P22ACO2 Sensor Positive Current Control Circuit Low (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
- P22AC means the pump-current (positive current) line of the bank 1 downstream wide-band probe reads below its allowed window, usually because the wire touches ground or its insulation has worn through. GM includes the code in bulletin 21-NA-149 for 2019-2022 light-duty trucks and SUVs with the 3.0 Duramax LM2, where chafed engine wiring triggers a long list of faults; no public GM table gives a threshold. Not every maker uses this slot: Ford books a shorted lead on its upstream wide-band probes as P0131. Saab rates the upstream analog P2238 as a Type B fault. P22AB is the open-circuit case, P22AD the high one, P22B9 the bank 2 copy. Expect a lit warning lamp and stalled emission monitors rather than a change in driving.
- What you may notice
- Check engine light
- Downstream oxygen value pinned at an extreme in live data
- Possible failed emissions inspection because monitors are not ready
- Likely causes
- LikelyPump-current wire chafed against the body or exhaust and shorted to ground
- PossibleInternal short in the downstream wide-band sensor
- RareWater or contamination bridging the connector pins
- 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: €50 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.