P0174

P0174

Diagnosis information - DME (DFI)

Lambda control adaptation, bank 2: system too lean

NOTE:
- At idle speed speed, the diagnosis should indicate a positive deviation (enrichment) , of more than 3.3 mg/Stroke of the lambda control adaptation.
- In the lower and upper load ranges ranges, 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.

NOTE:
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:
--> Event memory

- if entry [A017 Rear lid open while driving] is present:
--> [Distance] (in kilometers or miles, depending on units setting in instrument cluster)
- Convert miles to kilometers if necessary
(miles x 1.609 = kilometers)
(kilometers / 1.609 = miles)

- 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.

Diagnostic conditions
- Lambda control active
- Lambda control adapted
- Tank vent closed
- Engine temperature more than 60 °C (140 °F)
- Intake air temperature less than 80 °C (176 °F)
- Engine running more than 45 seconds at engine speed less than 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) --> See NOTE.
- Incorrect main filling signal, hot-film mass air flow (MAF) sensor soiled/faulty (displaced characteristic)
(setpoint voltage with stopped engine and ignition on = 0.9 ... 1.1 V
--> see Actual values, Filter [H_Mass air flow], [H030_Mass air flow sensor 1 (sensor)])
- 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
- Changed flow to the mass air flow sensor (e.g. due to wrong air cleaner insert or wrong air cleaner housing)
- Mechanical fault of fuel injector(s)
- Wrong fuel high-pressure signal
- Timing incorrectly adjusted