OBD-II Code · Sensors
P0030
O2 Sensor Heater Control Circuit (B1S1)
Severity
low
Lowest on our scale. Fix it when convenient.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$150–$350
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
O2 heater control fault, bank 1 sensor 1.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Likely causes
- Failed heaterMost common
- Wiring
Read the full diagnostic procedureP0030 sets when the PCM cannot confirm activity on the heater control circuit for the upstream oxygen sensor on Bank 1 — typically the side of the en…
P0030 sets when the PCM cannot confirm activity on the heater control circuit for the upstream oxygen sensor on Bank 1 — typically the side of the engine containing cylinder #1. The PCM pulse-width-modulates the ground side of the heater while feeding battery voltage on the supply side, monitoring for the expected current draw and voltage drop.
Start with the cheapest test
with the sensor cold and disconnected, measure heater resistance pin-to-pin at the sensor side of the connector. A narrowband should read roughly 2-10 ohms cold (most Bosch and Denso units land at 3-6 ohms); open circuit means a blown heater element inside the sensor. Key-on engine-off, back-probe the supply pin for battery voltage (should be within 0.3V of battery), then scope the ground-side PWM during the first 60 seconds of run time — duty cycle ramps from roughly 10% up toward 90% as the sensor warms. Expect 0.5-2A of heater current at peak warm-up and closed-loop entry inside 30-90 seconds. The expensive misdiagnosis is replacing the sensor when the actual fault is a chafed wire to the heater fuse, a corroded PCM driver pin, or a blown heater fuse shared with multiple sensors — always confirm the supply side before condemning a $90-$250 sensor.
Vehicle-specific patternsGM 5.3L and 6.0L LS trucks (Silverado/Sierra/Tahoe 2003-2014) chronically chafe the upstream O2 harness against the exhaust manifold heat-shield bolt…
GM 5.3L and 6.0L LS trucks (Silverado/Sierra/Tahoe 2003-2014) chronically chafe the upstream O2 harness against the exhaust manifold heat-shield bolt, melting insulation and shorting heater feed to ground — GM TSB 04-06-04-038 covers re-routing and a shielded pigtail.
- 2007-2017Toyota Camry and Tacoma with the 2GR-FE V6 lose the B1S1 wideband AFR sensor (Denso 234-9051) to internal heater-element fatigue around 90-120K miles, usually presenting as P0031 first then escalating to P0030. Honda K24 (Accord/CR-V/Element 2003-2012) narrowband heaters simply age out past 150K miles with no harness fault present. Ford 5.4L 3V Triton (F-150/Expedition 2004-2010) suffers connector-pin corrosion at the upstream sensor where the harness routes near the cowl drain — a dielectric-grease repair often clears the code without a sensor.
Estimated repair$90 to $450.
Look up another code
P0030 — frequently asked
What does a P0030 code mean?
O2 heater control fault, bank 1 sensor 1.
What causes a P0030 code?
Common causes: Failed heater; Wiring.
What are the symptoms of a P0030 code?
Typical symptoms: Check engine light.
Is it safe to drive with a P0030 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $150-$350.
How do I diagnose a P0030 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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