Cummins ISB4.5 CM2150 Fault Code: 584 PID: SID 39 SPN: 677 FMI: 3 Starter Relay Driver Circuit – Voltage Above Normal or Shorted to High 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 could be wired back to the ECM on some vehicles, or wired to chassis or block ground on others. Refer to 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 exact location.

Conditions for Running the Diagnostics
This diagnostic runs when the keyswitch is in the ON position and when the PWM device is being energized or de-energized. In some cases the diagnostic could also run at some fixed intervals.

Conditions for Setting the Fault Codes
The starter lockout relay circuit PWM signal is not detected to be system voltage when the PWM signal is turned on.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
-The Starter Lockout feature will be disabled.

Conditions for Clearing the Fault Code
-To validate the repair, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE light and the fault code will go inactive immediately after the diagnostic runs and passes.
-This fault code can also be cleared with INSITE™ electronic service tool.

Shop Talk
The ECM monitors the voltage level on this circuit. If it detects a voltage when the signal is commanded off, it records this fault code.

Possible Causes
-Open circuit in the starter lockout relay, OEM harness, or connectors
-Short circuit to a voltage source in the OEM harness or relay.