U1096 Loss of IPC Serial Data Communication - HVAC

CIRCUIT DESCRIPTION

DTC U1096 will set if the ignition is ON and the heater and A/C programmer or CCP has lost data communication with the IPC. This DTC should be seen only as a history DTC. If communications are currently inoperative the heater and A/C programmer or CCP will not be able to communicate with the IPC to display the DTC.

Diagnosis of this DTC is dependent upon other system symptoms (DTCs) being present with U1096.

TEST CONDITION(S)

^ Ignition is ON.

FAILURE CONDITION(S)

^ Open circuit.

ACTION TAKEN

1. Set DTC U1096.

TROUBLESHOOTING HINTS

1. Using a scan tool attempt to establish communications with IPC.
2. Check CKT 1807 for an open or short to power or ground.
3. Check that the IPC is connected to power and ground.
4. IPC DTC U1152 or IPC DTC U1153 may be present with this DTC. If so, this indicates that both the Body Control Module (PZM) and the heater and A/C programmer or CCP were functional when the DTC set, but they could not communicate with one another. Refer to Body Control Module (PZM) Diagnosis for the diagnostic charts for PZM DTCs. Body Control Module
5. If there are multiple Class 2 DTCs current, check for a short to ground or voltage in CKT 1807. Refer to Computer System Diagnosis. Testing and Inspection