P0174

P0174

Diagnosis Information - DME (DFI)

Lambda control adaptation, bank 2: system too lean

NOTE:
- At idle speed, the diagnosis should indicate a positive deviation (enrichment) of more than 3.3 mg/stk of the lambda control adaptation.
- In the lower and upper load ranges, the diagnosis should indicate a positive deviation (enrichment) of more than 30% of the lambda control adaptation.
- Opposed adaptation values in connection with misfires indicate that the timing is out of adjustment.
- If the fault was entered due to an open oil filler cap with the engine running (e.g. for topping up oil), then an event was also entered in the instrument cluster (event memory) at the same time:
- see Instrument cluster
- Event memory
- if entry "A017 Rear lid open while driving" is present:
- see Extended fault memory
- Distance (in kilometers or miles, depending on units setting in instrument cluster)
- Convert miles to kilometers if necessary (x 1.609)
- Compare kilometer value with:
- DME (DFI)
- Fault memory
- P0174 Lambda control adaptation, bank 2: system too lean
- Extended fault memory
- Distance driven (first error)
- Kilometer value

If the two kilometer values from the instrument cluster and DME (DFI) are approximately the same, the faults P0171 + P0174 were entered while the oil filler cap was open with the engine running.

see Driver's Manual

Diagnostic conditions
- Lambda control active
- 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
- Oil filler cap was opened while engine was running (e.g. to top up oil)
- Oil filler cap leaking
- Crankcase ventilation leak
- Intake system leak
- Mechanical fault of tank vent (stuck open)
- Tank vent driver fault
- Leak in exhaust system
- Changed flow to the mass air flow sensor (e.g. due to wrong air cleaner insert or wrong air cleaner housing)
- Incorrect main filling signal from hot-film mass air flow sensor
- Mechanical fault of fuel injector(s)
- Wrong fuel high-pressure signal
- Timing incorrectly adjusted