “Engine Coolant Temperature (ECT) Sensor Overview”, page 8 .
Engine Exhaust Gas Recirculation (EGR), Differential Pressure Sensor, Circuit Monitoring
The engine EGR differential pressure sensor circuits are |
• Circuit open |
|
monitored to identify the following: |
|
|
• |
Circuit low |
|
• |
Circuit high |
|
17
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
Engine Exhaust Gas Recirculation (EGR), Differential Pressure Sensor, Rationality Monitors
Engine EGR differential pressure is estimated based on engine speed (RPM) or torque and corrected for variable geometry turbocharger (VGT) position, EGR valve position, intake manifold pressure (IMP) and barometric pressure (BARO). This estimated engine EGR differential pressure is compared with actual measured pressure. This comparison is used to
identify if the engine EGR differential pressure sensor is faulty. During certain conditions the engine EGR differential pressure should be zero. The engine EGR differential pressure sensor is also monitored during these conditions to verify that the engine EGR is closing as necessary as well as to verify proper engine EGR differential pressure sensor operation.
Engine Exhaust Gas Recirculation (EGR) Temperature Sensor, Circuit Monitors
The engine EGR temperature sensor circuits are monitored to identify the following:
•Circuit open
•Out of range low
•Out of range high
•Circuit low
•Circuit high
Engine Exhaust Gas Recirculation (EGR) Temperature Sensor, Rationality Monitors
For information about the engine EGR temperature sensor rationality refer to “Intake Air Temperature (IAT) Sensor, Rationality Monitors”, page 20.
Engine Exhaust Gas Temperature (EGT) Sensors, Circuit Monitors
The exhaust system is equipped with the following three engine EGT sensors:
1Engine EGT sensor
2Aftertreatment diesel particulate filter (DPF) intake temperature sensor
3Aftertreatment DPF outlet temperature sensor
The engine EGT sensor circuits are monitored to identify the following:
•Circuit open
•Out of range low
•Out of range high
•Circuit low
•Circuit high
Engine Exhaust Gas Temperature (EGT) Sensors, Rationality Monitors
There are two independent tests that can evaluate temperature sensor plausibility in the exhaust system. One is performed while stationary and the other is performed at cold start. Each sensors output value is used to compare against the other
sensor values. This in turn is used to determine the plausibility of the sensors. If the temperatures received by any of the sensors is deemed to be out of range, a plausibility fault is set.
Engine Turbocharger Compressor Bypass Valve Solenoid, Circuit Monitors
The engine turbocharger compressor bypass valve solenoid |
• |
Circuit low |
circuits are monitored to identify the following: |
• |
Circuit high |
• Circuit open |
|
|
Engine Turbocharger Compressor Bypass Valve Solenoid, Rationality Monitors
The engine turbocharger compressor bypass valve solenoid fault detection is performed during the phase where the valve
is opened, the intake manifold pressure (IMP) is monitored and compared to the maximum allowed.
Engine Turbocharger Compressor Outlet Temperature Sensor, Circuit Monitors
The engine turbocharger compressor outlet temperature sensor circuits are monitored to identify the following:
•Circuit open
•Out of range low
•Out of range high
•Circuit low
•Circuit high
Engine Turbocharger Compressor Outlet Temperature Sensor, Rationality Monitors
The engine turbocharger compressor outlet temperature sensor, is monitored for rationality by comparing the sensor output value against an estimated temperature based on ambient air temperature (AAT), intake manifold pressure (IMP),
barometric pressure (BARO) and a calculated efficiency of the turbocharger.
18
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
Engine Turbocharger Speed Sensor, Circuit Monitors
The engine turbocharger speed sensor circuits are monitored to identify the following:
•Circuit open
•Out of range low
•Out of range high
•Circuit low
•Circuit high
Engine Turbocharger Speed Sensor, Rationality Monitors
An engine turbocharger speed sensor test is run within a set of conditions to evaluate the speed sensor output value. The engine turbocharger speed sensor value is compared to
a calculated speed value that is based on intake manifold pressure (IMP). If the sensor output value is deemed out of range a fault is set.
Engine Variable Geometry Turbocharger (VGT) Actuator Position, Circuit Monitors
The engine VGT actuator position position actuator circuits are |
• |
Circuit low |
monitored to identify the following: |
• |
Circuit high |
• Circuit open |
|
|
Engine Variable Geometry Turbocharger (VGT) Actuator Position, Rationality Monitors
The engine VGT has a smart actuator position that is checked within Smart Remote Actuator (SRA) unit. Engine VGT
position is then communicated to engine control module (ECM) via the SAE J1939 (CAN) data link.
Exhaust Gas Recirculation (EGR) Valve Actuator, Circuit Monitors
The EGR valve actuator circuits are monitored to identify the |
• |
Circuit low |
following: |
• |
Circuit high |
• Circuit open |
|
|
Exhaust Gas Recirculation (EGR) Valve Actuator, Rationality Monitors
When EGR valve is commanded to be closed, the EGR differential pressure sensor is monitored and expects no pressure difference between upstream and downstream of EGR venture. A fault occurs when differential pressure greater than a fault limit due to a stuck-open EGR valve or a leaking
EGR valve is detected for a period of time. A stuck-closed EGR valve can be detected if the difference from the actual burned fraction to the demanded burned fraction is lower than a fault limit for a period of time. There is no EGR Valve position feedback.
Fan, Circuit Monitors
The fan circuits are monitored to identify the following:
•Circuit open
•Circuit low
•Circuit high
Electrical power is supplied to the fan drive from the chassis. Circuit monitoring is performed on the low side drive. The fan circuitry is such, that when the low side drive is opened the fan will be on. Closing the path to ground causes the fan to turn off. Since the low side is monitored the checks are only performed under certain conditions:
•Open circuit monitoring is only performed when the fan is ON (open circuit low). The open circuit fault detects when power is not supplied to the high side of the fan drive
•Circuit low monitoring is only performed when the fan is ON (open circuit low). The circuit low fault detects when the low side control line is shorted to ground
•Circuit high monitoring is only performed when the fan is OFF (closed circuit low). The circuit high fault detects an over-current condition on the low side control line. If this over-current condition is detected the drive is disabled (fan ON) until the key is cycled
Some fans also have a fan speed sensor. If the fan is equipped with a speed sensor circuit high is also supported. This diagnostic is used for any electrical cause of a missing signal. If the fan does not support a speed sensor this circuit monitor is not supported.
Fan, Rationality Monitors
Fan speed is calculated from the commanded percent engagement, the engine speed and the fan drive ratio. If a fan speed sensor is present the sensor speed signal is sent.
19
Group 28 On Board Diagnostic (OBD) Monitors
Injector, Circuit Monitors
The injector circuits are monitored to identify the following: |
• |
Circuit low |
|
• |
Circuit open |
• |
Circuit high |
Intake Air Temperature (IAT) Sensor, Circuit Monitors |
|
||
The IAT sensor circuits are monitored to identify the following: |
• |
Circuit low |
|
• |
Circuit open |
• |
Circuit high |
• |
Out of range low |
|
|
Intake Air Temperature (IAT) Sensor, Rationality Monitors
The IAT sensor is used to calculate engine charge air cooler (CAC) ambient air temperature (AAT). The CAC AAT can be calculated in the two following ways,
•Using engine exhaust exhaust gas recirculation (EGR) temperature and IAT with their corresponding mass flow rates.
•Using AAT, engine turbocharger compressor outlet temperature and the mass air flow (MAF) rate.
If there is a mismatch in these two estimated temperatures it is concluded that the most probably cause is on of the temperature sensors. The system then rationalizes which sensor is faulty.
Intake Manifold Pressure (IMP) Sensor Circuit Monitoring
The IMP sensor circuits are monitored to identify the following: |
• |
Out of range high |
|
• |
Circuit open |
• |
Circuit low |
• |
Out of range low |
• |
Circuit high |
Intake Manifold Pressure (IMP) Sensor Rationality Monitors
The IMP sensor, BARO sensor, and crankcase pressure (CCP) sensor should show the same pressure when engine speed and torque is low. The diagnosis calculates the difference between:
•BARO and IMP
•BARO and CCP
•IMP and CCP
These comparisons are used to identify defects.
Injector, Rationality Monitors
For injector rationality monitor information refer to “Fuel System”, page 9 .
Parking Brake Switch, Circuit Monitors
The vehicle electronic control unit (VECU) does not support comprehensive circuit monitoring on parking brake switch.
Parking Brake Switch, Rationality Monitors
The vehicle electronic control unit (VECU) does not support rationality monitors on the parking brake switch.
Power Take-off (PTO) Enable Switch, Circuit Monitors
The vehicle electronic control unit (VECU) does not support comprehensive circuit monitoring for the PTO enable switch input. However, based on the type of failure modes to the circuit the PTO operation will be or become non-functional. The failure mode behaviors are defined as:
•Short to Ground – A short circuit to ground will result in a non-functional PTO operation.
•Short to Battery – A short circuit to battery voltage will not have an immediate affect to the PTO operation, but will result in a non-functional PTO operation after exiting the PTO function or during the next VECU power down/up sequence (I.e. Cycling of the ignition key switch).
•Open Circuit – An open will result in a non-functional PTO operation.
Power Take-off (PTO) Enable Switch, Rationality Monitors
The vehicle electronic control unit (VECU) does not support rationality monitors on the PTO enable switch.
20
Group 28 |
On Board Diagnostic (OBD) Monitors |
|
|
SAE J1939 (CAN1) Data Link, Circuit Monitors
Error detection of the SAE J1939 (CAN1) data link is performed by multiple electronic control units (ECUs). An ECU detecting an error condition signals this by transmitting an error flag.
There are 5 types of error detections:
• Bit error
SAE J1939 (CAN1) Data Link, Rationality Monitors
Rationality monitors do not exist for the SAE J1939 (CAN1) data link.
•
•
•
•
Stuff error
Cyclic Redundancy Code (CRC) error
Form error
Acknowledgement error
SAE J1939 (CAN2) Data Link, Overview
The SAE J1939 (CAN2) data link is a sub-data link that communicatesinformationdirectlytotheenginecontrolmodule (ECM). There’s no direct communication to other electronic control units (ECUs) residing on the on the SAE J1939 (CAN1) data link. Information that is sent across the CAN2 data link
can be shared on the CAN1 data link via the ECM. Diagnostic trouble codes (DTCs) are set when an ECU is found to not be communicating or recognized on the data link (off bus mode) or when there is an abnormal rate of occurrence of errors on the data link.
SAE J1939 (CAN2) Data Link, Circuit Monitors
Error detection of the SAE J1939 (CAN2) data link is performed by multiple electronic control units (ECUs). An ECU detecting an error condition signals this by transmitting an error flag.
There are 5 types of error detections:
• Bit error
SAE J1939 (CAN2) Data Link, Rationality Monitors
Rationality monitors do not exist for the SAE J1939 (CAN2) data link.
Time/Date, Circuit Monitoring
The instrument cluster does not support comprehensive circuit monitoring for the Time/Date.
•
•
•
•
Stuff error
Cyclic Redundancy Code (CRC) error
Form error
Acknowledgement error
Time/Date, Rationality Monitoring
The engine control module (ECM) does support rational monitoring by comparing time and date from instrument
cluster. Soak time is based on engine cooling down using temperatures before and after soak.
Vehicle Speed Sensor (VSS), Circuit Monitors
The comprehensive circuit monitors are supported by the vehicle electronic control unit (VECU) and are determined by the vehicle road speed source. When a dedicated speed sensor is used, electrical error detection is supported. When
Vehicle Speed Sensor (VSS), Rationality Monitors
Error detection is performed by comparing another source of vehicle speed information to the calculated vehicle road speed. At zero vehicle road speed an error is generated when the comparison vehicle speed source (ABS/EBS) is higher than a specified limit. When the vehicle road speed is greater than zero the difference between the calculated vehicle road speed and the comparison vehicle speed source (ABS/EBS) is not allowed to be greater than a specified value or a fault is registered.
the transmission output shaft speed (OSS) sensor is used via the SAE J1939 data link, the diagnostics are based on a communication timeout and receiving “error indicator” flagged from the transmitting electronic control unit (ECU).
21
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
Troubleshooting
Engine Control Module (ECM) Diagnostic Trouble Codes (DTCs)
The manufacturer scan tool is the preferred tool for performing diagnostic work. Contact your local dealer for more information or visit “www.premiumtechtool.com”.
Note: Theuseofascantoolisnecessarytoperformdiagnostic work as well as clearing of any diagnostic trouble codes (DTCs). DTC(s) can no longer be cleared using the vehicles instrument cluster digital display and stalk switch control .
SAE J1939 Data Link Communication
The electronic control units (ECUs) that communicate on the SAE J1939 data link, communicate according to the SAE J1587 standard. The diagnostic trouble codes (DTCs) set by the ECUs contain information that is described by the following abbreviations.
SA |
Source Address: |
|
Identification of a control module. |
SPN |
Suspect Parameter Number: |
|
Identification of a parameter (value). |
FMI |
Failure Mode Identifier: |
|
Identification of fault types. |
22
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
SAE J1939 FMI Table
FMI |
SAE Text |
|
|
0 |
Data valid but above normal operational range - Most severe level |
|
|
1 |
Data valid but below normal operational range - Most severe level |
|
|
2 |
Data erratic, intermittent or incorrect |
|
|
3 |
Voltage above normal, or shorted to high source |
|
|
4 |
Voltage below normal, or shorted to low source |
|
|
5 |
Current below normal or open circuit |
|
|
6 |
Current above normal or grounded circuit |
|
|
7 |
Mechanical system not responding or out of adjustment |
|
|
8 |
Abnormal frequency or pulse width or period |
|
|
9 |
Abnormal update rate |
|
|
10 |
Abnormal rate of change |
|
|
11 |
Root cause not known |
|
|
12 |
Bad intelligent device or component |
|
|
13 |
Out of calibration |
|
|
14 |
Special instructions |
|
|
15 |
Data valid but above normal operating range - Least severe level |
|
|
16 |
Data valid but above normal operating range - Moderately severe level |
|
|
17 |
Data valid but below normal operating range - Least severe level |
|
|
18 |
Data valid but below normal operating range - Moderately severe level |
|
|
19 |
Received network data in error |
|
|
20 |
Reserved for SAE assignment |
|
|
21 |
Reserved for SAE assignment |
|
|
22 |
Reserved for SAE assignment |
|
|
23 |
Reserved for SAE assignment |
|
|
24 |
Reserved for SAE assignment |
|
|
25 |
Reserved for SAE assignment |
|
|
26 |
Reserved for SAE assignment |
|
|
27 |
Reserved for SAE assignment |
|
|
28 |
Reserved for SAE assignment |
|
|
29 |
Reserved for SAE assignment |
|
|
30 |
Reserved for SAE assignment |
|
|
31 |
Condition exists |
|
|
23
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
SAE J1587 Data Link Communication
The electronic control units (ECUs) also communicate on the SAE J1587 data link. These ECUs communicate according to the SAE J1587 standard. The standard has been extended with MACK’s supplement (PPID, PSID). The diagnostic trouble codes (DTCs) set by the ECUs contain information that is described by the following abbreviations.
MID |
Message Identification Description: |
|
Identification of a control module. |
PID |
Parameter Identification Description: |
|
Identification of a parameter (value). |
PPID |
Proprietary Parameter Identification |
|
Description Mack: |
|
Unique identification of a parameter (value). |
SID |
Subsystem Identification Description: |
|
Identification of a component. |
PSID |
Proprietary Subsystem Identification |
|
Description Mack: |
|
Unique identification of a component. |
FMI |
Failure Mode Identifier: |
|
Identification of fault types. |
SAE J1587 FMI Table
FMI |
SAE Text |
|
|
0 |
Data valid, but above the normal working range |
|
|
1 |
Data valid, but below the normal working range |
|
|
2 |
Intermittent or incorrect data |
|
|
3 |
Abnormally high voltage or short circuit to higher voltage |
|
|
4 |
Abnormally low voltage or short circuit to lower voltage |
|
|
5 |
Abnormally low current or open circuit |
|
|
6 |
Abnormally high current or short circuit to ground |
|
|
7 |
Incorrect response from a mechanical system |
|
|
8 |
Abnormal frequency |
|
|
9 |
Abnormal update rate |
|
|
10 |
Abnormally strong vibrations |
|
|
11 |
Non-identifiable fault |
|
|
12 |
Faulty module or component |
|
|
13 |
Calibration values outside limits |
|
|
14 |
Special instructions |
|
|
15 |
Reserved for future use |
|
|
24
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
Diagnostic Trouble Code (DTC) Content
SPN 0–500
•“ECM SPN 84, Wheel-Based Vehicle Speed – MID 128 PID 84”, page 31
•“ECM SPN 91, Accelerator Pedal Position 1 – MID 128 PID 91”, page 31
•“ECM SPN 94, Engine Fuel Delivery Pressure – MID 128 PID 94”, page 31
•“ECM SPN 97, Water in Fuel Indicator – MID 128 PID 97”, page 32
•“ECM SPN 98, Engine Oil Level – MID 128 PID 98”, page 33
•“ECM SPN 100, Engine Oil Pressure – MID 128 PID 100”, page 33
•“ECM SPN 102, Engine Intake Manifold 1 Pressure – MID 128 PID 102”, page 34
•“ECM SPN 103, Engine Turbocharger 1 Speed – MID 128 PID 103”, page 35
•“ECM SPN 105, Engine Intake Manifold 1 Temperature – MID 128 PID 105”, page 36
•“ECM SPN 108, Barometric Pressure – MID 128 PID 108”, page 36
•“ECM SPN 110, Engine Coolant Temperature – MID 128 PID 110”, page 37
•“ECM SPN 111, Engine Coolant Level – MID 128 PID 111”, page 38
•“ECM SPN 153, Engine High Resolution Crankcase Pressure – MID 128 PID 153/PSID 23”, page 39
•“ECM SPN 158, Keyswitch Battery Potential – MID 128 PID 158/PSID 124”, page 39
•“ECM SPN 171, Ambient Air Temperature – MID 128 PID 171”, page 40
•“ECM SPN 173, Engine Exhaust Gas Temperature (EGT) – MID 128 PID 173 ”, page 42
•“ECM SPN 175, Engine Oil Temperature 1 – MID 128 PID 175”, page 43
•“ECM SPN 177, Transmission Oil Temperature – MID 128 PID 177”, page 44
25
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
•“ECM SPN 188, Engine Speed At Idle, Point 1 (Engine Configurations) – MID 128 PID 188”, page 44
•“ECM SPN 190, Engine Speed – MID 128 PID 190”, page 44
•“ECM SPN 228, Speed Sensor Calibration – MID 128 PID 228”, page 45
•“ECM SPN 237, Vehicle Identification Number – MID 128 PSID 161/162”, page 45
•“ECM SPN 245, Total Vehicle Distance – MID 128 PID 245”, page 45
•
•
•
“ECM SPN 251, Time – MID 128 PID 251”, page 46
“ECM SPN 252, Date – MID 128 PID 252”, page 47
“ECM SPN 411, Engine Exhaust Gas Recirculation Differential Pressure – MID 128 PID 411”, page 47
• “ECM SPN 412, Engine Exhaust Gas Recirculation Temperature – MID 128 PID 412”, page 48
SPN 500–999
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
“ECM SPN 558, Accelerator Pedal 1 Idle Validation Switch
– MID 128 SID 230”, page 49
“ECM SPN 626, Intake Air Heater (IAH) Relay – MID 128 PID 45”, page 50
“ECM SPN 628, Program Memory – MID 128 SID 240”, page 50
“ECM SPN 629, Electronic Control Unit (ECU) 1 – MID 128 SID 254”, page 51
“ECM SPN 630, Calibration Memory – MID 128 SID 253”, page 51
“ECM SPN 631, Calibration Module – MID 128 PSID 77/PSID 124”, page 52
“ECM SPN 633, Engine Fuel Actuator 1 Control Command
– MID 128 SID 18”, page 52
“ECM SPN 636, Camshaft Position Sensor (CMP) – MID 128 SID 21”, page 53
“ECM SPN 637, Crankshaft Position Sensor (CKP) – MID 128 SID 22”, page 54
“ECM SPN 639, SAE J1939 Data Link 1 – MID 128 SID 231”, page 55
“ECM SPN 641, Engine Variable Geometry Turbocharger (VGT) Actuator 1 – MID 128 SID 27”, page 55
“ECM SPN 642, Engine Variable Geometry Turbocharger (VGT) Actuator 2 – MID 128 PPID 89”, page 56
“ECM SPN 647, Engine Fan Clutch Output Device Driver – MID 128 SID 33”, page 56
“ECM SPN 651, Engine Injector Cylinder 1 – MID 128 SID 1”, page 57
“ECM SPN 652, Engine Injector Cylinder 2 – MID 128 SID 2”, page 58
26
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
•“ECM SPN 653, Engine Injector Cylinder 3 – MID 128 SID 3”, page 58
•“ECM SPN 654, Engine Injector Cylinder 4 – MID 128 SID 4”, page 59
•“ECM SPN 655, Engine Injector Cylinder 5 – MID 128 SID 5”, page 60
•“ECM SPN 656, Engine Injector Cylinder 6 – MID 128 SID 6”, page 61
•“ECM SPN 677, Engine Starter Motor Relay – MID 128 SID 39”, page 61
•“ECM SPN 729, Intake Air Heater (IAH) 1 – MID 128 SID 70”, page 62
•“ECM SPN 730, Intake Air Heater (IAH) 2 – MID 128 SID 71”, page 62
•“ECM SPN 975, Estimated Percent Fan Speed – (MID 128 PID 26)”, page 63
SPN 1000–1999
•“ECM SPN 1072, Engine Compression Brake Output #1 – MID 128 PPID 122”, page 64
•“ECM SPN 1127, Engine Turbocharger Intake Manifold Pressure (IMP) – MID 128 PSID 98”, page 65
•“ECM SPN 1136, Engine Control Module (ECM) Temperature – MID 128 PPID 55”, page 66
•“ECM SPN 1198, Anti–theft Random Number – MID 128 PID 224”, page 66
•“ECM SPN 1231, SAE J1939 Data Link 2 – MID 128 PSID 229/232”, page 67
•“ECM SPN 1265, Engine Piston Cooling Oil Pressure Actuator – MID 128 SID 85”, page 67
•“ECM SPN 1322, Engine Misfire for Multiple Cylinders – MID 128 PSID 27”, page 68
•“ECM SPN 1659, Engine Coolant System Thermostat – MID 128 PSID 109”, page 68
•“ECM SPN 1675, Engine Starter Mode – MID 128 SID 39”, page 68
•“ECM SPN 1677, Aftertreatment DPF Auxiliary Heater Mode – MID 128 PSID 25”, page 69
•“ECM SPN 1761, Aftertreatment Diesel Exhaust Fluid (DEF) Tank Level – PPID 278”, page 69
27
Group 28
Engine Control Module (ECM) Diagnostic Trouble
Codes (DTCs)
SPN 2000–2999
•“ECM SPN 2003, Transmission Control Module (TCM) Status – MID 128 PSID 205”, page 70
•“ECM SPN 2017, Cruise Control Status – MID 128 PID 85”, page 70
•“ECM SPN 2029, Invalid or Missing Data from Vehicle ECU
– MID 128 PSID 201”, page 70
•“ECM SPN 2629, Engine Turbocharger Compressor Outlet Temperature – MID 128 PID 404”, page 71
•“ECM SPN 2659, Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate – MID 128 PPID 35”, page 71
•“ECM SPN 2791, Engine Exhaust Gas Recirculation (EGR) Valve Control – MID 128 SID 146”, page 72
•“ECM SPN 2836, Battery Potential/Switched Voltage – MID 128 PSID 49”, page 72
28
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