ISX12/ISX11.9 CM2250 Fault Code: 3648 | SPN: 5480 | FMI: 16Aftertreatment Diesel Exhaust Fluid Controller Temperature – Data Valid But Above Normal Operating Range – Moderately Severe Level

Overview

Circuit Description

The aftertreatment diesel exhaust fluid controller is the central control for the selective catalytic reduction (SCR) diesel exhaust fluid dosing system, and handles the dosing activity, tank level sensing, tank temperature sensing, line heating, and tank heating. The diesel exhaust fluid controller communicates to the engine control module (ECM) via the J1939 data link connection.

Component Location

The aftertreatment diesel exhaust fluid controller in equipped with an internal temperature sensor, which monitors the temperature inside the controller during operation. This temperature sensor is internal to the diesel exhaust fluid controller and cannot be service separately.

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 Codes

The internal temperature of the diesel exhaust fluid controller was greater than 114°F [238°C] for more than 5 seconds.

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.
• Diesel exhaust fluid injection into the aftertreatment system is disabled.

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

• To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
• The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
• 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.
• The “Reset All Faults” command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk

Troubleshoot high inactive counts of Fault Code 3648 as an active fault code.

Possible causes of this fault code include:

Inadequate air flow to cool diesel exhaust fluid controller

Improper mounting of diesel exhaust fluid controller

Malfunctioning diesel exhaust fluid controller.

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.