The battery energy control module (BECM) monitors the cooling fan tach circuit to detect if the fan speed is slower or faster than the commanded state. If a failure is detected, the appropriate DTC will set.

The engine is running.

P0A84

P0A85

The hybrid system is not affected.

The fan speed control feedback is normal.

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

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

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.

1. Verify the DTC is set current, clear the DTC.
2. Ignition ON, using the scan tool special function command the hybrid cooling fan ON and OFF several times.

⇒	If the hybrid battery pack cooling fan operates as commanded and the DTC resets, continue with Circuit/System Testing.

⇒	If the hybrid pack cooling fan does not operate as commanded , replace the hybrid battery pack cooling fan.

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:

1. Ignition OFF, disconnect the cooling fan harness connector. Refer to Hybrid Battery Service Disconnect/Connect.
2. Disconnect BECM harness connector X2.
3. Test the fan tach feedback circuit X2 connector terminal 11 to cooling fan harness connector terminal 4 for a short to voltage or a short to ground.
4. If the circuit test normal replace the BECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.