Has this happened to you? You get in your car, press the brake, press start and click! Lights but no action? This has been happening to me since new.

I have tried everything including new key fob batteries, jumping the car, holding the fob to the dash sensor, locking it, unlocking but never have figured out why it wouldn't start.

Here is what I found. If the car has been sitting for some duration (3+ days), when I get back in the car it won't start. To make it start this is what has worked for me every time:
1) Get in car, won't start. Must do this first.
2) Get out. Lock door. (Just lock + unlock from the inside doesn't work)
3) Unlock door
4) Get in and start. Works!

If I don't do that exact procedure, the security system always locks out the start but doing the whole nonsense of in-out-lock-unlock-in-start makes it happy. No battery or fob issues it turns out.

Anyone else? Hope this solves your problem if you have the same issue.

 

One of my XF's has similar symptoms, but it's just a matter of me pressing harder on the brake pedal.

Try that next time to see if you might have the same issue and you just happen to be pressing on the brakes harder making you think it's this voodoo procedure that's required.

 

This has happened to me a few times in my 4 years of ownership. Push harder on the brake...car starts.

 

Failure to start on first press of the starter button has happened to me I'd guess fewer than 10 times over the course of 4 years. A second press of the button has worked every time, no need to go through any of the sequence you describe.

 

This happened to me a few times, and yes, pressing the brake pedal harder is the answer. It is a sign that the brake pedal switch is on the way out. It is a cheap fix, around US$25. The Jaguar SDD seems to have a way to re-set the pedal pressure sensor in case you or the previous owner have/had a light or heavy foot.

 

When you try to start the car and it fails, does the brake pedal feel hard? Common issue if you hold down the brake pedal after turning off the ignition or pump it a couple of times as you get into the car - all the brake boost is lost (the power assist so to speak) and the pedal is v hard. So although the brake pedal switch is still working fine, you have to push the brake pedal really hard to trigger it as the pedal is so stiff

 

Hmmm...I will try the brake trick but it does not make sense since I press the same both times and it only works when I exit-lock-enter as I stated. That is more indicative of a software bug due to a timeout condition.
If I jump in the car day to day it never happens...more later.

 

That makes perfect since. "Day to day driving and it works fine, let it sit for a few days and it won't start."

If that is what you re saying?


Sounds to me you have a slow vacuum leak in the brake booster. Let sit for a few days and you loose your booster assistance, then the brake pedal has to be pushed harder to overcome the lack of assistance so the pedal is pressed far enough to trip the electrical circuit to allow the car's ECU to spin the motor over.

 

Again, it makes no sense since exiting-locking-and re-entering allows it to start with the same pressure on the pedal. Will try the forum's suggestion tho next time.

 

Well I guess I'll be an uncle's monkey...it appears you and the others who suggested this are right. I encountered the "no start" twice now after sitting 5-6 days each time and pushed harder on the brake pedal and sure enough it started! Gulp! I have been fighting this since new and just got schooled! Thanks everyone.

 

Glad you have it sorted!

 

Do you know what switch this is? and where its located. I would like to repalce it.

Also where in the SDD can you re-set the pedal pressure sensor?

Thank you for any help.

 

I had the same problem with my 2010 XF. See if this helps.

Link. JagRepair.com - Jaguar Repair Information Resource

Gus
JagRepair.com - Jaguar Repair Information Resource

 

• hi, i seem to have the same issue as what is being described here and would like to fix it also. What is the name of the switch please? Thanks in advance.

 

This is the switch I used. It was a lot of fun manipulating my body so I can get my hand in the right position to remove and replace.

From RockAuto; Alternate/OEM Part Number(s): 1S11062, 6E5Z13480A, 6W8313480AB, 6W8313980AB, 7E5T96854M, 7E5Z13480A, C2914525, C2P14525, SW8240, SW8280, XKB500030, XKB500110

 

 

So glad I found this thread! Thank you everybody!

Got this 2010 XF with 36k miles on it, new battery but would not start for me. Same procedure as my 2017 Subaru Outback so I was baffled. For months I had the XF on a trickle charger, dorking with it once in a while. Poked my finger thru the thin start button membrane. Never considered pushing harder on the brake pedal.

Shoulda looked for this place sooner!