2.2.371. SPN 5491, FMI 4, DEF heater relay: Heater short circuit to ground.ΒΆ

Description

The EEM4 monitoring system has detected a short circuit on the DEF heater relay control circuit.

Possible causes are:

  • The DEF heater relay wiring is defective. (Shorted to ground.)
  • The DEF heater relay is defective

Reaction in EEM

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

Solution

First save the error log and then do the procedure that follows:

  • Examine the DEF heater relay wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Try the operation with another DEF heater relay to see if the relay is defective.