1D2008

1D2008 - P0128

Information saved in
DME

Fault code
1D2008 - P0128

Fault text
Map thermostat, mechanical: jammed open

Fault description
The diagnostic function monitors the rise in coolant
temperature at the engine's discharge connection.

Condition for fault identification
Test condition:
A fault is recognized when the engine temperature is below
80 °C when the test is executed. Because the test time is
defined by the temperature model, it is also determined by
the model's input variables (air mass, ambient temperature
and model temperature).
Potential problem source(s):
- Defective wiring harness
- Characteristic map thermostat defective
Terminal condition: none
Voltage condition:
- Onboard electrical system voltage between 9 V and 16 V
Temperature condition:
- Coolant temperature sensor less than 40 °C
Time condition:
- None
Other conditions:
- Engine cold start
- Vehicle speed in excess of 30 km/h
- Ambient temperature higher than minus 10 °C
- Engine speed between 800 rpm and 7000 rpm

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

Action in service
- Check wiring harness
- Replace map-controlled thermostat

Fault effect and breakdown warning
Breakdown notice:
None
Possible apparent symptoms:
- The output of the interior heater may be reduced.

Driver information
Warning light:
MY10 ECE:
- ECE emissions warning lamp: off
- ECE electronic engine power reduction: off
- CC message: none
MY10 US:
- US emissions warning lamp: on
- US electronic engine power reduction: off
- CC message: on

Service instruction
- When the engine is heated from external sources, such as
an auxiliary heater, diagnosis errors can result!