P2629 — Oxygen sensor circuit issue on bank 2, sensor 1
The engine control module detected a problem with the oxygen sensor's electrical circuit on the second bank, first sensor. This sensor helps the engine adjust fuel mixture for efficient combustion.
Common causes
The cause is almost always one of a few things. Here they are — P2629 rarely comes from anything outside this list:
- Faulty oxygen sensor on bank 2 sensor 1
- Damaged or corroded wiring/connectors in sensor circuit
- Exhaust leaks near the sensor
- Engine control module (ECM) malfunction
- Contaminated or aged sensor
Where to start
In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:
- Inspect and repair wiring/connectors for damage or corrosion
- Check for exhaust leaks near sensor and fix if found
- Clear code and test sensor operation
- Replace oxygen sensor if faulty
- Test ECM if problem persists after sensor replacement
That is what holds for P2629 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.
Why TorqFix for your car?
Above is what the code means and why it appears. TorqFix goes further — it gives you specific procedures, torque values, wiring diagrams and pinouts for your exact engine, not generic steps for every car. Real workshop data (127,000+ diagrams, 10,000+ procedures), interpreted by AI in your language.
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Code breakdown
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
The same code can mean different things on different makes. Match the meaning to your make before acting on it.
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