HO2S Heater Control Circuit High Bank 1 Sensor 2
What it means
P0038 means the ECM detected high voltage (an open or high-resistance) in the heater control circuit of the bank 1, sensor 2 oxygen sensor — the downstream sensor after the catalytic converter. The heater brings the sensor up to operating temperature quickly; when its circuit faults, the car still drives normally but the check-engine light stays on and emissions monitors may not complete.
Can I keep driving? Yes — the car drives normally; this affects the downstream O2 sensor's heater, so the main effects are a warning light, slower emissions readiness, and a likely emissions-test failure.
Common symptoms
What you'll notice
- Check-engine light on
- Fails or won't complete an emissions/readiness test
- Slightly reduced fuel economy in some cases
- Often no noticeable change in how the car drives
Common causes
Most likely first
- Open or high-resistance in the bank 1 sensor 2 O2 heater circuitLikely
- Failed heater element inside the downstream oxygen sensorCommon
- Corroded or loose connector at the sensorCommon
- Damaged wiring or a blown heater fuseLess often
- Faulty ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the code names bank 1, sensor 2 (downstream).
- Inspect the sensor connector and wiring for corrosion, melting near the exhaust, or a loose pin.
- Check the O2 heater fuse and confirm power reaches the sensor.
- Measure the sensor's heater resistance and compare to spec.
- Replace the downstream oxygen sensor if the heater element is open or out of range.
- Clear the code and drive a full cycle to confirm it stays off.
FAQ
Quick answers
Is it safe to drive with P0038?+
Can I just clear P0038?+
Related codes
Often seen with P0038
Read & clear P0038 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.