1998 Expedition Died
As we were towing it home, they said there was a beeping coming from behind the glove box, which is where the PCM is I think.
Kinda stuck on wether it could be PCM or fuel pump.
Would greatly appreciate any guidance.
If the PCM powered up, gain access to the inertia switch. Connect a test light or meter to the fuel pump power circuit, and see if it goes HOT during the pump priming cycle, ~2 seconds long at power-on. You need to determine which half of the truck to focus on.
The PCM doesn't have a beeper. The only things that should have that capability would be the GEM and airbag diagnostic module. The airbag diagnostic module is behind the glovebox.
I'd bet any wierd noises you're hearing are caused by low voltage from trying to start the engine. electronics don't like low voltage.
I don't think any Ford is known for just crapping out because the ECM just suddenly dies
I'd be more inclined to think fuel pump.
as they do go bad frequently.
I'd troubleshoot to that end.
If the PCM powered up, gain access to the inertia switch. Connect a test light or meter to the fuel pump power circuit, and see if it goes HOT during the pump priming cycle, ~2 seconds long at power-on. You need to determine which half of the truck to focus on.
The PCM doesn't have a beeper. The only things that should have that capability would be the GEM and airbag diagnostic module. The airbag diagnostic module is behind the glovebox.
When we turn the key on, check engine light does come on. Have not checked the inertia switch yet. He went ahead and bought a new fuel pump. When we dropped the tank, the filter on the fuel pump was coming apart, the mesh had separated. I'm "assuming" that some of the internal stuff from the filter made its was into the pump.
Battery was too dead to crank for more than about 5 seconds and my jump box was dead. Have it charging and will check it tomorrow. It's 1:50 am and I have to be up at 4:30 to go to work. Hopefully it starts in the morning. I will post an update as soon as I have one.
Thanks for the assistance.
Never got around to checking the fuel pump relay, or the inertia switch.
Im thinking it could be the relay on its last leg. I can't imagine the inertia switch causing this intermittent problem.











