Cummins X15 CM2350 X116B Performance Series (2018 & Newer) Fault Code: 4679 PID: SPN: 1761 FMI: 5/5 Aftertreatment 1 Diesel Exhaust Fluid Tank Level Sensor Circuit – Current Below Normal or Open Circuit

Lamp:
Amber

Reason:
Low current or an open circuit has been detected at the diesel exhaust fluid tank level sensor.

Effect:
Possible reduced engine performance.

Circuit Description:
The aftertreatment Diesel Exhaust Fluid (DEF) sensor is a smart device that communicates to the ECM via the J1939 datalink. The aftertreatment DEF sensor performs its own internal diagnostics and reports malfunctions back to the primary engine control module via the J1939 datalink. The aftertreatment DEF sensor monitors the tank level, temperature and quality of the DEF fluid. The aftertreatment diesel exhaust fluid tank level sensor is used to monitor the aftertreatment diesel exhaust fluid level inside the aftertreatment diesel exhaust fluid tank.

Component Location:
The aftertreatment diesel exhaust fluid tank level sensor is located in the aftertreatment diesel exhaust fluid tank. Location of the tank and level sensor is OEM dependent.

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

Conditions for Setting the Fault Code:
The aftertreatment DEF sensor detected an internal open circuit.

Action Taken When the Fault Code is Active:
1. The ECM illuminates the amber check engine lamp immediately when the diagnostic runs and fails.
2. Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1. To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2. The fault code status displayed by the recommended diagnostic tool or equivalent will change to inactive immediately after the diagnostic runs and passes.
3. The ECM will turn off the amber check engine lamp immediately after the diagnostic runs and passes.
4. The “reset all faults” command in the recommended diagnostic tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
Possible causes of this fault code include:
1. A malfunctioning aftertreatment diesel exhaust fluid tank level sensor.
2. Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
3. 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.