Detroit DD16 GHG14 (2014-16) Fault Code: SPN 677 FMI 2 (MCM) Starter Switch Inconsistent

DESCRIPTION:
This fault code sets when the Motor Control Module (MCM) sees that the starter ignition status from the Common Powertrain Controller (CPC) and MCM do not match.

MONITORED PARAMETER:
Starter Voltage Signal

TYPICAL ENABLING CONDITIONS:
Engine Start

MONITOR SEQUENCE:
None

EXECUTION FREQUENCY:
Always Enabled

TYPICAL DURATION:
2 Seconds

DASH LAMPS:
CEL

ENGINE REACTION:
None

VERIFICATION:
Engine Start

PROBABLE CAUSES:
1. If 677-2 inactive, clear the code, start the engine, and if it doesn’t come back release the vehicle.
2. Wiring on the MCM 21-pin connector between pin 20 and ground. Should have 11.5 or more volts.
3. Wiring on the CPC connector #1 between pin 18 and ground. If less than 11.5 Volts, repair wiring.