P2273: O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 2
What to do
The car will usually drive normally. If both banks report stuck rear sensors at once, that points at something they share rather than two failed sensors. Do not agree to a converter on this bank until the sensor is resolved.
What this code means
The stuck-rich condition of P2271, on the post-catalyst sensor of the second bank. The oil and coolant consumption caution applies equally, and so does the warning that the catalyst verdict for this bank is not trustworthy until the sensor is.
Where both banks report stuck rear sensors together, the shared-cause argument applies as it does throughout this range: two rear sensors failing at once is less likely than the supply, ground or module input they have in common.
Likely causes
Start here
- Faulty oxygen sensor · moderate
- Contaminated oxygen sensor element · moderate
Less common
- Excessive oil or coolant consumption · specialist
- Failed sensor reference voltage supply · moderate
- Damaged wiring harness · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
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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