P1151
Lack Of HO2S21 Switch - Sensor Indicates Lean
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$17–67 (est.)
Symptoms
- Increased fuel consumption
- Reduced engine power
- Unstable idling
- Check Engine Light Is On
- Dips during acceleration
Causes
- Vacuum leak
- Oxygen sensor malfunction (HO2S21)
- Problems with the fuel pump or injectors
- Sensor wiring harness is dirty or damaged
- Air intake system malfunction
How to Fix
- Check for vacuum leaks
- Check the condition of the oxygen sensor and its wiring harness
- Check the operation of the fuel pump and injectors
- Clean or replace the oxygen sensor if necessary
- Check the air intake system for blockages