I have a 2003 F-150, 5.4 engine and I have recently replaced the PCM because it showed a no start code of U1262, But after replacement of the PCM, I still have the same issue. Hard Starting, Grinds three or for times then starts. I have read that the PCM can also cause a PCM relay failure, a Fuel Pump Relay Failure and actually cause a Scan Key Error and cause the Theft Light to flash. I have put it in the Ford Service Center but they seem bewildered on it also. Using my normal key it would grind a couple times then start and using my spare key it would grind a couple times, start and then Theft light flashes fast, then stops, then flashes slow. If I remember right the number of slow flashes indicates a certain code. Has any experienced anything similar? Thanks.

 

To me, the term "grind" isn't something that would be PCM or key related. What exactly do you mean by grind?

 

https://www.f150forum.com/f6/03-5-4l...-issue-527860/

 

when I turn key motor will try to start is what I mean by grind, old shade tree mechanic term where I come from. I try to start but will not turn over.. After 3 or 4 times will turn over. Ford said it threw a U1262 code that's why PCM change but still acts the same. Hard start.

 

Does it screech...as it would if the engine were running ?

 

doesn't screech. Just doesn't fire. First I was think fuel pump because it seemed like not getting fuel. It's like a truck from up north that hard starts in the winter because of cold. I just don't want keep trying to start it many times because might hurt starter or kill battery. When I twist key to start it will not fire on first. Second sometimes third or fourth try it will fire. i read that the check valve on fuel pump may be bad. But Ford. Says it's not throwing a code for that. I think some of these new mechanics depend to much on the code readers and not on suggestions of what to look at.

 

So your definition of grind = Crank or Turnover

Attempting to get on the same page here.

 

Grind is same as crank trying to turn over

 

The Theft light should never flash when the engine is running.

Your description of the "grinding" problem would be "crank-no start".

You should watch the PATS (Theft) light and report what it does. Key out it should flash slowly. Key in and turned to On it should glow solid for about 2 seconds then go out. Then the engine should start when you "crank" it by turning the key to Start.

The old shade tree stuff doesn't really work anymore, even on a 2003.

 

No, crank and turn over mean the same thing...hence the confusion.

I'll attempt to make out what you're trying say again.