I know there is an issue where people say the car won't start the first or second tries sometimes.


I've noticed sometimes it also won't shut off when you push the button. If you catch it not shutting off, and keep the button depressed, it will give a "Smart Key not Detected" warning.

I think people previously decided that it was an issue with the brake switch (the pedal needing to be pressed very hard to get it to activate to unlock the starter/ignition). However, is it possible that the root cause of these problems could be an intermittent smart key connectivity issue?

 

To start, press the START button before you step on the brake pedal.

If you inadvertently pump the brake pedal before pressing the START button you may have to stand on the brake pedal with both feet to close the circuit and get it to start.

Weak key battery could be your problem. Easy and cheap to DIY change.

 

Battery might be weak in your key fob try your other key..

 

I've never had the "shut down" issue, but my "no-start on first try" problem has persisted for over a year now. Have gotten use to powering down and trying the the second, which always works.
Mine is in no way related to the process, or the battery.

Vince

 

I have just replaced both key fob batteries and the push the start button first before brake seems to work. However, that is of no help when shutting the car off. Or is it? I forgot, do you have to push the brake to shut off the car? (I can't remember, I haven't driven my XKR for a couple weeks because it's so dirty and I haven't had time to clean it!)

I would think the shutdown issue is related to the startup issue. And that being said, the smart key message that appears when I have trouble shutting down would be a clue as to the real cause, no?

 

>> I forgot, do you have to push the brake to shut off the car?

Nope, just press the button. I *think* you have to be in Park or Neutral however.


>>I haven't driven my XKR for a couple weeks

Maybe your battery (I know its pretty new) has discharged in that time ??
As you know, low battery = strange stuff !

>> because it's so dirty and I haven't had time to clean it!

Jeez ! Is ****-Compulsive hyphenated ????

You could try putting the Smart Key in the 'Docking Station' in the armrest next time. That makes a much better connection to the car, and might give a clue ??

 

I thought the start button not working was just British car charm? As long as it eventually starts...

 

Nope, not in mine, anyway - I just put my foot on the brake & hit Stop. The selector rotates back to Park & everything powers down.

 

Some interestingly divergent theories here!

The Jaguar intended procedure is:




J Gate boxed in red; Rotary boxed in blue.

Graham

 

Haha, it's a combination of things that explains why I haven't driven it. I just was reassigned to a new project at work and am in a construction field office, so I don't want to drive the XKR there and have it get vandalized or damaged. Plus my hours now are all whack! And the weather is getting colder.

I don't think it's my battery as it is an AGM battery and it is only about 6 months old. This problem occured even when I was driving it every day--I was just thinking about it now.

If shutting off the engine only requires pushing the button and not the brake (and also being in park or neutral), then either:

1) shut-off issue not related to the intermittent start issue, or
2) start issue and shut-off issue related, problem not in the brake pedal switch.

I wonder which is more likely!

 

Could be the fob housing itself is defective and the battery makes only intermittent contact. There was a TSB on this and the design was changed. Since yours is a 2007, you might want to buy a new fob shell from your dealer (very inexpensive) and put the electronics from your old SmartKey into it. No need to spend big bucks for a new Smart Key and programming.

 

The no start thing has happened with me a few times, but it has been due to my key fob being in my pants pocket - the pair I was wearing the day before. My initial reaction has always been that there is something wrong with the car, before I realize, with some relief, that it was just me being a knob again.

 

When I first had my 2007 XK, I suffered with regular failure to start at the first attempt. I tried various recommendations for the start procedure with some being more successful than others. I then suffered a total break-down being unable to start at all - engine would crank, fire run for 1 or 2 seconds and then shut down. Off to the dealers who very quickly determined that the Auxiliary Power Module was at fault having suffered "water damage". This unit turns out to be the fancy "fuse box" located behind the the rear seats.

Since changing this unit the car has started first time consistently. Unfortunately, its not a cheap unit to replace but it is certainly worth having it checked if you have persistant starting problems.

 

Yeah, the Auxiliary Junction Box is more than just a fuse box - it's actually an intelligent module with its own firmware.

 

On the 4.2 you are supposed to have the box in P to switch the engine off. You can switch it off in other modes (at least in N anyway, did that by mistake once) but it beeps and wails at you and you get a stern telling-off from the info display on the dashboard.

I occasionally find the car fails to start first time and show an image of the key fob in the dash display with the text "CHECK SMART KEY" or similar. If I switch the car off and then attempt to start it again it's always been OK. I put it down to old battery in the keyfob or just interrupted comms to the car.

 

Yeah, sorry, should have made it clear: the 'return to Park' thing is in the 5.0s with the JaguarDrive rotary selector. There's one exception: if you leave it in Neutral, it will stay in Neutral and the selector knob stays raised for 10 mins (for pull-through carwashes, recovery onto a flatbed truck, etc.).

From the workshop manual:

 

That's funny, in my 12xk, if I leave it in drive when I turn it off; it shifts to Park and the knob retracts.

 

mine does this some times, when starting i press brake pedal then button, on occation it will make a click noise and will start on the second try, wheres the best place to keep key fob when driving, i suppose my pocket, sometimes i just put it in the door pocket. The other morning the car started then died, started second time, wierd. On morning starts idle noise is a bit up and down, is this norm, idle is just under 1000 rpm, goes good all day

 

I had this same problem with my XKR and mines a 2012.My car was acting weird with brake lights staying on and saying key fob signal weak/not available,etc.But how I fixed mine was simply getting my lil brother(He's a certified mechanic) to take my battery out the trunk and clean the battery off were the cables connect and WALAH!My Jag worked like it was brand new again.

 

hello,
I have this issue as well (NA 5.0). Car does not start ca. 1 out of of 3 times, but ALWAYS starts on 2ndattempt, whereas 2ndattempt means RELEASING the BREAK PEDAL and PUSHING it again, so logically connected to the break switch in my case.
=> Is this a break-switch that can be replaced ? (the same that controls break lights etc?).

(This issue is no real problem for now, but I don’t like the idea that e.g. a half defective part could suddenly become a fully defective, and that the car does not start at all at a place where that is not very suitable).

Thanks in advance for helpful advise!