PACCAR PX-9 CM2350 (2013-17) Fault Code:3559 PID: SPN:3361 FMI:4 Aftertreatment 1 Diesel Exhaust Fluid Dosing Unit – Voltage Below Normal or Shorted to Low Source

Reason:
Aftertreatment Diesel Exhaust Fluid Dosing Unit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the aftertreatment diesel exhaust fluid dosing unit.

Effect:
Possible reduced engine performance.

Circuit Description:
The aftertreatment diesel exhaust fluid dosing unit performs many functions, one of which is to generate adequate diesel exhaust fluid pressure in the lines, using a pump, to allow for dosing. The ECM provides a battery voltage supply and a ground to the diesel exhaust fluid dosing unit. The ECM also supplies a signal to the dosing unit to control the diesel exhaust fluid output. This signal changes, based on the diesel exhaust fluid pressure being commanded.

Component Location:
The aftertreatment diesel exhaust fluid dosing unit location is original equipment manufacturer (OEM) dependent. Refer to the OEM service manual.

Conditions for Running the Diagnostics:
This diagnostic runs when the diesel exhaust fluid dosing unit is in the priming or dosing state.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid dosing unit signal voltage or the aftertreatment diesel exhaust fluid dosing unit supply voltage was out of range low.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) Diesel exhaust fluid injection into the aftertreatment system is disabled.
3) 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 the “Aftertreatment Diesel Exhaust Fluid System Leak Test” found under “ECM Diagnostic Tests” in the INSITE™ electronic service tool
2) The fault code status displayed by INSITE™ electronic service tool 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 INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
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 Causes:
1) Short to ground in the diesel exhaust fluid dosing unit
2) A short circuit to ground in the OEM harness