Detroit DD15 GHG14 (2014-16) Fault Code: SPN 84 FMI 7 (CPC) Vehicle Speed Signal Hall Effect VSS Wiring Mismatch, Rationality Fault

NOTE: Please see the step by step troubleshooting procedures for this specific code.

NOTE: If codes are present relating anything to battery or voltages, repair those first.

PROBABLE CAUSES:
1. CPC (Engine ECM) has been improperly programmed or configured.
2. The source problem is other computers (Transmission, ABS, Cab, etc…) on the truck.