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 P0A84: Hybrid Battery Pack Cooling Fan Control Circuit Low VoltageDTC P0A85: Hybrid Battery Pack Cooling Fan Control Circuit High Voltage
Circuit/System Description
The battery energy control module (BECM) monitors the cooling fan to detect if the fan speed is slower or faster than is being commaned. If a failure is detected, the appropriate DTC will set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P0A84
| • | Fan control feedback is less than 5 percent. |
| • | Fan state is ON. |
P0A85
| • | Fan control feedback is greater than 95 percent. |
| • | Fan state is ON. |
| • | Fan command is less than 80 percent. |
Action Taken When the DTC Sets
The hybrid system is not affected.
Conditions for Clearing the DTC
The fan speed control feedback is normal.
Reference Information
Schematic Reference
Connector End View Reference
Hybrid Cooling Connector End Views
Electrical Information Reference
Scan Tool Reference
Special Tools
J 35616 GM Approved Terminal Test Kit
Circuit/System Verification
Caution: 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.
- Verify the DTC is set current, clear the DTC.
- 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. |
Circuit/System Testing
Important: In order to avoid damaging BECM C1 and C2 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 |
- Ignition OFF, disconnect the cooling fan harness connector. Refer to Hybrid Battery Service Disconnect/Connect
- Disconnect BECM harness connector C2.
- Test the Fan Tach Feedback circuit C2 connector terminal 11 to cooling fan harness connector terminal 4 for a short to voltage, short to ground or an open/resistance.
- If the circuit test normal replace the hybrid battery pack cooling fan.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Generator Battery Vent Fan Replacement
Control Module References for BECM replacement, setup, and programming
