Detroit DD13 EPA07 (2007-09) Fault Code: SPN 3661 FMI 14 (MCM) Injector Cylinder #3 Amplifier Control Valve Abnormal Operation

NOTE: If codes 168-xx or 723-xx active, fix those first.

PROBABLE CAUSES:
1. Inspect front fuel injector harness 14-pin connector.
2. Front injector harness failure.
3. Failed injector.
4. Engine side harness failure.
5. Failed MCM (Engine ECM).