What it means
The control circuit for the heater in the Bank 1 Sensor 1 heated oxygen sensor has a malfunction.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The upstream oxygen sensor before the catalytic converter on bank 1 has an electric heater that helps it reach operating temperature quickly. The engine control module monitors the heater circuit and sets P0030 when that circuit does not operate as expected, delaying accurate exhaust feedback and potentially increasing emissions and fuel use.
Common causes
Most likely first.
- Heater element open or burnt out
- Heater supply fuse blown
- Wiring or connector fault
Symptoms
- Check engine light on
- Increased emissions
- Reduced fuel economy
- Failed emissions test
How to diagnose it
- Save freeze-frame data and check for other oxygen-sensor or heater codes to see whether the fault affects only bank 1 sensor 1.
- Locate the upstream bank 1 sensor before the catalytic converter and inspect its connector and heat-exposed wiring for damage or disconnection.
- Check the heater fuse and related power supply using the vehicle's wiring information, since a blown fuse can disable the sensor heater.
- Test the sensor heater circuit for continuity and check its supply and control wiring according to the manufacturer's procedure.
- If the wiring and fuse are sound, test the bank 1 sensor 1 heater and module control to identify the failed component.
Common fixes
- Reconnect the bank 1 sensor 1 plug or secure its wiring if loose.
- Replace a blown heater fuse after checking for a short that caused it to fail.
- Repair damaged heater-circuit wiring or connector terminals.
- Replace the bank 1 sensor 1 oxygen sensor if its heater has failed internally.
Can I keep driving?
Usually the vehicle can be driven if it runs normally, but cold-start emissions may rise and fuel economy can suffer. Arrange repair soon, especially if an emissions test is due or other drivability symptoms appear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.