O2 Sensor Signal Stuck Rich (Bank 2, Sensor 3)
What does P2275 mean?
The P2275 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Signal Stuck Rich (Bank 2, Sensor 3). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Failed emissions test
- Rich exhaust smell
- No major performance changes
- Possible secondary catalytic converter code
Probable Causes (Ranked by Likelihood)
- Faulty Bank 2 Sensor 3 O2 sensor Very High
- Engine running rich due to upstream fuel delivery issue High
- Oil or coolant contamination of the sensor Moderate
- Wiring short to voltage on the sensor signal wire Moderate
- Secondary catalytic converter failure allowing rich exhaust through Low
Step-by-Step Diagnostic Procedure
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Monitor Bank 2 Sensor 3 voltage -- check if stuck above 0.6V
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Review Bank 2 fuel trim data for a genuine rich running condition
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Inspect the sensor for oil or coolant contamination
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Check the sensor wiring for shorts to power
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Replace the O2 sensor if wiring and fuel trims are normal
Frequently Asked Questions
What does stuck rich on Sensor 3 indicate?
A stuck rich reading on Sensor 3 indicates the sensor is consistently reading high voltage (rich) after the secondary catalytic converter. This is typically a sensor failure or a rich exhaust condition passing through both converters.
Can a rich condition damage the downstream catalytic converter?
Yes, excess unburned fuel reaching the downstream converter can cause it to overheat and fail prematurely.
Should I diagnose Sensor 3 codes differently than Sensor 2?
The diagnostic approach is similar, but Sensor 3 faults are less likely to affect drivability. Focus on the sensor itself and check for exhaust leaks at the Sensor 3 location.