2EF4

2EF4 - P0128

Information saved in
DME

Fault code
2EF4 - P0128

Fault text
Map thermostat, mechanism

Fault description
Coolant Thermostat (Coolant Temperature Below
Thermostat Regulating Temperature)

Condition for fault identification
Test condition:
Engine's warm-up performance monitored by comparing
measured coolant temperature with modeled coolant
temperature to detect defective coolant thermostat
Diagnosis conditions:
- Engine temperature < 65 �C
- Vehicle speed between 10 and 90 km/h
- Engine speed > 800 rpm
- Ambient temp. > -8 �C
Terminal condition: Engine running
Voltage condition:
Varies according to battery voltage

Condition for fault memory entry
With all diagnosis-activation conditions and fault criterion
present ( =diff. coolant temp. from model - sensor value >
threshold) fault logged after 15 sec.

Action in service
Replace thermostat

Fault effect and breakdown warning


Driver information
Warning light:
MIL on (in 2nd driving cycle) in US version only

Service instruction
none