Fuel Shut Off Solenoid fits 1994 - 2001 Chevy GMC 6.5L with Electronic DS4 Pump. Part # AP63548 - Stanadyne Part# 33072 (Discontinued)
The fuel shutoff solenoid for DS4 injection pumps is prone to leaking or failing altogether and causing a no-start situation. If the shutoff solenoid fails, then 1994-1995 trucks should see a DTC #13 (Engine ShutOff Solenoid Circuit Fault), and 1996-up might see DTC #P0215 (Engine ShutOff Control Circuit). A simple test can also be conducted to determine if the solenoid has failed. Simply unplug the solenoid electrical connector and use an ohm meter to check for continuity between the 2 terminals. Zero continuity will indicate that the solenoid is bad. You can also remove the solenoid from the pump and energize the terminals with a 12 volt power source to see if the solenoid plunger pulls in.
Removal of early style solenoids that require a hex bit can be tricky because the solenoid can be fairly tight and the hex bit may slip and round out the hole. We've found that gently tapping squarely on top of the solenoid with a small hammer will loosen the solenoid enough to remove it without rounding out the hex hole.
