P22B5O2 Sensor Pumping Current Trim Circuit/Open (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P22B5 flags an open trim line on the bank 1 downstream wide-band probe. Bosch LSU probes carry a trimming resistor in the connector module, wired to pin 5 (RT/IA), that sets each sensor's individual characteristic; the controller reads it to scale the measured pump current. Lose that line and the oxygen value can still move, but with the wrong gain. Chrysler's wording speaks of the pump cell current trim of sensor 1/2 and lists the code for 2010-2012 Ram 2500/3500 with the 6.7 Cummins; after the wiring repair its road test compares both sensors during 10-second fuel cut-offs and allows no more than 4 % difference. Saab's upstream analog P2626 is checked in overrun below 750 °C and sets above 4.81 V. P22B6/P22B7 are low/high, P22C2 bank 2.
- What you may notice
- Check engine light
- Downstream oxygen reading disagrees with the upstream sensor during fuel cut-off
- Follow-up aftertreatment or catalyst faults possible
- Likely causes
- LikelyCorroded or loose trim-line terminal in the sensor connector
- PossibleTrim wire broken between sensor connector and ECM or sensor module
- RareOpen trimming resistor in the sensor's connector module
- 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: €0 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.