Engine and gearbox (P)
P0037: O2 Sensor Heater Circuit Low Voltage
The oxygen sensor heater control circuit for Bank 1, Sensor 2 is reporting low voltage. This can prevent the sensor from reaching its operating temperature, affecting fuel mixture adjustments.
Checked by a licensed car technician · last reviewed 30 September 2026
Symptoms
- Increased fuel consumption
- Rough idling
- Poor engine performance
- Check engine light on
Common causes
- Heater wire shorted to ground
- Corroded connector pins
- Chafed harness insulation
How to check it yourself
- Inspect the wiring for visible damage
- Check the connector for corrosion
- Test the heater circuit with a multimeter
Can I keep driving?
The car can still be driven, but fuel efficiency and performance may be reduced.
General guidance, not a professional inspection. Confirm faults with measurements before buying parts, and use a qualified mechanic for brakes, steering, fuel leaks, airbags, and other safety-critical work. Terms and disclaimer