XJL Intermittent Starting Problem

[Mitchell G]

Hi, My 2015 XJL has developed an intermittent problem of on occasions it will not turnover and start. This appears to be linked with opening and closing the boot as the non-starting can occur after I have placed something in the boot and sometimes can start after opening and shutting the boot.  Recently the engine stopped when in traffic I pulled into the side of the road to allow oncoming traffic through…..the ECO stop start stopped the engine and it refused to restart. I opened the boot using the switch on the dash, got out of the car and closed the boot, got back into the car and it started. The battery is new and has been coded into the car. I have had the boot latch and starting motor replaced and the problem exists. Earthing appears to be OK. My local Jaguar dealer can not find the issue and neither can local auto electricians ?  I am at my wits end !!!  Have any of you guys come across this issue and advise me how it was resolved.

 

[LairdScooby]

I have a similar thing on my 99 S Type, if i open the boot before arming the alarm, often it will not arm/set. If i open and close one of the doors (drivers door usually) i can then set the alarm. I've put this down to perhaps a worn door open switch on the drivers door or possibly whichever module (BCM perhaps) not recognising all doors are shut. It sounds to me as if you have a similar problem brewing but in a later stage.

Also worth checking to see if it does it with your spare key, if it doesn't, get yourself a replacement spare and start using the spare key.

[Mitchell G]

Hi

Thanks for your response. I have had the same issue with either of my keys and I have replaced the batteries in both. I had a new drivers door latch fitted as well as tgd new boot latch. One garage told me it was the gear selector unit, so that was replaced and the problem still exists. It is with an auto electrician at the moment but it starts every time he tries, so no fault appears on the diagnostic……. Soul destroying !

[LairdScooby]

Having worked most of my life in electrical/electronic engineering, I can confirm there is nothing more frustrating than having to write on the job sheet "NFFAT" - No Fault Found At Test.

Over the decades ive had many "Intermittently Intermittent" faults as i call them. Sometimes it's has been a long and extremely annoying process to find the fault and often when i do, i find it's a "Compound Intermittent Fault" - one where two or more problems contribute to not only the intermittent fault but the overall intermittency of it occurring in the first place.

I wish you and your autoelectrician luck with finding it, you may have to lose this battle to win the war and come to an arrangement with him whereby he comes to you when it faults to investigate. This isn't just a "Jag thing", it happens to all makes and some are much worse than others! 'Tis the nature of the beast with electrical/electronic systems sadly.