P0036 Oxygen sensor heater control circuit (bank 1, sensor 2)
What P0036 means
The engine computer has detected a fault in the heater circuit of the downstream oxygen sensor on bank 1, the sensor after the catalytic converter. This sensor mainly monitors how well the catalytic converter works, so the engine usually runs normally, but the catalyst check cannot be completed.
P0036 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 80–350 €
- Workshop time
- 0.5–1.5 h
- Repair difficulty
- Easy
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Usually no change in how the car drives
- Catalyst and oxygen sensor readiness monitors not completing
- Possible failed emissions test at inspection
Common causes
- Burnt-out heater element in the downstream oxygen sensor
- Blown fuse or faulty relay in the heater supply
- Damaged wiring or corroded connector under the car
- Engine control unit heater driver fault (rare)
Can I keep driving with P0036?
You can keep driving, but have it checked within a week or so. It does not harm the engine, but the car is likely to fail an emissions inspection until it is repaired.
What to check first
- Check the oxygen sensor heater fuse and note any other O2 sensor codes stored with it.
- Inspect the downstream sensor wiring for damage from road debris, heat or corrosion at the connector.
- Measure the heater resistance at the sensor connector and compare it with the specification; an open circuit means a failed heater.
- Check for battery voltage on the heater supply with the key on. If the wiring is good, replace the downstream oxygen sensor.
Related codes
- P0037 Oxygen sensor heater control circuit low (bank 1, sensor 2)
- P0038 Oxygen sensor heater control circuit high (bank 1, sensor 2)
- P0030 Oxygen sensor heater control circuit (bank 1, sensor 1)
- P0045 Turbocharger/supercharger boost control A circuit/open
- P0021 Intake (A) camshaft timing over-advanced or system performance (bank 2)
- P0020 Intake (A) camshaft position actuator circuit/open (bank 2)
- P0019 Crankshaft/camshaft position correlation, bank 2 sensor B (exhaust)
- P0018 Crankshaft/camshaft position correlation, bank 2 sensor A (intake)
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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