Our 2001s type jaguar's battery (fairly new) keeps going dead after driving it maybe 20 miles or more. What do you think is causing this?

Get the car to an accredited auto electrician and have a load test done on the battery. Brand new batteries are known to fail after installation. Have the alternator out put checked and check the drive belt condition and tension as it may be slipping on the alternator .

bad ground.

many things will cause no start problems could have faulty ignition switch.use test light see if power going to starter if not check ignition fuse to starter.if power going to starter, more likely starter solenoid or starter faulty.if ignition fuse okay and starter and solenoid okay still no start problem could be in the ignition switch or inhibitor switch faulty.code scan for faulty theft security system which will also cause no start conditions.

not exactly,but you need to have the code read that making the fault display...Normally if the car starts jerking u have a tcm issue.This can be caused be several things,but first check the code and let me know what its saying,Does it drive any different?Make sure you get the ****** flused at 30-40k miles its about 300 bucks.Keep me posted

its eaither a bad bettery, or a bad alternater, cuz the battery will hold some charge but if the alternater dont charge the battery it wont last long, hope this helps

This could be caused by many things - but don't panic - as the car is driving okay it is probably a spark plug coil as at your mileage you are due a change. The gearbox fault sign can be caused by the engine misfiring and confusing the gearbox controls - happened to me - took lots of investigations to prove it. Best to get your car on a diagnostics rig and see what faults are recorded. good luck - hope this helps.

One possible cause is water in the boot well. It seeps into the wiring loom and shorts. This would drain the battery. If this is the problem, dry out the well and keep it dry.

Its not codes, what they mean is this. Your car learns how you drive, this information is stored in the Engine computers memory. If the battery is disconnected or is discharged, this memory is lost along with certain other operating parameters. One of the things lost is the "idle point" The cars computer should rewrite this information itself within about 50 miles of driving, if it does not, you may have to disconnect the battery again, leave it disconnected for about 5 minutes and then reconnect. Drive the vehicle to reload the lost information. Now, did you charge the battery whilst it was still connected to the vehicles electrical system..? If you did, you may have damaged the cars computer. This happens due to the higher voltage supplied by all battery chargers.. If disconnecting the battery does not seem to help, take the vehicle to a professional and have the cars computer checked properly.

somewhere in the system, you have a power drain, or a bad battery, try unhooking the battery overnight, and see if it is dead the next day.

You might need to get your electrical system checked beause may have a short that could be draining the battery while you don't drive. Try to get it checked at more than one place so you can find an accurate answer for your problem.