Emissions

P0150 — O2 Sensor Circuit Malfunction (Bank 2, Sensor 1)

Severity: medium Drive with care, to a shop

What P0150 means

The PCM monitors the upstream oxygen sensor (before the catalytic converter) on bank 2, sensor 1. This sensor reports the air-fuel mixture, and the PCM uses it to adjust fueling. The code sets when the signal or circuit is out of range, such as an open, a short, or a missing or sluggish response.

Symptoms

  • Check Engine Light on
  • Worse fuel economy
  • Rough idle or hesitation
  • Poor acceleration
  • Higher emissions or a failed emissions test
  • Possible misfire or stalling
  • Often accompanied by P0420/P0430

Possible causes

  1. Failed bank 2 sensor 1 oxygen sensor
  2. Open, shorted or corroded wiring or connector
  3. Oxygen sensor heater circuit fault
  4. Exhaust leak near the sensor
  5. Sensor tip fouled by oil or coolant
  6. PCM failure (rare)

How to diagnose

  1. Read all codes and freeze frame data, and look for related mixture or misfire codes
  2. Confirm which side is bank 2 on this engine and locate sensor 1
  3. Inspect the harness and connector for chafing, heat damage, corrosion or oil
  4. Check for exhaust leaks upstream of and near the sensor
  5. Watch live data: sensor voltage or current, response to rich and lean changes, heater status
  6. Test heater resistance, power and ground at the connector, and wiring continuity to the PCM
  7. Review short- and long-term fuel trims for mixture problems
  8. Clear the code and road test to see if it returns

Common fixes

  • Replace the bank 2 sensor 1 oxygen sensor
  • Repair damaged wiring or replace the connector
  • Fix the exhaust leak
  • Correct the source of oil or coolant contamination
  • Repair or replace the PCM only after everything else is ruled out

P0150 on different brands

Ford · manuals
Ford's 2024-2025 gasoline-engine monitor can report this as P0150:11, a low-voltage (short to ground) condition in the circuit; it identifies the detected condition, not a confirmed failed part.

Questions and answers

What does P0150 mean?

It means the PCM sees a faulty or missing signal from the upstream oxygen sensor on bank 2, sensor 1.

Can I drive with P0150?

Briefly, yes, but fuel economy will suffer and the mixture is not controlled well. Get it diagnosed soon to avoid harming the catalytic converter.

Do I always need a new oxygen sensor?

No. Wiring, connector problems and exhaust leaks commonly cause this code, so check them before replacing the sensor.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.