Cummins ISB4.5 CM2150 Fault Code: 1683 PID: 202C SPN: 3363 FMI: 3 Aftertreatment Diesel Exhaust Fluid Tank Heater – Voltage Above Normal or Shorted to High Source.

Circuit Description
The aftertreatment diesel exhaust fluid tank heater keeps the diesel exhaust fluid from freezing in the diesel exhaust fluid tank. The heating element is powered by the diesel exhaust fluid tank heater relay.

Component Location
The diesel exhaust fluid tank heater is located in the diesel exhaust fluid tank. The location of the diesel exhaust fluid tank heater relays will vary by OEM. Refer to the OEM service manual for more information.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes
Circuit error between the ECM and the diesel exhaust fluid tank heater relay has been detected.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light and/or the MIL immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code
-To validate the repair, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.
-The ECM will turn off the MIL after 3 consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Shop Talk
This fault code can not detect any circuit failures on the heater side of the relay. Only circuit errors between the ECM and the relay can be detected by this fault code.

Possible Causes
-Diesel exhaust fluid tank heater relay signal wire not connected to the relay
-Diesel exhaust fluid tank heater relay return wire not connected to the relay
-Malfunctioning diesel exhaust fluid tank heater relay
-Open circuit in the diesel exhaust fluid tank heater relay signal wire
-Open circuit in the diesel exhaust fluid tank heater relay return wire
-Diesel exhaust fluid tank heater signal wire shorted to a voltage source.