Cummins ISB6.7 CM2350 (2013-17) Fault Code: 1679-Multiplexed PID: SPN: 3031 FMI: 2 Aftertreatment 1 Diesel Exhaust Fluid Tank Temperature- Data Erratic, Intermittent, or Incorrect

Cummins ISB6.7 CM2350 (2013-17) Fault Code: 1679-Multiplexed PID: SPN: 3031 FMI: 2 Aftertreatment 1 Diesel Exhaust Fluid Tank Temperature- Data Erratic, Intermittent, or Incorrect

Circuit Description
The aftertreatment diesel exhaust fluid tank temperature sensor is used to monitor the temperature of the aftertreatment diesel exhaust fluid inside the aftertreatment diesel exhaust fluid tank.

Component Location
The aftertreatment diesel exhaust fluid tank temperature sensor is part of the dosing unit which is located in the DEF tank

Conditions for Running the Diagnostics
The engine must be turned OFF for period of 8 hours before this diagnostic will run. This diagnostic runs when the keyswitch is turned to the ON position after an 8 hour cold soak.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid tank temperature sensor reading was higher or lower than the other temperature sensors on the engine.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault Code
1)To validate the repair, the engine must be shut down with the keyswitch in the OFF position for 8 hours. 2)After the 8 hour cold soak, start the engine and let it idle for 1 minute.
3)The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
4)The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
5)For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
6)The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Possible causes:
1) In-range failure of the diesel exhaust fluid tank temperature sensor
2) Damaged wiring harness

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

If there is a Low Coolant fault active or very recently inactive, please ensure low coolant is adequately resolved and all air is out of the system before troubleshooting

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.