Cummins ISX12 CM2250 (2010-12) Fault Code: 6261 PID: SPN: 677 FMI: 3 Engine Starter Motor Relay 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 original equipment manufacturer (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 equipment manufacturer service information for component location.

Conditions for Running the Diagnostics
This diagnostic runs when the keyswitch is in the ON position and when the 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 ECM detected the starter lockout relay PWM signal was not at system voltage when the PWM signal was commanded ON.

Action Taken When the Fault Code is Active
The ECM logs the fault code 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 Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the malfunction indicator lamp for on-board diagnostics applications.

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. This fault code can be caused by:

Open circuit in the starter lockout relay, OEM harness, or connectors
Short circuit to a voltage source in the OEM harness or relay.
This fault can also be set active if the over crank protection feature (starter lockout) is enabled, but the engine/ECM is not wired to support it.

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 calibration