Detroit DD15 GHG14 (2014-16) Fault Code: SPN 520328 FMI 7 (ACM) Diesel Exhaust Fluid System has Been Over-Pressurized

Description

DESCRIPTION:
Diesel Exhaust Fluid (DEF) pressure relief valve stuck closed.

MONITORED PARAMETER:
DEF Pressure

TYPICAL ENABLING CONDITIONS:
When service routine is enabled and during in-use checks under non-dEF dosing conditions.

MONITOR SEQUENCE:
None

EXECUTION FREQUENCY:
Service tool and during in-use checks under non-DEF dosing conditions.

TYPICAL DURATION:
2 Seconds

DASH LAMPS:
None

ENGINE REACTION:
None

VERIFICATION:
SCR ADS self-check.

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.