Cummins ISX CM870 (2003-06) Fault Code: 259 PID: S017 SPN: 632 FMI: 7/7 The ECM detected that the fuel shutoff valve is stuck open mechanically or leaking.

Upon turning the keyswitch off, the ECM turns off the voltage supplied to keep the fuel shutoff open. The ECM continues to fire the fueling and timing actuators as the engine spins down. The ECM monitors fuel pressure using the fuel pressure sensor during this time. If the fuel pressure does not drop after the fuel shutoff valve is turned off, the ECM activates this fault.

Possible repairs:

1)Replace the fuel pressure sensor.
2)Replace the damaged fuel shutoff valve component.