Lamp:Amber

Reason:High aftertreatment diesel exhaust fluid flow detected.

Effect:Possible reduced engine performance.

Circuit Description:The aftertreatment diesel exhaust fluid dosing valve is controlled by the ECM. When the Engine Control Module (ECM) commands DEF dosing, the ECM sends a Pulse-Width Modulated (PWM) signal to the dosing valve, which opens the dosing valve and allows DEF to be sprayed into the exhaust stream.

Component Location:1. The aftertreatment diesel exhaust fluid dosing unit location is Original Equipment Manufacturer (OEM) dependent.2. The aftertreatment diesel exhaust fluid dosing valve is installed in the exhaust system. It is mounted directly to the aftertreatment decomposition tube, before the Selective Catalytic Reduction (SCR) catalyst. Installation position will vary, based on the aftertreatment architecture and the Original Equipment Manufacturer (OEM).

Conditions for Running the Diagnostics:This diagnostic runs when the diesel exhaust fluid dosing valve is being commanded on.

Conditions for Setting the Fault Code:The Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid dosing performance is high.

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, perform the “aftertreatment diesel exhaust fluid doser pump override test” found under “ECM diagnostic tests” in the recommended diagnostic tool or equivalent.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. 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.5. 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 dosing unit.2. A malfunctioning aftertreatment diesel exhaust fluid dosing valve.