Detroit DD13 EPA07 (2007-09) Fault Code: SPN 904 FMI 13 (CPC) Front Axle Speed Signal is Missing

NOTE: Front axle speed signal is missing.

NOTE: If codes 168-0, 168-14, or 168-18 active fix those first.

PROBABLE CAUSE:
1. CPC has improper programming.
2. There is another computer on the vehicle (ABS, Transmission, Cab, etc…) that is causing the problems.