Circuit/System Testing

P0AF8

1. Verify the DTC is set as current.
2. Ensure the hood is fully closed. Ignition ON, observe and record the scan tool Hybrid Battery System Voltage parameter in the SGCM data list.
3. Open the hood. Gain access to the 36 volt output cable connection at the SGCM refer to Generator Control Module Cover Replacement 
4. Measure the voltage at the 36 volt output cable connection at the SGCM to ground, the voltage should not differ by more than 3 volts than the scan tool parameter recorded in step 2.
   • If greater than the specified value replace the SGCM.
5. Ignition ON, observe and record the scan tool Hybrid Battery System Voltage parameter in the BECM data list.
6. Ignition OFF, remove the Hybrid Battery Pack service cover refer to Hybrid Battery Service Disconnect/Connect Inspect the 36 volt and ground cable connections of the Hybrid Battery Pack.
7. Depress and hold the service disconnect for 20 seconds and measure the voltage at the Hybrid Battery Pack the 36 volt terminal to ground. The voltage should not differ by more than 3 volts from the voltage measured in step 4.
   • If greater than the specified value, test the 36 volt cable for short to ground or an open/high resistance.
8. Note some vehicles have a plastic cover over this area to be measured that must be removed. Measure the voltage at the Hybrid Battery Pack the 36 volt terminal pack side of contactor to ground. The voltage should not differ by more than 3 volts from the scan tool parameter display in step 5.
   • If greater than specified value inspect the Hybrid Battery Pack ground cable for an open/high resistance or the Hybrid Battery Pack fuse for an open.
9. If the ground circuit tests normal, the fuse was not open and voltage differs by more than 3 volts. Replace the BECM.