2.2.107. SPN 3031, FMI 14, DEF tank maximum defrost time exceeded.ΒΆ

Description

The maximum defrost time of the selective catalytic reduction (SCR) system has been exceeded. The allowed defrost time comes from authority.

Possible causes are:

  • The coolant flow of the diesel exhaust fluid (DEF) tank heating valve is prevented.
  • The DEF tank sensor wiring is defective.
  • The DEF tank sensor is defective.
  • DEF supply module heater is defective
  • DEF hose heater is defective

Reaction in EEM

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

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

Solution

First save the error log and then obey the solutions that follow:

  • Examine the coolant circulation of the DEF tank heating valve; The hoses from the engine to the DEF tank heating valve and back.
  • Try the operation with another DEF tank heating valve to see if the DEF tank heating valve is defective.
  • Examine the DEF sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Make sure the supply module heater is operating normally. Supply module front cover should feel warm when heater is active. Measure heater resistance from the supply module connector to check possible open loop.
  • Examine the DEF hose heaters operation. Hose should feel warm when heater is active. Measure heater resistance to check possible open loop.
  • Examine DEF system heater relay control.

See Tank heating valve for reference. See Supply module for reference. See SCR line heaters for reference.

NOTE: The DEF tank temperature and level sensors have a common reference GND.

  • Try the operation with another DEF tank sensor to see if the DEF tank sensor is defective.