Detroit DD13 EPA07 (2007-09) Fault Code: SPN 679 FMI 7 (MCM) Pressure Limiting Valve (PLV) Staying Open
NOTE: The pressure limiting valve will open when rail pressure is above 1150 bar. The motor control module (MCM) will command a lower rail pressure trying to force the pressure limiting valve closed. If the pressure limiting valve does not close, a fault code is generated. The condition that caused the PLV to open must be addressed.
DESCRIPTION:1. Pressure limiting valve.2. Failed to close.
MONITORED PARAMETER:Pressure limiting valve.
TYPICAL ENABLING CONDITIONS:10 seconds
MONITOR SEQUENCE:None
EXECUTION FREQUENCY:Continuous when enabling conditions met.
TYPICAL DURATION:10 seconds
DASH LAMPS:1. MIL2. CEL
ENGINE REACTION:Derate 25%
VERIFICATION:Engine Idle: One minute.
NOTE: The PLV will open with rail pressure is above 1150 bar.
PROBABLE CAUSES:1. If any other codes present, fix those first.2. If at idle you have above 900 bar, check for damaged needle return line and a damaged line (fuel rail to fuel injector).3. If at 1800 rpm you have above 900 bar, check for damaged needle return line, damaged amplifier return line, and a damaged line (fuel rail to fuel injector).4. If fuel pressure stays below 900 bar, replace the PLV.