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2006 GMC Yukon - Won't start

I’ve got another of what seems to be a great mystery of the internet… I’ve seen several people posting similar experiences and never any definitive cause or solution. It’s an 06 Yukon Denali, 250k miles. Every now and then, I’ll get in the car and turn the key, lights and dash all come on nice and strong, turn the ignition, nothing.

It seems to happen pretty consistently after I stop for gas on a long drive, after at least an hour of driving (but not always), and it’ll sometimes happen after it’s been sitting in an open parking lot all morning in the summer here in Mississippi.

The fuel pressure was low, so we’ve replaced the fuel pump. The starter, battery and alternator are all good. (When it does crank it cranks up nice and strong, no problem).

When it happens, I’ll try it a few more times, and it might work on the 3rd or 4th try. Sometimes I’ll keep the key turned, put it in neutral and try it and sometimes that’ll work. Sometimes it’ll start after 15 minutes, sometimes 2 hours.

Recently, I found a bandaid that has worked pretty reliably… if I pull a 10a fuse in the box under the hood labeled “crank,” wait 10 seconds and plug it back in, it’ll start.

I’ve seen some people suggest it’s some wires connected to the anti-theft system starting to go out, trigger a no start. So I guess the next thing I’ll try is replacing whatever wiring I can figure out how to replace. But I figured I’d put this out wherever I can find a place to put it to see if anyone knows for sure what this is about.

Have you considered that the fuel pump relay or start relay have worn out?

Sure haven’t. That an easy thing to check?

The next time this happens, with the dash lights on, step on the brake pedal and shift the transmission into neutral and then try starting the engine.

If the engine starts, it points to a problem with the park/neutral safety switch.

Tester

Yeah I usually try that, it works maybe 10% of the time. But I’ll put that on the list of things to check!

Very easy to check. They reside in the fuse box underhood. They should be marked on the inside of the lid. They just unplug by hand, no tools needed. Just replace them, they are 13 years old and have cycled a ton over 250k miles.