U1064 Loss of PZM Serial Data Communication - HVAC

CIRCUIT DESCRIPTION

DTC U1064 will set if the ignition is ON and the heater and A/C programmer or the CCP has lost data communication with the Body Control Module (PZM).

Diagnosis of this DTC is dependent upon other system symptoms (DTCs) being present with U1064.

TEST CONDITION(S)

1. Ignition is ON.

FAILURE CONDITION(S)

1. Open circuit.

ACTION TAKEN

1. Set DTC U1064.

TROUBLESHOOTING HINTS

1. Using a scan tool, attempt to establish communications with PZM.
2. Check CKT 1807 for an open or short to power or ground.
3. Check that PZM is connected to power and ground.
4. DTC U1153, loss of CCP serial data communications, may be present with this DTC. If so, this would indicate that both the PZM and CCP were functional when the DTC set, but they could not communicate with one another. Refer to the diagnostic charts for PZM DTCs in Body Control Module (PZM) Diagnosis. Body Control Module
5. If there are multiple Class 2 DTCs current check, for a short to ground or voltage in CKT 1807.
6. Make sure PZM is operating properly. If the PZM is operating normally replace either the heater and A/C programmer or the CCP, depending upon which component set the DTC and is being diagnosed.