P0150 serious

O2 Sensor Circuit Malfunction (Bank 2, Sensor 1)

What does P0150 mean?

The P0150 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Circuit Malfunction (Bank 2, Sensor 1). This is a serious severity code.

Common Symptoms

  • Check Engine Light on
  • Poor fuel economy
  • Rough running
  • Rich or lean condition
  • Failed emissions

Probable Causes (Ranked by Likelihood)

  • Failed Bank 2 upstream O2 sensor Very High
  • Wiring fault to Bank 2 sensor High
  • Exhaust leak near Bank 2 sensor Moderate
  • Sensor heater failure Moderate

Step-by-Step Diagnostic Procedure

  1. Identify Bank 2 on your engine (the side without cylinder 1). Locate the upstream O2 sensor on that side.

  2. Monitor Bank 2 Sensor 1 voltage: should switch 0.1-0.9V at idle.

  3. Compare Bank 1 and Bank 2 fuel trims: if Bank 2 is significantly different, focus diagnosis there.

  4. Test heater, wiring, and sensor as with P0130.

Frequently Asked Questions

How do I find Bank 2 Sensor 1 on a V8?

On most American V8s (Ford, GM, Dodge), Bank 2 is the passenger side. Sensor 1 is the sensor before the catalytic converter on that side -- usually located on the exhaust manifold or just downstream of it.

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