U1170

20AA04 - U1170

Information saved in
DME

Fault code
20AA04 - U1170

Fault text
Coolant pump, communication: malfunction

Fault description
The diagnostic function monitors BSD bus communications
with the electric water pump.

Condition for fault identification
Test condition:
The fault is recognized when the water pump fails to
transmit messages.
Potential problem source(s):
- Voltage supply defect
- Defective BSD wire
- Defective wiring harness
- Defective water pump
Terminal condition: Terminal 15
Voltage condition:
- Electrical system voltage > 10 V
Temperature condition:
- None
Time condition:
- None
Other conditions:
- none

Condition for fault memory entry
This fault is logged in the control module's fault memory if
it remains present for longer than 10 sec.

Action in service
- Check wiring harness
- Replace water pump

Fault effect and breakdown warning
Breakdown notice:
- none
Possible apparent symptoms:
- Engine can overheat

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

Service instruction
- none