P1172
Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)
Symptoms
- Check Engine light comes on
- Increased fuel consumption
- Reduced engine power
- Unstable engine operation at idle
Causes
- A/F sensor malfunction
- Open or short circuit in the sensor circuit
- Poor contact in the sensor connector
- ECU malfunction
- Air leak in the intake tract
How to Fix
- Check the integrity of the sensor wiring
- Check the contacts in the sensor connector
- Clean sensor contacts
- Replace A/F sensor if necessary