- Incorrect signal from MAF sensor
- Fuel pressure too high
- Fuel injector leaking
- EVAP canister purge valve open
Diagnosis/troubleshooting
NOTE: If DTC P0445 (fuel tank vent valve - short to ground) is stored, correct this fault first. An open EVAP canister purge valve can lead to
the lean threshold being reached.
Part 1
Part 2
Oxygen Sensing Error By Means of Short Test, Bank 1 - Below Limit
P1127
418 Oxygen Sensing Error by means of Short Test, Bank 1 - Above Limit
Diagnosis conditions
- Mixture adaptation performed with the Porsche System Tester 2
Possible fault cause
- Incorrect signal from MAF sensor
- Intake air system leaking
- Fuel pressure too low
- Volume supply of fuel pump too low
- Fuel injectors fouled