4.2.256. SPN 521002, FMI 31, DEF pump direction valve high side control powerstage over temperatureΒΆ

Description

EEM4 monitoring system has detected over temperature on DEF pump direction valve high side.

Possible causes are:

  • The DEF supply module wiring is defective.
  • The DEF supply module is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated. The CAN message indicates active fault.

NOTE: The present fault is classified as an emission related fault. Engine power will be reduced after a certain time defined by an authority.

Solution

First save the error log and then erase it. Restart the ECU after erasing the error log. If the fault occurs again during the next driving cycle, check the following paths:

  • Check the DEF supply module wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check the operation with another DEF supply module to see if the supply module is defective.
  • Check the ECU operation with another EEM4 controller. If the system is functional and the fault is not active with the replacement ECU, then the original ECU is defective.