Emissions

P0050 — Oxygen Sensor Heater Control Circuit (Bank 2 Sensor 1)

Severity: medium Safe to drive

What P0050 means

The PCM powers a heater inside the upstream oxygen sensor on Bank 2 so the sensor reaches operating temperature quickly and can control the fuel mixture soon after startup. P0050 sets when the heater's resistance or current is out of range, or the PCM cannot control the circuit properly. Bank 2 is the side of the engine that does not contain cylinder 1.

Symptoms

  • Check Engine light on
  • Worse fuel economy
  • Rough or unstable idle, mostly when cold
  • Longer time to enter closed-loop operation
  • Higher emissions or a failed emissions test

Possible causes

  1. Failed heater element inside the Bank 2 Sensor 1 oxygen sensor
  2. Damaged wiring or corroded connector in the heater circuit
  3. Blown fuse or loss of power to the heater circuit
  4. Poor ground or a PCM driver fault
  5. Faulty heater relay, on vehicles that use one

How to diagnose

  1. Scan for codes and freeze-frame data and look for other O2 sensor codes
  2. Confirm which sensor is Bank 2 Sensor 1 (the side without cylinder 1, before the catalytic converter)
  3. Inspect the sensor harness and connector for chafing, melting or corrosion
  4. Check the heater fuse and relay
  5. Measure the sensor heater resistance and compare it with the spec for your vehicle
  6. Check for power and the control signal at the connector using the wiring diagram
  7. Test the wires for opens and shorts to ground back to the PCM
  8. Review live sensor data and fuel trims, and check for exhaust leaks near the sensor

Common fixes

  • Replace the Bank 2 Sensor 1 oxygen sensor
  • Repair the wiring or connector in the heater circuit
  • Replace the fuse or relay after finding why it failed
  • Repair a poor ground connection
  • Repair or replace the PCM in rare cases

P0050 on different brands

Ford · manuals
On Ford, the extended code P0050:1E refers to the Bank 2 heater resistance monitor and shows which condition the monitor detected, not a confirmed failed part.

Questions and answers

Can I drive with a P0050 code?

Usually yes, the car will run, but fuel economy and emissions get worse. Have it diagnosed soon.

What does Bank 2 Sensor 1 mean?

It is the oxygen sensor ahead of the catalytic converter on the side of the engine that does not have cylinder 1. It is found on V-type and flat engines.

Do I always need a new sensor for P0050?

No. Check the fuse, connector, wiring and heater resistance first. Replace the sensor if its heater element is bad.

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.