O2 Sensing Error By Means of Short Test, Bank 1 - Below Limit

P1127

418 Oxygen Sensing Error By Means of Short Test, Bank 1 - Below Limit

Diagnosis conditions
- Mixture adaptation performed with the Porsche System Tester 2

Possible fault cause
- Incorrect signal from MAF sensor
- Fuel pressure too high
- Fuel injector leaking
- EVAP canister purge valve open

Affected terminals
- (none)

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.

Work Instruction 1 - 5: