4.2.258. SPN 521002, FMI 5, DEF pump direction valve high side current below normal or open circuitΒΆ

Description

The measured DEF pump direction valve high side current is below normal or open circuit.

Possible causes are:

  • The DEF supply module wiring is defective. (Shorted to ground.)
  • 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). Measure cable from DEF pump conncetor to Engine ECU to detec faulty cable.
  • Check the operation with another DEF supply module to see if the supply module is defective.