P0030 Oxygen sensor heater control circuit (bank 1, sensor 1)
What P0030 means
The engine computer cannot properly control the heater inside the upstream oxygen sensor on bank 1 (the sensor before the catalytic converter). Without the heater the sensor takes much longer to start working after a cold start, so the engine runs on a fixed fuel map for longer than it should.
P0030 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
- Slightly higher fuel consumption, mostly on short trips
- Emissions readiness monitors not completing
- Possible failed emissions test at inspection
Common causes
- Burnt-out heater element inside the oxygen sensor
- Blown fuse or faulty relay supplying the sensor heater
- Damaged or melted wiring near the exhaust, or a corroded connector
- Engine control unit heater driver fault (rare)
Can I keep driving with P0030?
You can keep driving, but have it checked within a week or so. Fuel consumption and emissions rise slightly, and the car may fail its emissions test until it is fixed.
What to check first
- Check the fuse for the oxygen sensor heater circuit and look for other O2 heater codes stored at the same time.
- Inspect the sensor wiring and connector for melted insulation, chafing on the exhaust or green corrosion.
- Unplug the sensor and measure the heater resistance across the heater pins; compare it with the specification. An open circuit means the heater has burnt out.
- With the key on, check for battery voltage on the heater supply wire. If supply and wiring are good and the heater is open, replace the oxygen sensor.
Related codes
- P0036 Oxygen sensor heater control circuit (bank 1, sensor 2)
- P0037 Oxygen sensor heater control circuit low (bank 1, sensor 2)
- P0038 Oxygen sensor heater control circuit high (bank 1, sensor 2)
- P0021 Intake (A) camshaft timing over-advanced or system performance (bank 2)
- P0020 Intake (A) camshaft position actuator circuit/open (bank 2)
- P0045 Turbocharger/supercharger boost control A circuit/open
- 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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