O2 Sensor Signal Stuck Rich (Bank 2, Sensor 2)
The P2272 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Signal Stuck Rich (Bank 2, Sensor 2). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $75 - $300 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Poor fuel economy
- Rich exhaust smell
- Possible catalytic converter efficiency code
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Faulty downstream O2 sensor on Bank 2 Very High
- Exhaust leak near the Bank 2 Sensor 2 location High
- Engine actually running rich on Bank 2 Moderate
- Contaminated sensor from oil or coolant in exhaust Moderate
- Wiring short causing artificially high voltage reading Low
Step-by-Step Diagnostic Procedure
-
Monitor Bank 2 Sensor 2 voltage -- check if stuck above 0.6V
-
Check Bank 2 fuel trim data to determine if the engine is actually rich
-
Inspect for exhaust leaks between the catalytic converter and the sensor
-
Check for signs of oil or coolant in the exhaust stream
-
Swap Bank 1 and Bank 2 downstream sensors to see if fault follows the sensor
Frequently Asked Questions
What does stuck rich mean for the downstream sensor?
It means the Bank 2 post-catalytic converter O2 sensor is consistently reading rich (high voltage), indicating either a faulty sensor or a genuine rich exhaust condition after the converter.
Can a bad catalytic converter cause P2272?
Yes, a failed catalytic converter that is not converting exhaust gases properly can cause the downstream sensor to read rich.
Should I replace the sensor or fix the rich condition first?
Check fuel trims first. If the engine is running rich, fix the underlying cause. If fuel trims are normal, the downstream sensor is likely faulty and should be replaced.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P2272 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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