10AA21

10AA21 - P10D4

Information saved in
DME

Fault code
10AA21 - P10D4

Fault text
Coolant temperature sensor, cold start: Coolant temperature
too low

Fault description
The diagnostic function monitors the coolant temperature to
detect excessively low values during cold starts.

Condition for fault identification
Test condition:
The fault is recognized when the coolant temperature is
18 °C below the average of several temperatures at cold start.
Potential problem source(s):
- Defect in wiring harness between DME and sensor
- Sensor defective
- Defective DME
Terminal condition: none
Voltage condition:
- Onboard electrical system voltage between 9 V and 16 V
Temperature condition:
- None
Time condition:
- 21 sec. after engine start
Other conditions:
- Cold engine start

Condition for fault memory entry
This fault is logged in the control module's fault memory
immediately.

Action in service
- Check wiring harness between DME and sensor
- Replace sensor
- Replace DME

Fault effect and breakdown warning
Breakdown notice:
None
Possible apparent symptoms:
Rough engine, possibly followed by power reduction caused
by thermal management

Driver information
Warning light:
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
None