P2195: O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 1)

What does P2195 mean?

The upstream bank 1 oxygen or air/fuel sensor reports a lean-biased signal that does not respond as expected. The engine may truly be lean, or the sensor, heater, and circuit may be giving false feedback.

Generic OBD-II definition: O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 1). Confirm applicability in your vehicle service information.

Common causes

• Intake/PCV vacuum leak
• Low fuel pressure or injector problem
• Faulty upstream O2/A/F sensor or heater
• Damaged sensor wiring

Symptoms

• Check engine light
• Possible rough idle
• Hesitation or poor economy

Diagnostic focus

Wideband air/fuel sensors need their own test values. Do not apply a conventional narrowband 0-to-1-volt switching rule to every sensor identified by this code.

Can I keep driving with P2195?

Severity: Medium Drive gently and get it diagnosed soon.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Compare fuel trims and both banks if fitted
• Inspect vacuum leaks and sensor wiring
• Verify fuel pressure and sensor response before replacement

Sources & review

• OBD-Codes.com: P2195
• TroubleCodes.net: P2 code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.