3.2.215. SPN 4342, FMI 3, DEF backflow line heater control circuit short circuit to high SOURCEΒΆ

Description

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

Possible causes are:

  • The DEF backflow line heater wiring is defective. (Shorted to high source.)
  • The DEF backflow line heater 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 which is 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 backflow line heater wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check the operation with another heater to see if the heater is defective.