Cummins ISX12 CM2250 (2010-12) Fault Code: 1673 PID: SPN: 1761 FMI: 1 Aftertreatment Diesel exhaust Fluid Tank Level- Data Valid But Below Normal Operating Range- Most Severe Level

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

Component Location
The diesel exhaust fluid level sensor is located in the diesel exhaust fluid tank. Location of the tank and level sensor is OEM dependent. Refer to the OEM service manual.

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

Conditions for Setting the Fault Codes
The diesel exhaust fluid tank is critically low.

Action Taken When the Fault Code is Active
There are three levels of action taken by the ECM when this fault code is active:

Level 1: Action taken immediately after the diagnostic runs and fails.

The ECM illuminates the amber CHECK ENGINE light and/or the Malfunction Indicator Lamp (MIL).
The diesel exhaust fluid lamp will be flashing.
Engine torque will be reduced.
Level 2: Action taken when the diesel exhaust fluid tank is empty:

The ECM illuminates the amber CHECK ENGINE light and/or the Malfunction Indicator Lamp (MIL).
The diesel exhaust fluid lamp will be flashing.
Engine torque will be severely reduced.
Level 3: Action taken when the diesel exhaust fluid tank is empty and with engine shutdown or extended idle:

The ECM illuminates the amber CHECK ENGINE light and/or the Malfunction Indicator Lamp (MIL).
The diesel exhaust fluid lamp will be flashing.
Engine torque will be severely reduced.
Vehicle speed will be limited to 8 km [5 mi] per hour.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
This fault code indicates that the Diesel Exhaust Fluid (DEF) level is critically low and there will be a power loss. Engine power will be reduced automatically. This can be corrected by refilling the DEF tank. Normal engine power will be restored after refilling the DEF tank.

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

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.

Possible Cause:
1) ECM calibration