P0030
HO2S Heater Control Circuit Bank 1 Sensor 1
The engine computer has found a problem in the heater circuit for the upstream oxygen sensor on bank 1. The sensor heater may not be getting power, ground, or the sensor itself may be bad. This can cause poor fuel control, a check engine light, and slower sensor response.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20–$180
- SHOP
- $120–$450
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Failed upstream oxygen sensor heater element in Bank 1 Sensor 1
- Blown fuse or failed relay feeding the oxygen sensor heater circuit
- Damaged, melted, or corroded wiring or connector at the sensor
Typical repair cost
DIY usually runs $20–$180. Typical shop repair lands around $120–$450, depending on the root cause.
01 / Definition
P0030 means the powertrain control module detected an electrical fault in the heater circuit for the Bank 1 Sensor 1 heated oxygen sensor. This is the upstream O2 sensor before the catalytic converter on the side of the engine with cylinder 1. The fault may be caused by an open circuit, short circuit, blown fuse, damaged wiring, corrosion, or a failed sensor heater element.
02 / Drive status
With caution. The vehicle usually can be driven for a short time, but fuel economy and emissions may suffer. If the engine runs rough, stalls, or other warning lights appear, diagnose it soon.
03 / Symptoms
- Check engine light on
- Reduced fuel economy
- Rough cold-start operation
- Higher emissions
- Possible delayed closed-loop operation
- No obvious drivability symptoms in some cases
04 / Causes
| 1 | Failed upstream oxygen sensor heater element in Bank 1 Sensor 1 | high |
|---|---|---|
| 2 | Blown fuse or failed relay feeding the oxygen sensor heater circuit | high |
| 3 | Damaged, melted, or corroded wiring or connector at the sensor | high |
| 4 | Poor ground or open circuit in the heater power supply | medium |
| 5 | PCM driver fault or control circuit issue | low |
05 / Diagnostic sequence
- 01Verify the code and check for related O2 sensor or heater circuit codes.
- 02Inspect the Bank 1 Sensor 1 wiring and connector for heat damage, corrosion, looseness, or broken wires.
- 03Check the oxygen sensor heater fuse and relay, if equipped.
- 04Use a scan tool to monitor O2 sensor heater operation and look for sensor response after cold start.
- 05Measure heater circuit power, ground, and sensor resistance with a multimeter.
- 06Repair any wiring faults, then clear codes and retest.
- 07If power and ground are correct and the code returns, replace the Bank 1 Sensor 1 oxygen sensor.
- 08If the fault remains after sensor replacement, test the PCM control circuit and related wiring.
06 / Repairs
| 1 | Repair damaged wiring, connectors, or terminals in the heater circuit | $20–$150 |
|---|---|---|
| 2 | Replace blown fuse or faulty relay if the heater circuit lost power | $10–$60 |
| 3 | Replace the Bank 1 Sensor 1 upstream oxygen sensor | $50–$250 |
| 4 | Diagnose and repair PCM control circuit faults if wiring and sensor test good | $150–$600 |
07 / Related codes
08 / FAQ
What is Bank 1 Sensor 1?
It is the upstream oxygen sensor on the side of the engine with cylinder 1, located before the catalytic converter.
Can a bad oxygen sensor heater cause poor gas mileage?
Yes. If the heater does not work, the engine may stay in open loop longer and use more fuel.
Will replacing the oxygen sensor always fix P0030?
No. Wiring damage, fuse problems, or a bad relay can also cause this code.
Is P0030 the same as an O2 sensor performance code?
No. P0030 is a heater circuit fault, not a sensor signal or mixture performance fault.
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.