P22B6O2 Sensor Pumping Current Trim 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
- By its name P22B6 is the low fault on the trim line of the bank 1 downstream wide-band probe, i.e. the lead to the calibration resistor in a Bosch-style sensor connector. GM's diesel tables use the slot differently: they set it when the oxygen value reported by the second NOx sensor falls below its physical minimum, less than -4 % in 200 of 250 samples in the 2016 table, with the engine in combustion mode and no NOx sensor fault pending. It is a Type B code with two trips. GM also lists P22B6 in PIP5468 for 2017-2018 Silverado/Sierra HD with the 6.6 L5P, where leaking charge-air ducting can set it, and in 21-NA-149 for the 3.0 LM2. P22B5 is the open, P22B7 the high counterpart, P22C3 bank 2. The lamp comes on.
- What you may notice
- Check engine light
- Negative oxygen percentage shown for the downstream sensor in live data
- Possible additional boost or air-flow codes when charge air leaks
- Likely causes
- PossibleFaulty downstream NOx/oxygen sensor delivering an impossible oxygen value
- PossibleLeaking charge-air cooler ducting (GM 6.6 L5P)
- PossibleTrim or signal wire shorted to ground in the harness
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.