118F20 - P2177 (DME)

118F20 - P2177

Information saved in
DME

Fault code
118F20 - P2177

Fault text
Mixture adaptation, lower speed range: mixture at part load
too lean

Fault description
The diagnostic function monitors the mixture adaptation.

Condition for fault identification
Test condition:
The fault is recognized when the mixture is too lean and
must be enriched by more than 25-30%, depending on load
factor.
Potential problem source(s):
- Oxygen sensor before catalytic converter defective
- Mass-airflow sensor defective
- Defective injectors
- Intake-manifold pressure sensor defective
- Intake-air temperature sensor defective
- Camshaft position sensor defective
- Defect in high-pressure fuel system
- Defect in low-pressure fuel system
- Intake system leaking
- Oil cap not sealing
- Leak in exhaust system before oxygen sensor behind
catalytic converter
- Poor-quality gasoline
Terminal condition: none
Voltage condition:
- Onboard electrical system voltage between 9 V and 16 V
Temperature condition:
- None
Time condition:
- None
Other conditions:
- Engine on
- EVAP not active

Condition for fault memory entry
The diagnostic fault code is logged when the fault remains
present for longer than 1 min.

Action in service
- If additional faults related to the following components are
present, process these first: Pre-catalyst oxygen sensor,
mass-airflow sensor, intake-manifold pressure sensor,
intake-air temperature sensor, camshaft position sensor,
high-pressure fuel system, low-pressure fuel system Check
air-induction system for leaks (also checking the following
components: Positive crankcase ventilation, oil cap, tank
evaporative emissions system)
- Check exhaust system for leaks
- Replace injectors

Fault effect and breakdown warning
Breakdown notice:
- Loss of power
Possible apparent symptoms:
- Engine runs poorly

Driver information
Warning light:
- ECE emissions warning lamp: on
- ECE electronic engine power reduction: on
- CC message: on
- US emissions warning lamp: off
- US electronic engine power reduction: off
- CC message: none

Service instruction
- Delete mixture adaptations following repair