P2195 - O2/A-F Sensor Signal Stuck Lean (B1S1)
Upstream O2/A-F sensor signal stuck lean (bank 1).
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Code Overview
Upstream O2/A-F sensor signal stuck lean (bank 1).
Common Causes
- Vacuum/exhaust leak
- Fuel delivery issue
- Sensor fault
- Injector/pressure issue
Symptoms
- Lean surge or hesitation
- Poor cold-start fueling correction
- High positive fuel trims
- Check engine light with fuel-control symptoms
Diagnostic Steps
- Check fuel trims
- Inspect vacuum/exhaust leaks
- Verify sensor response on scan tool
- Check fuel pressure if needed
- Review fuel trims at idle and cruise
- Inspect for intake or exhaust leaks before replacing the sensor
- Verify upstream sensor response on the scan tool
- Check fuel pressure and injector performance if the lean condition is real
Likely Repairs & Cost Guides
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Estimator-ready next step after the fault path is confirmed.
Estimator-ready next step after the fault path is confirmed.
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Next Steps
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