So maybe every 3rd or 4th time I have an issue with starting. I know everyone is gonna say battery but I don’t think so. This is what happens, I unlock and open the door, everything seems fine, bright headlights on, mirrors deploy sounding lively. Inside the steering column goes to its rightful position, I press brake pedal the start button then absolutely nothing except a slight whirring noise. Feels like a completely dead battery so I try again same thing. I get out double lock the doors (by now I know it’s not a dead battery) double unlock the doors, get back in starts first time with a burst of life! Until the next time.

i do feel that it’s maybe happening more frequently now. Is it an earth issue or is there a known issue with the start button or brake pedal? I don’t think it’s something I could fix but any ideas would be appreciated.

 

A lot of folks are going to chime in and ask you to test the battery and you should. You can drive it to an auto parts store and they will load test and voltage test it for free. Consider checking the ground cable on the battery itself, ensuring it's very tight on the battery and then ground points.

Before diving into things like start switch and brake switch, personally, I eliminate the first and easiest test the battery. In your case, grounding issue would send me there.

 

Do the brake lights come on when pushing the brake pedal? You might try pushing harder on the brake as that has been reported too.
Another tip I have seen is to press the start button without touching the brake. Keep holding the button down and after the car comes alive now push on the brake and it should start immediately.
Just something to try.
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There is a ground strap for the engine that is known to give problems on some XK's - there was a youtube posted recently showing the braided strap almost shredded. It might be worth getting under the car and check the ground strap.

Edit - here's the video:

 

That looks to be a ground for the tranmission - the starter motor has a ground point on the motor itself - unfortunately the Jag has a multitude of ground points, I was a long time going over these last year I created a thread somewhere

 

press brake pedal the start button then absolutely nothing except a slight whirring noise.

I've experienced this on another vehicle (Landrover) when the starter motor spins but is not engaging with the flywheel. That was also an intermittent fault. This was an old Lucas unit with a solenoid and was fixed by dismantling, cleaning and lubricating.

It may be possible for someone outside the car to identify the sound source or maybe if you leave the door open and the radio off you might be able to hear where the whirring comes from. Right hand front wheel arch area for the starter motor.

Good luck and let us know how it goes.

 

It’s in the shop and they tested all the wiring, start button earth to starter, battery etc and decided to pull the starter motor out. Hopefully will replace under the extended warranty as there is only one left in the country right now!
in reply to a previous post yes the brake lights come on.
battery only 9 months old and started after 10 days return from vacation.
Also used the reverse procedure of button and brake pedal and that also worked sometimes. Thanks to all will update when starter has been replaced.

 

Starter replaced, so far so good 👍

 

+1 Had this very same issue last year although not so frequent as you. Did full diagnosis, including start security authorization, but ultimately came down to faulty starter motor, solenoid actually. The slight whirring noise is the fuel pump priming. While I agree with the forum stalwarts that starting issues are invariably battery related but there is this very remote possibility that the starter goes bad. Telltale signs are battery checks out good but when you press brake pedal then start button nothing happens but you hear except a slight whirring noise. To verify just put voltmeter between solenoid and ground while doing start sequence and you'll get 12v but no corresponding starter motor engagement.