O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 3
The P2277 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 3. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $150 - $900 (cleaning or a stuck valve at the low end; component replacement at the high end)
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Common Symptoms
- Check Engine Light on
- The affected system is stuck in one state and no longer responds to commands
- Drivability effect depends on which state it is stuck in
- Often preceded by intermittent operation
Probable Causes (Ranked by Likelihood)
- O2 Sensor Signal Biased/Stuck Rich mechanically stuck - carbon, debris, or wear High
- Actuator or motor failed in position High
- Linkage or return spring damage Moderate
- Control circuit fault holding it in one state Moderate
Frequently Asked Questions
What does P2277 mean?
P2277 is a generic OBD-II code defined by SAE J2012 as "O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 3". It means the control module detected a fault in this circuit
Can I keep driving with P2277?
Short trips only. This fault can worsen or put the system into a protective mode without much warning, so have it diagnosed promptly.
Does P2277 mean the same thing on every car?
Yes. P2277 is in the generic (SAE J2012) range, so the definition is standardized across manufacturers. The specific component location and repair procedure still vary by vehicle - check your service information.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Command the O2 Sensor Signal Biased/Stuck Rich through its range with a scan tool and watch the position feedback.
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Inspect for carbon buildup or debris - on intake and EGR components this is the usual cause and cleaning may fix it.
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Check the actuator's linkage and return spring for damage.
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Verify the control circuit before condemning the component.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- All OBD-II vehicles - this is a generic (SAE J2012) code with the same meaning across makes
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