Cummins ISX12 CM2250 (2010-12) Fault Code: 6259 PID: SPN: 1075 FMI: 4 Electric Lift Pump for Engine Fuel Supply- Voltage Below Normal or Shorted to Low Source

Circuit Description
The fuel lift pump circuit is a discrete output in the engine control module (ECM) that controls the electric fuel lift pump. The lift pump is grounded in the ECM.

Component Location
The fuel lift pump is mounted on the intake side of the engine.

Conditions for Running the Diagnostics
This diagnostic runs when the keyswitch is initially turned to the ON position.

Conditions for Setting the Fault Codes
The ECM detected the fuel lift pump signal circuit was detected to be greater than 0-VDC when the signal was turned ON by the ECM.

Action Taken When the Fault Code is Active
The ECM logs the fault code immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, and leave the key in the ON position 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
Possible causes of this fault code include:

An open circuit in the engine harness
A short circuit to battery in the engine harness
A malfunctioning fuel lift pump.

Possible Cause:
1) Electric Fuel Lift Pump failure
2) Engine harness
3) ECM calibration