P2195 — O2 Sensor Signal Stuck Lean (Bank 1 Sensor 1)
Moderate severityWhat it means
P2195 is stored when the engine control unit sees a fault involving the oxygen sensor signal (bank 1 sensor 1). This code means the oxygen sensor signal is stuck to one side instead of switching, so the control unit cannot trim fuel correctly from it. “Lean” means the exhaust shows more air (or less fuel) than ideal, and the control unit has run out of room to add fuel to correct it.
Common symptoms
- Hesitation, misfire or rough idle
- Higher fuel consumption
- Possible misfire or rough running
- Failed emissions test
Likely causes
- An intake or vacuum leak letting in unmetered air
- A weak fuel pump, clogged filter/injectors or a dirty MAF sensor
- An aged or contaminated oxygen sensor
- An underlying mixture fault (leak or fuel problem) skewing the signal
What to check first
- Look for intake/vacuum leaks and check fuel pressure
- Watch fuel trims and the MAF reading in live data
- Watch the sensor switching in live data
- Resolve any mixture/fuel-trim codes before replacing the sensor
Can you keep driving?
Drivable short-term; it wastes fuel and can affect the catalytic converter, so repair soon.
Frequently asked questions
What is the most common cause of P2195?
The most likely cause is: An intake or vacuum leak letting in unmetered air. Several other faults can set P2195 as well, so confirm the real cause with live data and the checks above before replacing any parts.
Can I just clear P2195 and keep driving?
Clearing P2195 with an OBD2 scanner turns the warning light off, but if the underlying fault has not been repaired the code will usually come back within a few drive cycles. Fix the cause first, then clear the code to confirm the repair worked.
How serious is P2195?
P2195 is a moderate-severity code. The car is often still drivable, but have it diagnosed soon — the underlying problem can get worse and it may fail an emissions test.
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