P0171
P0171
Diagnosis information - DME V8 DFI
Lambda control adaptation bank X: system too lean
NOTE:
- Diagnosis should indicate a positive deviation of more than 30% (enrichment) of the lambda control adaptation.
- The most frequent causes of faults are leaks (secondary air) between the throttle and intake valves or at the engine ventilation.
- Opposed adaptation values in connection with misfires indicate that the timing is out of adjustment.
Diagnostic conditions
- Lambda control active
2010 Porsche Cayenne Turbo (9PA) V8-4.8L Turbo Page 26
- Lambda control adapted
- Tank vent closed
- Engine temperature > 60 °C (140 °F)
- Intake air temperature < 80 °C (176 °F)
- Engine running > 45 seconds at engine speed < 800 rpm
- then driving at varying load ranges and engine speeds between 1,060 rpm ... 2,490 rpm
Possible fault causes
- Incorrect main filling signal from hot-film mass air flow sensor
(setpoint voltage with stopped engine and ignition on = 0.9 ... 1.1 V)
- Oil filler cap leaking
- Crankcase ventilation leak
- Intake system leaks
- Mechanical fault of tank vent (stuck open)
- Tank vent driver fault
- Leak in exhaust system
- Mechanical fault of fuel injector(s)
- Wrong fuel high-pressure signal
- Timing incorrectly adjusted