P1166
Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)
Symptoms
- Check Engine light comes on
- Increased fuel consumption
- Unstable engine operation at idle
- Reduced engine power
- Increased level of harmful emissions
Causes
- Air/fuel ratio sensor malfunction
- Open or short circuit in the sensor heating circuit
- Damage to the sensor wiring harness
- Heating circuit fuse or relay failure
- Problems with the engine control unit (ECU)
How to Fix
- Check the condition of the sensor and its connector
- Check the integrity of the sensor heating circuit
- Check the fuse and relay of the heating circuit
- Replace the faulty sensor if necessary
- Check the operation of the engine control unit