ISX12/ISX11.9 CM2250 Fault Code: 3557 | SPN: 3360 | FMI: 2Aftertreatment Diesel Exhaust Fluid Controller – Data Erratic, Intermittent, or Incorrect

Overview

Circuit Description

The SCR dosing system is an In-tank system with a Dosing control unit (DCU) that controls the dosing pump and monitors Urea heating, level, quality, pressure and temperature. This Dosing system is powered by battery voltage and an initialization signal from the smart power relay. The (DCU) activates Priming, dosing, heating and purging of urea using data provided by the Engine Control module (ECM) via the J1939 datalink. The DCU performs its own diagnostics and reports malfunctions back to the ECM. The ECM then decodes the error and converts it to a fault code.

Component Location

The location of the aftertreatment diesel exhaust fluid controller varies by application and OEM. The controller will typically be mounted to the vehicle frame or suitable rigid bracket using three or four capscrews. Refer to the OEM service manual for a more detailed component location description.

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 operating conditions were too high or low on the sensor supply between the diesel exhaust fluid controller and the dosing unit.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
• 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

The aftertreatment diesel exhaust fluid controller is not serviceable, and must be replaced when manlfunctioning.

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.