
This instruction show you guide on how to solve Liebherr machine ECU2 ECU2-HD ECU3,D9505 D9512 D967 D9508 D966 engine fault code P1166 critical over temperature.
Related Contents:
Liebherr LIDIA 2026 Diagnostic Software
Reason:
DEF temperature is too high on DEF pump

Troubleshooting:
The sensor is working correctly, the measured temperature is higher than a threshold.
Do not exchange the sensor.
Check water valves
Proper operation
Flow direction
Proper electrical connections
In case of 2 SCR systems, proper installation of both systems (no inversion between systems)

Consequence:
As the P1166-00 failure is only at information level, the system is operating properly
If failure still occurs after troubleshooting, please do not exchange parts before any contact with your local partner.

BMK:

Component location
EATS All version
D9512 A7 04-05-StageV

Primary (A700)

Secondary (A760)

























