P0050
HO2S Heater Control Circuit (Bank 2 Sensor 1)
The engine computer found a problem in the heater circuit for the front oxygen sensor on bank 2. That heater helps the sensor warm up quickly so fuel control can go into closed loop. When the circuit fails, the light comes on and cold-start fuel control can suffer.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20-$160
- SHOP
- $120-$450
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Failed Bank 2 Sensor 1 oxygen sensor heater element
- Damaged wiring, melted insulation, or poor connector contact near the sensor
- Blown fuse or failed relay feeding the oxygen sensor heater circuit
Typical repair cost
DIY usually runs $20-$160. Typical shop repair lands around $120-$450, depending on the root cause.
01 / Definition
P0050 means the PCM detected an electrical fault in the heater control circuit for the Bank 2 Sensor 1 heated oxygen sensor. Bank 2 Sensor 1 is the upstream sensor on the side of the engine that does not contain cylinder 1. The fault is usually caused by an open or shorted heater circuit, failed heater element, blown fuse, damaged wiring, or a control-side problem.
02 / Drive status
With caution. You can usually drive for a short time, but fuel economy, cold-start performance, and emissions may get worse. Diagnose it soon, especially if the engine runs rough or more oxygen-sensor codes appear.
03 / Symptoms
- Check engine light on
- Reduced fuel economy
- Rougher cold starts
- Delayed closed-loop operation
- Failed emissions test
04 / Causes
| 1 | Failed Bank 2 Sensor 1 oxygen sensor heater element | high |
|---|---|---|
| 2 | Damaged wiring, melted insulation, or poor connector contact near the sensor | high |
| 3 | Blown fuse or failed relay feeding the oxygen sensor heater circuit | high |
| 4 | Open circuit or poor ground on the heater power supply side | medium |
| 5 | PCM driver or control circuit fault | low |
05 / Diagnostic sequence
- 01Verify P0050 and scan for related heater, signal, and fuel-trim codes.
- 02Inspect Bank 2 Sensor 1 wiring and connector for heat damage, corrosion, loose pins, or broken insulation.
- 03Check the O2 heater fuse and relay, and confirm battery voltage reaches the heater circuit.
- 04Measure heater resistance at the sensor and compare it with service-manual specifications.
- 05Check the control side for an open circuit, short to power, or short to ground.
- 06Repair wiring faults, clear the code, and verify heater operation on a cold start.
- 07Replace the sensor only after power, ground, and harness checks are completed.
06 / Repairs
| 1 | Repair damaged heater-circuit wiring, connector pins, or terminals for Bank 2 Sensor 1 | $20-$150 |
|---|---|---|
| 2 | Replace a blown fuse or failed relay after confirming why the heater circuit lost power | $10-$80 |
| 3 | Replace the Bank 2 Sensor 1 oxygen sensor if the heater element is open or out of specification | $60-$260 |
| 4 | Diagnose PCM driver faults if the sensor and external wiring test good | $150-$600 |
07 / Related codes
08 / FAQ
What is Bank 2 Sensor 1?
It is the upstream oxygen sensor on the side of the engine that does not contain cylinder 1.
Will a bad heater circuit affect how the engine runs?
It often affects cold-start fuel control and emissions more than warm drivability, but rough running and poor mileage can still happen.
Does P0050 always mean the sensor is bad?
No. Wiring damage, a blown fuse, or a failed relay can trigger the same code.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.