P237BO2 Sensor Exhaust Sample Error (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
- P237B is the bank 2 version of the sample check on the post-catalyst oxygen sensor and therefore only appears on engines with two exhaust banks, mostly V6 and V8 units with a separate downstream sensor on each side. The ECM decides that what the sensor reports cannot be genuine exhaust from that bank, for example because a leak at the second-bank pipe lets air in or the probe is mounted badly. No manufacturer documents P237B publicly; a published example of the method exists only for the front sensor, Volkswagen's P2414 on the 2014 Golf. CARB demands monitoring of rear sensors because the catalyst check relies on them. Related codes are P237A for bank 1 and P2415 for the bank 2 front sensor; code lists use this title again for P23A1. Inspecting the bank 2 exhaust for leaks comes first.
- What you may notice
- Check engine light on
- Bank 2 catalyst monitor incomplete or failing
- Engine runs as usual
- Likely causes
- LikelyAir leak in the bank 2 exhaust between catalyst and rear sensor
- PossibleBank 2 rear sensor damaged, poisoned or not seated correctly
- RareRear sensors of bank 1 and bank 2 swapped at the connectors after a repair
- 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: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.