Detroit DD15 GHG14 (2014-16) Fault Code: SPN 158 FMI 2 (MCM, CPC ) Ignition Switch Not Plausible

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

NOTE: If inactive, clear the code, cycle the engine, and see if comes back. If it doesn’t problem solved.

Otherwise, possible failures are:
1. Measure voltage on the ECM 21-pin connector pin 7 and ground. If less than 11.5 V, repair the wiring to pin 7.
2. If 11.5V or greated, find the Common Powertrain Controller connect #2. Measure the voltage between pin 3 and ground. If less than 11.5V, find source of problem.