OBD-II · Engine and powertrain (P)
P0050
Oxygen sensor heater control circuit bank 2 sensor 1
What it means
The ECU detects a fault in the circuit it uses to switch the heater of the upstream (before the catalytic converter) lambda sensor on bank 2. Confirm bank 2's location in the engine's service information.
Symptoms
- engine warning light
- slightly higher fuel consumption and emissions after a cold start
- usually no change in how the car drives
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | failed heater element inside the sensor |
| 02 | blown fuse or missing power feed |
| 03 | wiring damage near the exhaust |
| 04 | connector corrosion |
| 05 | ECU driver fault |
What to check, step by step
- 01Check the fuse and relay that feed the lambda sensor heaters
- 02Inspect the connector and wiring along the exhaust
- 03Measure the heater resistance at the sensor and compare with specification
- 04Check the heater control wire between the sensor and the ECU for opens and shorts
- 05Replace the sensor if the heater element is faulty