I just replaced my ECM to fix a P0032 CEL and wanted to share my experience. Thought this might help someone else with the same code or replacing an ECM for a different reason. Having a custom tune and Cobb AP adds more complexity.
CEL Code:
P0032 front O2 sensor heater control circuit high input
Cause:
Front O2 sensor wires shorted and damaged ECU AF circuit. I recently installed a Killerb ELH and needed to lengthen the O2 harness. I used two O2 sensors to make a new longer harness by cutting a old one close to the sensor and a good one close to the connector. For my splice, I used high quality crimped connectors, shrink tubing and covered with high temp sheathing. I also made sure the splice was secured several inches from the header. Eventually the shrink tubing completely melted and the wires made contact, causing the O2 heating current to short the ECM signal circuit.
O2 sensor fix:
Purchased a new sensor ($133) and an O2 extension wire harness ($19).
ECM Replacement:
1. I purchased a new ECM ($496)
2. Scheduled a 1 hour service with a Subaru dealer ($125)
3. Pulled back pass carpet and removed ECM shield (not necessary but made the swap faster)
4. Drove to dealer with tools, ECM, Cobb AP, all keys and key security code (on metal keychain tag)
5. Arrived 30 min early to explain the situation (they reluctantly agreed to help)
6. Service tech pulled car into service bay with me in the car
7. (Me) Unmarried Cobb AP and loaded factory tune
8. (Me) Disconnected battery
9. (Me) Swapped ECM
10. (Me) Connected battery
11. Service tech performed registration of immobilizer and programmed keys (key security code was helpful)
12. (Me) Remarried Cobb AP and custom tune
13. (Me) Checked all keys and confirmed no codes
(Note: tech said he likely wouldn’t been able to register a used / previously registered ECM)
Alternative Options:
1. ECM repair (estimated $250 and 7 day turnaround, but they didn’t sound professional on the phone and couldn’t find anyone reporting success)
2. Swap immobilizer chips (I have good soldering experience, but still seemed risky)
3. Read and flash immobilizer data (Would need to brush up on scripting skills and saw mixed success)
Overall, this wasn’t as bad as expected, but it sucks being at the mercy of the dealer. It was an expensive ($750) and time consuming lesson I hope to never make again. The service tech was pretty cool, but the service manager told him “never agree to do again”. He said they’ve been burned too many times with Cobb AP situations.