2004 Yukon No start. Security ???

Buddy at work has a Yukon that sometimes won't start. He tells me it's very random. Hot,Cold,Day,Night.. Just when ever it decides not to start..It wont.

I'm thinking fuel pump cut off or Fuel pump relay....

Then he tells me his neighbor know a person with the same problem. Neighbor says to roll the truck halfway out the driveway ( Incline ) and try to start it there.

It works.

This just puzzled me... WTF does a slight incline have to do with anything ? Gas tank is never empty enough for it to be that.

Then today he tells me he had a co-worker pick up his truck by the tow hooks with a hi-lo. Truck starts..

As he leaves today , same thing.. Hi-lo-Truck-Start.

He asked me to turn the key, That's when the eureka moment happened.

I believe his version of PATS known as Passkey or Passlock is messing this up.

IIRC most security measure disarm when the vehicle is raised so many degrees as when being towed.



So here is why I am rambling to you guys...

Do these types of systems have a mercury switch somewhere ?

Can I move it's orientation somehow and save him a HUGE dealer bill on the fix ?

Do ya think the Passlock reprogram steps ( So many on and off with key and such ) will help as the problem is random ?

Do you guys have any other suggestions ?

I'm quessing the key switch is in the on position the whole time he is getting the truck lifted to start it. If so check fuel pressure.