Alarm Controls SPN5491 FMI: 3 Aftertreatment Diesel Exhaust Fluid Line Heater Relay - Voltage Above Normal or Shorted to High Source

Alarm Controls SPN5491 EXP BUTTON ENGRAVED PANIC

Circuit Explanation:
The power source for line heaters 1, 2, and 3 is provided by the aftertreatment diesel exhaust fluid line heater relay. The aftertreatment diesel exhaust fluid controller is in charge of controlling it.

Location of Component:
The original equipment manufacturer (OEM) determines the location of the aftertreatment diesel exhaust fluid line heating relay. For more details, consult the OEM service manual.

Requirements to Run the Diagnostics:
When the keyswitch is turned to the ON position, this diagnostic runs constantly.

Fault code setting requirements:
The diesel exhaust fluid controller for treatment notices that the voltage in the relay circuit for the diesel exhaust fluid line heater is higher than acceptable.

When the Fault Code Is Active, What Happens?
When the diagnostic runs and fails, the electronic control module (ECM) turns on the MIL and/or the amber CHECK ENGINE bulb.
If the engine is run for an extended amount of time when this issue is present, engine torque will be reduced.

Conditions for Clearing the Fault Code - Start the engine, run a key cycle, and let it idle for one minute to verify the repair.
-After the diagnostic runs and passes, the fault code status shown by the INSITE electronic service tool will change to INACTIVE.
-After the diagnostic runs and passes, the ECM will immediately turn off the amber CHECK ENGINE lamp.
After three consecutive trips during which the diagnostic runs and passes for OBD engines, the ECM will turn off the MIL.
-
To erase both active and inactive faults as well as extinguish the MIL for OBD applications, use the "Reset All Faults" command in the INSITE electronic service tool.

Potential Causes
-Short to battery voltage in the relay circuit for the heater of the diesel exhaust fluid line.
-Short in the diesel exhaust fluid controller harness to battery voltage.
-A defective diesel exhaust fluid controller aftertreatment.

UPC: 604840454919
Also known as: AC-SPN5491



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