Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0A81: Hybrid Battery Pack Cooling Fan Control CircuitDTC P0A82: Hybrid Battery Pack Cooling Fan Stuck Off
DTC P0A83: Hybrid Battery Pack Cooling Fan Stuck On
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | P0A82 | P0A82 | -- | -- |
Fan Control | P0A81, P0A83 | P0A81, P0A82 | P0A81 | -- |
Circuit/System Description
The battery energy control module (BECM) monitors to detect if the cooling fan is enabled, in the stuck off position or in the stuck on condition. If a failure is detected, the appropriate DTC will set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P0A81
| • | Enable flag is enabled. |
| • | Fan state is OFF. |
P0A82
| • | Fan speed feedback is less than 5 percent. |
| • | Fan state is ON. |
P0A83
| • | Fan speed feedback is greater than 5 percent. |
| • | Fan state is OFF. |
Action Taken When the DTC Sets
The hybrid system is disabled.
Conditions for Clearing the DTC
P0A81
The fan is not enabled.
P0A82, P0A83
The fan speed feedback is normal.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Starter Generator Control Module Cooling System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 35616 GM Approved Terminal Test Kit
Circuit/System Verification
Ignition ON, using the scan tool special function command the generator battery vent fan ON and OFF several times.
| ⇒ | If the generator battery vent fan does not operate as commanded, continue with Circuit/System Testing. |
Circuit/System Testing
Warning: To help avoid personal injury, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.
Note: In order to avoid damaging BECM X1 and X2 connector terminals, the proper test probes should be used. The proper test probes are as follows:
| • | J-35616-65B for female terminals |
| • | J-35616-64B for male terminals |
P0A81
- Ignition OFF, disconnect the generator battery vent fan harness connector. Refer to Hybrid Battery Service Disconnect/Connect.
- Disconnect the BECM X2 harness connector.
- Test the cooling fan control circuit for an open or high resistance.
- Replace the harness assembly.
| ⇒ | If the circuit tests normal, replace the BECM. |
P0A82
- Ignition ON, with scan tool command the generator battery vent fan ON.
- Ignition OFF, disconnect the generator battery vent fan harness connector. Refer to Hybrid Battery Service Disconnect/Connect.
- Disconnect BECM X2 harness connector.
- Test for less than 1 ohm between the following circuits listed below.
- If all circuits test normal , replace the generator battery vent fan.
| ⇒ | If the fan operates, replace the BECM. |
| • | BECM X2 connector terminal 2 to fan harness connector terminal 1 |
| • | BECM X2 connector terminal 4 to fan harness connector terminal 2 |
| • | BECM X2 connector terminal 3 to fan harness connector terminal 3 |
| • | BECM X2 connector terminal 11 to fan harness connector terminal 4 |
| ⇒ | If greater than the specified range, replace the generator battery vent fan harness assembly. |
P0A83
- Ignition OFF, disconnect the generator battery vent fan harness connector. Refer to Hybrid Battery Service Disconnect/Connect.
- Disconnect BECM X2 harness connector.
- Test the fan control circuit terminal 3 for a short to ground.
| ⇒ | If the circuit tests normal, replace the BECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BECM replacement, setup, and programming |
