Fault-Code Library · Fuel mixture / emissions
P2195: Oxygen sensor signal stuck lean, bank 1 sensor 1
The upstream oxygen sensor on bank 1 remains at a lean indication despite ECU correction.
Common symptoms
- •Engine warning light
- •Rough idle
- •Hesitation
- •Higher fuel use
Likely causes
- •Vacuum leak
- •Exhaust leak before the sensor
- •Low fuel pressure
- •Biased oxygen sensor
First checks
- •Review fuel trims
- •Smoke-test the intake
- •Inspect exhaust leaks and sensor response before replacement
Important
The code can describe a genuinely lean engine rather than a failed sensor; diagnose mixture and sensor together.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
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