P2231O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 1 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2231 means the engine computer sees the heater supply of the upstream oxygen sensor on bank 1 leaking into the sensor's signal path - typically an internal short in the sensor or two neighbouring wires touching in the harness. VW's 2014 specification books for the Passat and Tiguan set it when the front sensor signal changes by more than 190 microamps, i.e. the measured sensor current is distorted. CARB requires circuit faults of every fuel-control oxygen sensor to be detected. P2232/P2233 cover sensors 2 and 3 of bank 1, P2234 the first sensor of bank 2. Because the mixture feedback can no longer be trusted, the engine may run on open-loop fuelling with higher consumption and emissions.
- What you may notice
- Check engine light
- Higher fuel consumption due to open-loop fuelling
- Rough idle or hesitation in some cases
- Likely causes
- LikelyInternal short between heater and sensing element in the oxygen sensor
- PossibleHeater and signal wires melted or chafed together (exhaust heat, routing)
- RareMoisture or contamination bridging pins in the sensor connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.