HO2S Heater Control Circuit Bank 1 Sensor 2
What it means
P0036 means the ECM found a fault in the heater control circuit of the bank 1, sensor 2 oxygen sensor — the downstream sensor after the catalytic converter. The built-in heater brings the sensor up to operating temperature quickly; when its circuit fails, the sensor reads late or not at all. The engine still runs fine, but emissions monitoring is degraded.
Can I keep driving? Safe to drive — the engine runs normally, but the downstream oxygen sensor can't warm up properly, so emissions monitoring is affected and it will fail an emissions test.
Real-world scan data
Appears alongside · share of P0036 scans
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on
- Often no noticeable change in how the car drives
- Failed or incomplete emissions readiness monitor
- Slightly reduced fuel economy in some cases
Common causes
Most likely first
- Failed heater element inside the bank 1 sensor 2 (downstream) oxygen sensorLikely
- Blown fuse or open in the heater power feedCommon
- Damaged wiring or corroded connector at the sensorCommon
- Poor ground or loose connection in the heater circuitLess often
- Faulty engine control module (ECM), rarelyLess often
How to diagnose & fix
Work through it in order
- Locate the bank 1 sensor 2 oxygen sensor (downstream, after the catalytic converter).
- Check the heater circuit fuse and the sensor connector for corrosion or damage.
- Measure the sensor's heater resistance and supply voltage against spec.
- Repair wiring or replace the oxygen sensor if the heater element has failed.
- Clear the code and drive a full cycle to confirm the monitor completes.
FAQ
Quick answers
Is it safe to drive with P0036?+
Can I just clear P0036?+
Related codes
Read & clear P0036 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.