P1143
Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)
Symptoms
- Increased fuel consumption
- Reduced engine power
- Unstable engine idling
- Check Engine Light Is On
- Dips during acceleration
Causes
- Air leak in the intake tract
- Malfunction of the mass air flow sensor (MAF)
- Dirty or faulty oxygen sensor
- Problems with the fuel pump or injectors
- Vacuum system leaking
How to Fix
- Check the intake tract for air leaks
- Check the serviceability of the mass air flow sensor and clean or replace if necessary
- Check the condition of the oxygen sensor and its wiring
- Check fuel pressure and condition of fuel injectors
- Check vacuum hoses for leaks