I have a 2004 F150 FX4 and the engine light recently came up, so I had it scanned and the code P1233 means that the Fuel Pump Module Off Line. The last time the engine light came on it was related to the fuel pump intertia switch. The truck runs fine, but I need to get the problem fixed if there is one. Does any one have any idea on where to start with this? I'm guessing it is a sensor or module replacement issue, but do not know.

 

This could be tough. Sounds like you are dealing with a intermitent problem.
was P1233 a hard code or was it a memory code?
It could be anything from the PCM, fuel pump relay, inertia switch, fuel pump driver module or the wiring and connectors between any of them.

 

Thanks ohboy44, but I found the problem. It was simply the fuel pump driver MODULE that went bad, so I should be set once that is replaced.

 

Make sure the wiring at the plug is good. The 2 wires that communicate with the PCM have very small terminals and the locks have been known to break.