Make: Detroit
Engine: DD15 GHG17 (2017 & Newer)
PID: N/A
SPN: 520321
FMI: 31

Description: Internal MCM Error
Troubleshooting:
DESCRIPTION:
Internal MCM error detected.
MONITORED PARAMETER:
MCM
TYPICAL ENABLING CONDITIONS:
Always enabled
MONITOR SEQUENCE:
None
EXECUTION FREQUENCEY:
Always enabled
TYPCIAL DURATION:
Two seconds
DASH LAMPS:
CEL
ENGINE REACTION:
None
VERFICATION:
Key on
POSSIBLE CAUSES:
1. MCM needs reprogramming.
2. Faulty MCM.

Make: Detroit
Engine: DD15 GHG17 (2017 & Newer)
PID: N/A
SPN: 520321
FMI: 31

Description: No Match of Camshaft and Crankshaft Signals – engine cold
Troubleshooting:
DESCRIPTION:
This fault code sets when the Camshaft signal is 6 degrees different from the crankshaft signal
for 50 counts.
MONITORED PARAMETER:
Camshaft/Crankshaft sensors.
TYPICAL ENABLING CONDITIONS:
1. Engine idle.
2. Engine coolant temperature less than (87°C)188 °F.
MONITOR SEQUENCE:
None
EXECUTION FREQUENCEY:
Continuous when enabling conditions met.
TYPCIAL DURATION:
10 seconds
DASH LAMPS:
1. MIL
2. CEL
ENGINE REACTION:
None
VERFICATION:
Engine idle (1 minute).
POSSIBLE CAUSES:
1. Faulty camshaft timing.
2. Faulty camshaft position sensor connector.
3. Faulty camshaft position sensor.

Make: Detroit
Engine: DD15 GHG17 (2017 & Newer)
PID: N/A
SPN: 520323
FMI: 3

Description: High Side Digital Output Supply Voltage Circuit Failed High
Troubleshooting:
DESCRIPTION:
High side digital output supply voltage circuit failed high.
MONITORED PARAMETER:
DEF dosing unit voltage.
TYPICAL ENABLING CONDITIONS:
DEF dosing enabled.
MONITOR SEQUENCE:
None
EXECUTION FREQUENCEY:
Continuous when enabling conditions met.
TYPCIAL DURATION:
5 seconds
DASH LAMPS:
1. MIL
2. CEL
ENGINE REACTION:
Derate 25%
VERFICATION:
Parked regen
POSSIBLE CAUSES:
1. Bent pins
2. Spread pins
3. Corroded pins
4. Faulty wiring

Make: Detroit
Engine: DD15 GHG17 (2017 & Newer)
PID: N/A
SPN: 520323
FMI: 4

Description: High Side Digital Output Supply Voltage Circuit Failed Low
Troubleshooting:
DESCRIPTION:
High side digital output supply voltage circuit failed low.
MONITORED PARAMETER:
DEF dosing unit voltage.
TYPICAL ENABLING CONDITIONS:
DEF dosing enabled.
MONITOR SEQUENCE:
None
EXECUTION FREQUENCEY:
Continuous when enabling conditions met.
TYPCIAL DURATION:
5 seconds
DASH LAMPS:
1. MIL
2. CEL
ENGINE REACTION:
Derate 25%
VERFICATION:
Parked regen
POSSIBLE CAUSES:
1. Bent pins
2. Spread pins
3. Corroded pins
4. Faulty wiring

Make: Detroit
Engine: DD15 GHG17 (2017 & Newer)
PID: N/A
SPN: 520328
FMI: 7

Description: Diesel Exhaust Fluid System has Been Over-pressurized
Troubleshooting:
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 FREQUENCEY:
Service tool and during in-use checks under non-DEF dosing conditions.
TYPCIAL DURATION:
2 seconds
DASH LAMPS:
None
ENGINE REACTION:
None
VERFICATION:
SCR ADS self-check.
POSSIBLE CAUSES:
Faulty Pressure Relief Valve (PRV).