P2232O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2232 reports that the heater supply of the oxygen sensor behind the catalyst on bank 1 is bleeding into that sensor's signal line. A switching sensor only produces up to about 1 V, so the ECM watches its signal at the instant the heater is switched off. GM's tables for the 2005 2.8/3.6 V6, the 2008 3.6 LLT and the 2024 set 24OBDG07 flag a jump of more than 2 V within 0.04 s of heater turn-off in more than 4 out of 6 events, with the MIL after two trips. The Saab 9-5 (2010, 2.0 turbo) checks whether signal and heater voltage rise and fall together and treats the fault as Type B. P2231 is the front sensor, P2235 the rear position on bank 2. Mixture control continues, but catalyst monitoring loses its rear signal.
- What you may notice
- Check engine light after two drives
- Catalyst monitor not completed or catalyst code stored alongside
- Likely causes
- LikelyInternal leakage between heater and sensing element of the rear oxygen sensor
- PossibleSignal and heater wires fused or chafed together near the exhaust
- RareWater or corrosion 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: €60 – €280
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.