P2196O2 Sensor Signal Biased/Stuck Rich (Bank 1, Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2196 means the front oxygen or air-fuel sensor on bank 1 reports a rich mixture that the ECM does not accept. On GM's Bosch-based 2005 V6 this is a cross-check with the rear sensor: the rear sensor reads lean (below 0.15 V) while the front A/F sensor reads richer than lambda 0.92 and the short-term trim has pulled to its minimum of 0.75, for about 100 s or 50 s in total. Ford sets it for a narrow-band sensor that hardly switches and stays rich, a wide-band sensor that sits 30 s at the short-term trim limit, or, from 2019, a filtered lambda below 1 that changes by less than 0.0001 for 30 s; Ford blocks the stuck-rich test while fuel is boiling off the oil after a cold start. On the Opel/GM 2.0 turbo in the Saab 9-5 (2010) the code sets within 4 s continuously or 50 s in total. Because the ECM leans the engine to follow the false signal, a rear sensor reading lean and a lean real mixture often accompany it.
- What you may notice
- Malfunction indicator lamp on
- Possible hesitation or lean running
- Likely causes
- LikelyFront oxygen or A/F sensor contaminated or aged
- RareSensor signal shorted or reference circuit fault
- 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 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.