Cummins ISX12 CM2250 (2010-12) Fault Code: 288 PID: 372 SPN: 974 FMI: 19 SAE J1939 Multiplexing Remote Accelerator Pedal or Lever Position Sensor System- Received Network Data in Error

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 OEM VECU or transmission electronic control unit (ECU) 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? ECM over the SAE J1939 data link.

Messages sent from the OEM VECU or transmission ECU are received by the Cummins? ECM and are 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. Refer to the OEM service manual.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes
The OEM VECU determines that the remote throttle signal wire or enable switch is shorted high or shorted low. This fault status is transmitted to the Cummins? ECM on the J1939 data link, which causes this fault to occur in the Cummins? ECM.

Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE light immediately when the diagnostic runs and fails.
The multiplexed device will not operate.
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 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 Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD engines.

Shop Talk
This fault can occur when the OEM VECU detects an error on the remote throttle and or remote throttle enable switch. The ECM has been set up properly (components enabled and OEM VECU source addressed correctly) to receive multiplexed information for the remote throttle enable switch states and remote accelerator position over the J1939 data link from an OEM VECU, and the OEM VECU is transmitting the message for that component. Most OEM VECUs will not have the circuitry to detect a remote throttle switch error.

The two types of errors that can occur for this fault are:

The OEM VECU determines that the remote throttle signal line is shorted high or shorted low. This fault status is transmitted to the Cummins? ECM on the J1939 data link, which causes this fault to occur in the Cummins? ECM.
When the remote throttle enable switch has a shorted high or shorted low error detected by the OEM VECU, this fault status is transmitted to the ECM on the J1939 data link, which causes this fault to occur in the ECM. Most OEM VECUs will not incorporate fault detection on a switch.
NOTE: It is still possible to get a Fault Code 285 or 286, if there is an incorrect setup in the OEM VECU or Cummins? ECM for other components, or the remote throttle and remote throttle switch, or the data link is damaged. The OEM configurations must multiplex the remote throttle and remote throttle switch inputs together to allow the use of the J1939 multiplexing feature for these components. The INSITE? electronic service tool can be used to monitor multiplexed components.

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) OEM issue
2) ECM failure