Hi All

Looking for some help with my 2015 V8R AWD.
I have an intermittent fault that only appears to happen when the ambient temperature is warm/hot and the car has been out on a run.
It won't start again until everything has cooled down!
From cold it starts on the button. Battery checked and is fine.
This only happens when it's hot.
Press the brake pedal (no warning shown), press start/stop, all the dash lights come on as expected, needles do their thing but no crank.
I'm suspecting one of the following; starter motor (it's done 75,000), earth point or relay.
I'd rather start with the cheaper (and easier) options but cannot find anywhere that tells me where the relay is or a diagram of the various earth points.
Any help would be appreciated. Thank you.

 

The workshop manual should have the diagram that you are trying to find. A link to it is in the thread below. Beware though the manual is over 6,000 pages. The manual is for the V6 but should be substantially similar to the V8 version.

https://www.jaguarforums.com/forum/f...manual-196553/

 

Thank you.
There's some reading for me!

 

It could also be a switch or sensor. These pushbutton start systems aren't like the old days. It used to be that when you engaged the start position it would directly activate the starter relay, give or take a few safety switches. Now, the starter button is just another input to the computer, and if it decides to honor the request to start, it will activate the relay. It might be the neutral safety switch, so you could try starting in neutral instead of park. Not sure how that part works and haven't investigated, given my 6MT.

In any case, diagnosing these kinds of things can be a pain. You may have some clues in stored codes but again, I'm speculating. Good luck!

 

You have the right idea. Check grounds under the car at transmission bell housing and inside the front wheel well (which side varies). Also check the ground from the starter itself. Lastly, has your battery been changed recently?

 

Had the same exact problem with my 2015 V8R RWD. Only happens after engine was hot; when I waited for it to cool down (usually 1-2 hours), it would start again.

See video:
I showed that video to a local indy, and he fixed it in an hour. He said:

“There was a loose ground strap between engine and chassis that needed tightening.”

Hope your fix is as simple too!

 

Thanks for your reply.
Looks like an exact match of symptoms.
I'll get under it next week, take a look and let you know.