Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 585 PID: SID 39 SPN: 677 FMI: 4 Starter Relay Driver Circuit- Voltage Below Normal or Shorted to Low Source

Circuit Description
The starter lockout relay is controlled by the engine control module (ECM) through the starter lockout relay signal circuit. The relay prevents the starter from being engaged when the engine is running. The relay return circuit is dependent on OEM wiring. It can be wired back to the ECM on some vehicles or wired to chassis or block ground on others. Consult the OEM wiring diagram for return circuit details. The starter lockout relay circuit utilizes a pulse width modulated (PWM) signal. A PWM signal is a pulsed voltage signal between 0-VDC and system voltage. The frequency of the pulsed voltage signal is dependent on the application requirement.

Component Location
The starter lockout relay is installed by the vehicle OEM. Refer to the OEM service manual for component location.

Conditions for Running the Diagnostics
This diagnostic runs when the keyswitch is in the ON position and when the pulse width modulated (PWM) device is getting energized or de-energized. In some cases, the diagnostics can also run at some fixed intervals.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the starter lockout relay pulse width modulated (PWM) signal was at system voltage when the pulse width modulated (PWM) signal was commanded OFF.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
The Starter Lockout feature will be disabled.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk
The ECM monitors the voltage level on this circuit. If it detects a low voltage when the signal is commanded ON, it records this fault code. This fault code can be caused by a short circuit to ground in the starter lockout relay, OEM harness, or connectors.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

Possible Cause:
1) Starter Lockout relay failure
2) OEM harness
3) ECM failure