Prevost Saint-Nicolas, Quebec, Canada Service Bulletin Buses Date Group No. Release Page 6.2010 364 00 1(12) Vehicle Electronic Control Unit (VECU) MID 144, Diagnostic Trouble Code (DTC), Guide Vehicle Electronic Control Unit (VECU) MID 144, Diagnostic Trouble Code (DTC), Guide Contents MID 144 Vehicle Electronic Control Unit (VECU), page 2 MID 144 Vehicle Electronic Control Unit, Diagnostic Trouble Codes (DTCs), page 3 Information is subject to change without notice. Illustrations are used for reference only and may differ slightly from the actual vehicle being serviced. However, key components addressed in service information are represented as acculy as possible. PV776-88974911 USA42335
Service Bulletin 6.2010 364 00 2(12) MID 144 Vehicle Electronic Control Unit (VECU) The manufacturer scan tool is the preferred tool for performing diagnostic work. Contact your local dealer for more information or visit www.premiumtechtool.com. System Overview The VECU is a microprocessor based controller, programmed to perform several functions, these include: Driver controls Vehicle and engine speed controls Starter control Cab power Broadcasting data on the serial data lines Trip data logging Diagnostic trouble code (DTC) logging and password processing The VECU performs these functions by monitoring the signals from sensors and switches, and data over the data link from the other modules. The VECU directly monitors the throttle position (TP) sensor and vehicle speed sensor (VSS). The SAE J1587 data link is primarily used for programming, diagnostics and data reporting. In addition to switch and sensor data, the broadcast between modules also includes various calculations and conclusions each module has developed, based on the input information it has. These calculations and conclusions are part of the modules on board diagnostic (OBD) capability. 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, a DTC will be logged in one or both of the modules memory. The vehicle operator will be advised that a fault has occurred by the illumination of a instrument panel telltale lamp and a message in the driver information display, if equipped. For diagnostic software, contact your local dealer or visit www.premiumtechtool.com. The VECU also monitors the position or state of multiple switches, to perform its control and diagnostic functions. The following is a list of some of the inputs that are monitored: A/C Pressure Switch Air Suspension Height Control Switch Differential Lock Switch Engine Brake Switches Ignition Key Switch Service and Park Brake Switches Speed Control Switches (Set/Decel, Resume/Accel) The VECU communicates with other modules and shares its inputs through the SAE J1939 and SAE J1587 data links.
Service Bulletin 6.2010 364 00 3(12) MID 144 Vehicle Electronic Control Unit, 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. The electronic control units (ECUs) on the SAE J1587 data link communicate according to the SAE J1587 standard. The standard has been extended with supplements (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 ECU. SID Subsystem Identification Description: Identification of a component. PID PPID Parameter Identification Description: Identification of a parameter (value). Proprietary Parameter Identification Description: Unique identification of a parameter (value). PSID FMI Proprietary Subsystem Identification Description: Unique identification of a component. Failure Mode Identifier: Identification of fault types. 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 circuit to higher 4 Abnormally low 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 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
Service Bulletin 6.2010 364 00 4(12) MID 144 Vehicle ECU, Fault Codes PID MID 144 PID 84 Vehicle Speed, page 5 MID 144 PID 86 Cruise Control, Set Speed, page 5 MID 144 PID 91 Accelerator Pedal Position (APP) (Percentage), page 5 MID 144 PID 152 Vehicle Electronic Control Unit (VECU), Number of Resets, page 6 MID 144 PID 191 Output Shaft Speed (OSS), page 6 PPID MID 144 PPID 69 Buffered Idle Validation (IV) Switch, page 6 MID 144 PPID 70 Pedal Switches, Supply, page 7 MID 144 PPID 71 Cruise Control and Engine Brake, Switch Supply, page 7 MID 144 PPID 72 Accelerator Pedal Position (APP) and Engine Brake, Sensors Supply, page 7 MID 144 PPID 74 Vehicle Electronic Control Unit (VECU), Power Supply, page 8 MID 144 PPID 265 Vehicle Speed Sensor (VSS) Supply, page 8 SID MID 144 SID 230 Idle Validation (IV) Switch 1, page 8 MID 144 SID 231 SAE J1939 Data Link, page 9 MID 144 SID 240 Program Memory, page 9 MID 144 SID 243 Cruise Control Set Switch, page 9 MID 144 SID 246 Brake Pedal Position (BPP) Switch, page 9 MID 144 SID 250 SAE J1587 Data Link, page 9 MID 144 SID 253 Calibration Memory EEPROM, page 10 PSID MID 144 PSID 1 Retarder Control Set Switch, page 10 MID 144 PSID 14 DataMax General Error, page 10 MID 144 PSID 200 Communication Interference, Data Link, Engine Control Module (ECM), page 10 MID 144 PSID 202 Communication Interference, Data Link, Instrumentation, page 10 MID 144 PSID 204 Communication Interference, Data Link, Brake Control Module, page 11 MID 144 PSID 205 Communication Interference, Data Link, Transmission Control Module (TCM), page 11 MID 144 PSID 206 Communication Interference, Data Link, Retarder Control Module, page 11 MID 144 PSID 207 Communication Interference, Data Link, Gear Selector Control Module, page 11 MID 144 PSID 211 SAE J1939 Data Link Interruption, Collision Avoidance Control Module, page 11 MID 144 PSID 230 Software Fault, page 12
Service Bulletin 6.2010 364 00 5(12) MID 144 PID 84 Vehicle Speed FMI 2 FMI 14 Intermittent or incorrect data Special instructions Speed signal from speedometer and anti lock brake system (ABS) differs too much Intermittent faulty data Speed signal from vehicle speed sensor (VSS) was updated incorrectly Gauge drops/inoperable N/A MID 144 PID 86 Cruise Control, Set Speed FMI 14 Special Instructions Timeout on adaptive cruise control (ACC) 1 message with ACC installed N/A Vehicle speed sensor (VSS) Harness VSS sensor SAE J1587 data link Wiring harness Faulty or no information from ACC (VORAD) Wiring harness MID 144 PID 91 Accelerator Pedal Position (APP) (Percentage) FMI 3 FMI 5 Abnormally high circuit to higher current or open circuit Voltage above 4.3V Voltage below 0.4V Input too low compared to IV switch 1 and 2 APP harness shorted high Faulty APP sensor APP harness shorted low Faulty APP sensor Faulty APP sensor
Service Bulletin 6.2010 364 00 6(12) FMI 6 Abnormally high current or short circuit to ground Input too low compared to IV switch 1 and 2 Faulty APP sensor FMI 14 Special Instructions Supply Error from PPID 72 APP harness MID 144 PID 152 Vehicle Electronic Control Unit (VECU), Number of Resets FMI 12 Faulty module or component Internal software fault causing a reset System restarted VECU MID 144 PID 191 Output Shaft Speed (OSS) FMI 5 FMI 6 current or open circuit Abnormally high current or short circuit to ground Lower current then expected Higher current then expected N/A N/A Faulty vehicle speed sensor (VSS) Wiring harness Faulty vehicle speed sensor (VSS) Wiring harness MID 144 PPID 69 Buffered Idle Validation (IV) Switch FMI 3 Abnormally high circuit to higher Buffered IV switch 1 too high compared to IV switch 2 signal Buffered IV switch 1 too low compared to IV switch 2 signal Signal shorted high Signal shorted low
Service Bulletin 6.2010 364 00 7(12) MID 144 PPID 70 Pedal Switches, Supply Voltage below 3V Idle Validation (IV) switch shorted low Faulty connector Supply shorted low MID 144 PPID 71 Cruise Control and Engine Brake, Switch Supply Voltage below 3V fuel increase Cruise control switch shorted low Faulty connector Supply shorted low MID 144 PPID 72 Accelerator Pedal Position (APP) and Engine Brake, Sensors Supply FMI 3 Abnormally high circuit to higher Voltage above 5.7V Voltage below 4.7V Requested fuel not supplied to engine Engine brake retarder is disabled Requested fuel not supplied to engine Engine brake retarder is disabled APP sensor harness shorted high APP sensor Accelerator pedal position sensor harness shorted low Accelerator pedal position sensor
Service Bulletin 6.2010 364 00 8(12) MID 144 PPID 74 Vehicle Electronic Control Unit (VECU), Power Supply Voltage below 4.7V Display show minimum wet tank pressure VECU power supply relay Signal shorted low MID 144 PPID 265 Vehicle Speed Sensor (VSS) Supply FMI 3 Abnormally high circuit to higher Voltage above 9V Voltage below 6.5V VSS harness shorted high Faulty VSS VSS harness shorted low Faulty VSS MID 144 SID 230 Idle Validation (IV) Switch 1 FMI 7 Incorrect response from a mechanical system Faulty readout from IV switch 1 IV switch IV switch connector IV switch harness
Service Bulletin 6.2010 364 00 9(12) MID 144 SID 231 SAE J1939 Data Link FMI 2 Intermittent or incorrect data Vehicle electronic control unit (VECU) doesn t get acknowledgement on sent messages MID 144 SID 240 Program Memory FMI 2 Intermittent or incorrect data Check sum calculated at startup differs from the stored one Vehicle electronic control unit (VECU) keeps resetting Vehicle not drivable MID 144 SID 243 Cruise Control Set Switch FMI 7 Incorrect response from a mechanical system Signals SET+ and SET- at the same time Cruise control deactivated CAN communication SAE J1939 data link down/shorted Software error Faulty flash hardware VECU Connector MID 144 SID 246 Brake Pedal Position (BPP) Switch Voltage lower than expected or shorted to N/A Faulty BPP switch MID 144 SID 250 SAE J1587 Data Link FMI 2 Intermittent or incorrect data Faulty messages on the link Some functional disturbances may occur SAE J1587 data link down/shorted
Service Bulletin 6.2010 364 00 10(12) MID 144 SID 253 Calibration Memory EEPROM FMI 2 FMI 14 Intermittent or incorrect data Special instructions Datasets have incorrect checksum Incorrect data found in datasets Error when programming Some functions may be deactivated Some functions may be deactivated MID 144 PSID 1 Retarder Control Set Switch FMI 7 Incorrect response from a mechanical system Signals SET+ and SET- at the same time MID 144 PSID 14 DataMax General Error Retarder Control deactivated Clock or other data missing N/A Faulty EEPROM Vehicle electronic control unit (VECU) Faulty EEPROM VECU Connector Clock or other data missing MID 144 PSID 200 Communication Interference, Data Link, Engine Control Module (ECM) Expected ECM SAE J1939 data link down/shorted MID 144 PSID 202 Communication Interference, Data Link, Instrumentation Expected instrument cluster SAE J1939 datalink down/shorted
Service Bulletin 6.2010 364 00 11(12) MID 144 PSID 204 Communication Interference, Data Link, Brake Control Module Expected anti lock brake system (ABS) SAE J1939 datalink down/shorted MID 144 PSID 205 Communication Interference, Data Link, Transmission Control Module (TCM) Expected TCM SAE J1939 datalink down/shorted MID 144 PSID 206 Communication Interference, Data Link, Retarder Control Module Expected retarder SAE J1939 datalink down/shorted MID 144 PSID 207 Communication Interference, Data Link, Gear Selector Control Module Expected gear selector control module SAE J1939 datalink down/shorted MID 144 PSID 211 SAE J1939 Data Link Interruption, Collision Avoidance Control Module Expected adaptive cruise control (ACC) SAE J1939 datalink down/shorted
Service Bulletin 6.2010 364 00 12(12) MID 144 PSID 230 Software Fault Uncontrolled software reset Wiring harness loss or interruption of supply to vehicle electronic control unit (VECU) Faulty software VECU