Hey everyone my name is meeri and i recently purchased a 2009 jaguar xf 4.2 supercharged
when i try to start the car all the lights turn on but no crank no start and no click, when i placed it on my scanner i noticed it has no communication with almost any module. i don’t know the

cars history and what has been replaced but can anyone help with what’s going one

 

12.1V is essentially dead battery

 

As above, first thing is to make sure your battery is in good condition and fully charged. These cars are murder on batteries, just sitting for a week will likely result in no start. Jaguar 'solved' the problem by selling a re-badged c-tek battery charger with a kit to permanently wire it into the battery with a power cord out through the boot; I've installed a solar panel on the roof over where my car is parked with a cable in the boot of the car to plug in when I park- this is an excellent solution as the natural on-off diurnal cycle of the solar charger has a reconditioning effect on the battery.

 

Dead enough to cause no communication with all modules, its 12.1 plus a booster pack on it.
Thank you for your response

 

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Dump the starter pack. That is pumping hundreds of amps into your car. I hope there was not more damage done.

Listen to Pod XF. Replace the battery with a new properly charged battery and then see what you have. As posted above the 12.1 VDC is way low. As you know Jaguars are very sensitive to battery conditions and you might be surprised with what a new battery can fix. His suggestion of the battery tender is also a great idea and many use them.

Was this a junk car bought at an auction?
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Wow i learn something new everyday, I'm going to go buy a new battery tomorrow and really hope I could get some promising results.
Could question have you ever heard of a "faulty key" causing these symptoms?

 

Possible yes but let's do the common and simple stuff first.
We have seen new batteries without a full charge so now the recommendation is to charge the new battery before install. These sit on shelves for months before being sold sometimes. But the key is what JagV8 posted above.

JLR wants 12.6 VDC after the car has sat all night. I run a cheap voltmeter that plugs into the cigarette lighter. Now I can pop the console lid open and see what the car has. Very handy and about $15. Yes Jaguar should have given as a volt gauge but they did not!
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As above. don't worry about chasing other problems until you've got the battery sorted, with a fully charged battery in good condition, chances are the other issues will go away. As an example, I had a fuel injector problem a couple of years ago that resulted in difficult starting, i.e. cranking for around 10 seconds. The car threw up all manner of warnings and codes, all very disconcerting but all just the result of the voltage drop from long cranking. Every sensor on the car will be out of whack if there aren't enough volts.
As you've just acquired the car, it'd be worth putting new batteries in the key fobs also.

 

Okay I'm buying a battery, does the quality matter? I plan on buying the cheapest duralast battery that fits my car from autozone, will that work fine?

 

You car=your choice BUT again batteries are so important to these cars. I prefer the Walmart Everstart Platinum for my XJ which uses a H8 size battery. It has a 4 year warranty with 900 CCA. Plus Walmart's are everywhere so service is beyond easy. I "believe" your XF takes the H8 also but do check. It's about $190.
Walmart H8 Battery
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