P22B9O2 Sensor Positive Current Control Circuit Low (Bank 2 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
- P22B9 means the positive current control (pump-current) line of the bank 2 downstream wide-band probe reads below its allowed band, most often because the lead has worn through and touches ground. No maker documents this code publicly, so the logic can only be inferred from the bank 1 and upstream relatives: GM lists P22AC for the 3.0 Duramax LM2 without a threshold, Saab treats the upstream P2238 as a Type B fault, and Ford books upstream shorts as P0131. CARB requires out-of-range detection on air-fuel sensors behind the aftertreatment. The fault needs a V or boxer engine with a wide-band probe after each catalyst. P22B8 is the open, P22BA the high variant, P22AC the bank 1 code. A lit warning lamp is usually the only symptom.
- What you may notice
- Check engine light
- Bank 2 downstream oxygen value at an extreme
- Likely causes
- LikelyPump-current wire chafed through and shorted to ground
- PossibleInternal short in the bank 2 downstream sensor
- RareWater in the 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: €50 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.