P2237O2 Sensor Positive Current Control Circuit/Open (Bank 1 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2237 points to an open pump-current line (IP or APE) on the front wide-band sensor of bank 1. With that wire broken the output freezes near its stoichiometric value of roughly 1.5 V and lambda stops moving. Ford sets it on Bosch sensors when 20 s of fuel-control steps and reference-current pulses shift lambda by 0.05 or less; NTK interface chips report the open line directly. VW's 2014 books look for 1.49-1.51 V while the lambda controller deviates by more than 0.10 or fuel has been cut for over 3 s, and Saab's 9-5 2.0 turbo (2010) logs it as Type B. Software updates cure false or damaging cases on VW Jetta/Beetle 2.0 (2013-14, plus a new sensor) and Hyundai Kona 1.6 T-GDI (2024-25). P2238/P2239 are low/high, P2240 is bank 2.
- What you may notice
- Check engine light
- Lambda reading stuck at 1.0 in live data
- Higher fuel consumption in open-loop fuelling
- Likely causes
- LikelyBroken pump-current wire or pushed-back pin between sensor and ECM
- PossiblePump cell of the wide-band sensor damaged, for example by catalyst-heating strategy or thermal shock
- RareEngine software that sets the code falsely (update available for some models)
- 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 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.