Detroit DD13 EPA10 (2010-13) Fault Code: SPN 973 FMI 13 (CPC) Engine Retarder Selection Signal is Missing

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

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

NOTE: If ECM has been programmed recently, check programming to ensure it is correct.

NOTE: This code is coming from another computer on the vehicle (ABS, Transmission, etc…).