Detroit DD15 GHG14 (2014-16) Fault Code: SPN 520326 FMI 3 (ACM) Under Pressurized Diesel Exhaust Fluid System

Description

DESCRIPTION:
This diagnostic is typically an under pressurized diesel exhaust fluid (DEF) system.

MONITORED PARAMETER:
DEF pump speed vs. DEF pressure.

TYPICAL ENABLING CONDITIONS:
DEF pump enalbed or on-off-cycle request.

EXECUTION FREQUENCY:
Continuous when enabling conditions met.

TYPICAL DURATION:
Continuous until resolved.

DASH LAMPS:
None

ENGINE REACTION:
None

VERIFICATION:
Parked regeneration/Selective catalyst reduction SCR ADS self-check routine.

NOTE: If any other codes are active, fix those first.

PROBABLE CAUSES:
1. Inspect the DEF dosing unit and DEF pump harness wiring & connectors.
2. Check all DEF lines for damage/blocks/kinks.
3. DEF pump suction filter.
4. DEF dosing unit inlet filter.
5. DEF tank header.
6. DEF tank supply filter.
7. Replace the pressure relief valve.