P1272
Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected
Severity
🔴 HighCan you drive?
Limited driving only, diagnose soon
Approx. repair cost
$33–167 (est.)
Symptoms
- Check Engine light comes on
- Reduced engine power
- Increased fuel consumption
- Unstable engine idling
- The car may go into emergency mode
Causes
- Air-fuel ratio sensor malfunction
- Open or short circuit in the sensor circuit
- Poor connection or corrosion in connectors
- Engine control unit (ECU) malfunction
- Problems with power or grounding of the sensor
How to Fix
- Check the integrity of the sensor circuit (breaks, short circuits)
- Inspect the sensor connectors for corrosion or damage.
- Check the power supply and grounding of the sensor
- Replace faulty air-fuel ratio sensor
- If necessary, reflash or replace the engine control unit