The ECM won't allow the engine to start until the pressure in the braking system is above a certain level. It gets the pressure info from the ABS module. So, since you need to pump the pedal to get enough pressure, there are a couple of possibilities I can think of:

• The ABS module isn't giving accurate information
• The brakes need bleeding

 

On these cars, you have to push the brake pedal very hard to trip the starter interlock switch. Many people suggest pushing and holding the start button first before depressing the brake pedal, which in theory should get you a start as soon as your brake pedal goes down far enough!

 

thanks guys, sometimes it will start first time, will take yur ideas on board. Pulled fuse F19 this evening, should i hear a better roar tomorrow, does this do the car any harm.

 

I don't think it does any harm. It won't affect your emissions either.

 

as i have explained on the start issue, you will see from my thread the car went to limp mode with lights on, wud new battery have fixed this or wud the start issue caused it to do this

 

FYI:

The Jaguar Service Manual 2006-2012 states with the car running minimum voltage from battery MUST be 12.55 volts, or you may very well suffer electrical gremlins from possible modules and connector problems.

 

thanks richzak, new AGM battery at 12.85, when stopped. Saw from previous u pulled the F19 fuse for yur exhaust [mine 2007] do i do this before i start car or when engine on, once i pull fuse to power will it not decide open or shut

 

The valves default to 'open' - with Fuse 19 pulled, the vacuum system that pulls them shut is disabled, so they just stay open.

 

thanks Ngarara, will take out in morning before starting, if the sounds stays the same do'es it mean the valves aren't working, where are the located, can they break off or stick open or shut, hope these question aren't making me look stupid

 

They're at the point where the outboard exhaust outlets leave the rear muffler box. As far as I know, they're always open unless the vacuum system closes them. You should notice the exhaust is louder at moderate revs (1100-3500) than before.

By the way, make sure you get the right fuse 19 - it's the one in the fusebox between the rear seats.

 

thanks, i think yur the human encyclopedia of the xk world

 

Nah, I just read the manual

 

your to modest, pulled f19 fuse today, noise does't seem to be any different, can valves get stuck, mine came with an upgrade back box which is joined underneath to the small boxes, straight forward. It had a real deep roar and slight rumble, especially with exceleration. For some reason it has lost this noise, it's got a bit quiet than before, thats why i pulled the fuse to see a difference, Would give it a odd quick rev now and again, wud i have damage in back box, maybe the baffles.

 

If it isn't the original box, it may not even have the valves.

Was it new? Exhausts 'mature' with use - carbon gets deposited, and the resonant frequencies change, so the exhaust note changes.