P15D4

20A901 - P15D4

Information saved in
DME

Fault code
20A901 - P15D4

Fault text
Coolant pump, operation with reduced output: Dry running
detected

Fault description
The diagnostic function monitors the electric water pump for
cavitation.

Condition for fault identification
Test condition:
The fault is recognized when the electric water pump
recognizes cavitation.
Potential problem source(s):
- Coolant loss, leak in cooling system
- Air in the cooling system
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
- No BSD fault

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 cooling system for leaks
- Refill and then bleed cooling system as indicated
- If the fault continues to appear although the cooling system
is bled and no leaks are present, replace the water pump.

Fault effect and breakdown warning
Breakdown notice:
None
Possible apparent symptoms:
CC message if engine becomes too hot, breakdown in
extreme cases

Driver information
Warning light:
- ECE emissions warning lamp: off
- ECE electronic engine power reduction: off
- CC message: on
- US emissions warning lamp: off
- US electronic engine power reduction: off
- CC message: on

Service instruction
Observe sequence for fault rectification:
- If the pump is activated at TMOT>90 °C as tester job the
diagnostic fault code 0x3792 or 0x20AD08 'Water pump:
rotation speed implausible' can be logged, ignore this fault
and delete it --> Carry out tester job at Tmot<90 °C