Circuit Description
Normally, switches, accelerators, and other components are connected to the engine electronic control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) VECU or transmission electronic control unit in the cab. Then component values and states from components (such as sensors, accelerators, and switches) can be transmitted from the OEM VECU to the Cummins? engine ECM over the SAE J1939 data link.Messages sent from the OEM VECU or transmission electronic control unit are received by the Cummins? engine ECM and used for controlling the engine. The Cummins? ECM and OEM VECU must be configured properly so that proper operation of the multiplexed components will occur.
Component Location
The J1939 data link wiring and VECU location varies by OEM.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the key switch is in the on position or when the engine is running.
Conditions for Setting the Fault Codes
The OEM VECU determines that there is a malfunction of the multiplexed accelerator pedal or lever sensor system.
Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp and/or Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.
The fault code status displayed by the INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the red STOP ENGINE lamp after the diagnostic runs and passes.
For On Board Diagnostic (OBD) engines, the ECM will turn off the MIL after 3 consecutive trips where the diagnostic runs and passes.
The ?Reset All Faults? command in the INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications
Shop Talk
The J1939 multiplexing controller has indicated a malfunction of the multiplexed accelerator pedal.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.
Possible Cause:
1) ECM calibration
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