I would definitely recommend getting yourself a service manual, find a used one in this forum or subscribe to an online service manual like alldatadiy.com.
Here is some details regarding P0A0C
High Voltage System Interlock Circuit Low Voltage
High Voltage System Interlock Circuit High Voltage
The high voltage interlock circuit is used to determine if access to high voltage components or connectors is being attempted. The opening of these high voltage components causes the high voltage interlock circuit to open. The hybrid/EV powertrain control module 2 sources about 5 V on the high voltage interlock circuit loop. When the hybrid/EV powertrain control module 2 detects a loss of high voltage interlock circuit current, the high voltage contactors are commanded open.
The high voltage interlock circuit monitors for integrity of the following components:
- F103 Power Inverter Module Assembly Case Cover
- S15 Manual Service Disconnect
- A4 Hybrid/EV Battery Pack high voltage harness connector X1
- A4 Hybrid/EV Battery Pack high voltage harness connector X2
Conditions for Setting the DTC
The hybrid/EV powertrain control module 2 detects high voltage interlock circuit 5 V low reference voltage is less than 30 % of the commanded 5 V signal voltage.
Action Taken When the DTC Sets
- DTCs P0A0C and P0A0D are Type A DTCs.
- The hybrid/EV powertrain control module 2 opens the high voltage contactors when vehicle speed is less than 5 km/h (3 mph).
Conditions for Clearing the DTC
DTCs P0A0C and P0A0D are Type A DTCs.
- Test for a fully engaged hybrid battery pack high voltage manual disconnect whenever an open or intermittent high voltage interlock circuit condition is observed. The hybrid battery pack high voltage manual disconnect lever must be pressed down fully in order to completely engage the high voltage interlock circuit terminals.
- The A4 Hybrid/EV Battery Pack high voltage connectors X1 and X2, the S15 Manual Service Disconnect and the F103 Power Inverter Module Assembly Case Cover must all be engaged to complete the interlock circuit loop.
- With all monitored high voltage components engaged and the High Voltage Interlock Circuit is Energized, observe the scan tool hybrid/EV powertrain control module 2 High Voltage Interlock Circuit Status parameter for a PASS status. To help identify intermittent conditions, manipulate the monitored components and inline connectors. An open interlock circuit will display a FAIL status.
An S15 Manual Service Disconnect that is not fully engaged may result in an intermittent DTC PA0C.
Vehicle OFF, disconnect the 12 V battery. Remove the S15 Manual Service Disconnect.
There is quite a bit more detail to the testing bit. Make sure if you verify the integrity of S15 or any of the high voltage interlock connectors, that the car is completely de-energized as they say.
There are more details regarding testing the interlock's components via resistance and visual inspection, but hopefully this gives you an idea on where to start. S15 in particular is under the rear seat cushions.
Again I recommend the service manual if you want to do the troubleshooting yourself. PM me and I can send you a discount code for alldataDIY. You will need to know how to use a multimeter, and it would be instrumental if you had a comprehensive diagnostic tool (or a mechanic friend with one) that you can plug into the OBD port in service mode to test the systems. If you aren't comfortable with doing resistance tests and poking probes into different connectors while the car is off, you might want to research a good electrical car technician (especially one familiar with EVs) in your area with the tools and comfort level to hire.
Lastly, I don't know the nature of the accident and affected areas, but the simplest interlock is under the hood. The plastic engine cover with chevy logo has a bolt that depresses a toggle switch to indicate if the cover has been removed. that could also prevent you from driving or cause intermittent issues. Rich Benoit shows that here https://youtu.be/1HeEK5cLNpw?t=143
. Try inspecting yours.