U1040

Wiring Diagram:

Circuit Description:
While the Ignition switch is m RUN" modules communicating on the Class 2 Data Bus send a "State of Health" (SOH) message every 5 seconds to ensure that the system is operating properly.

DTC Will Set When:
The IPC does not receive a "State of Health" (SOH) message from the EBTCM after three consecutive monitoring cycles.

DTC Will Clear When:
The EBTCM transmits a "State of Health" (SOH) message to the IPC.

Troubleshooting Hints
1. If there are multiple Class 2 DTCs (i.e. DTCs U1300, U1301, U1088, U1153), check for a intermittent short to power or ground in CKT 180? (PPL).
2. If DTC is current attempt to establish communications with the EBTCM using a scan tool.
^ If communications can not be established with the EBTCM.
^ If communications can be established with the EBTCM then replace IPC.
3. If the DTC is history, check for intermittent open in CKT 1807 (PPL).