P2631: O2 Sensor Pumping Current Trim Circuit High Bank 2 Sensor 1
What to do
The car will drive normally with slightly worse economy and incomplete emissions monitors. If exhaust work has been done recently, a disconnected or swapped plug is the first thing to check, as at P2628.
If codes for both banks are stored together, say so explicitly. Two of these sensors do not fail at the same moment in the same way — what they share is a supply, an earth and the module reading them, and that is where a fault affecting both will be. It is worth ruling out before either sensor is bought.
What this code means
The pumping current trim circuit reads above its valid range on the bank 2 upstream sensor — an open circuit, a disconnected connector, or a short to supply. The mechanism is at P2626 and the exhaust-work argument at P2628.
Where both banks show trim faults at once, stop treating them as two sensor problems. Two sensors do not fail simultaneously in the same way. What they share is the module that reads them and the supply and earth that feed both, so a common supply or a module input stage is the explanation that fits — the corpus's most repeated argument, and it is as true here as it is of a reference voltage or an injector group supply. Replacing two sensors to fix one shared fault is an expensive way to find that out.
Likely causes
Start here
- Disconnected sensor connector · easy
- Open circuit in sensor wiring · moderate
- Corroded or loose connector · easy
Less common
- Failed sensor reference voltage supply · moderate
- Faulty oxygen sensor · moderate
- Wiring shorted to voltage · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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