I got into the car this afternoon (02 2.5 Auto) and all it did was click loudly and every time I stopped trying to start I'd hear a kind of a whizz from the dash, kinda like a spring is being released. Also I could hear the switch in the console clicking, with the traction light flashing. Also after it rests for a few seconds the panel says 'GEARBOX FAULT'. I turn it off, it resets and I go through the same routine.
It's had problems recently, twice going into Limp Mode after I de-select the cruise. My jag guy says it needs a throttle body, but should be OK if I don't use cruise.
I last drove it yesterday with no incidents.
I tried tightening the battery cables and it still just clicked. When my wife gets home I'll try starting with cables.

I've read a few posts here and most lean towards a new battery. Right now it has a Duralast 700a, which I think has plenty of juice left.
I checked the lights and stuff, and nothing was left on.
If I do need a battery, what should I buy?

 

I tried the fuel reset with no success. And now I'm not getting the Gearbox Fault. Just won't start.

 

flyrr100, put a multimeter across the battery. You should see 12.6 VDC. If you see 12.5 VDC or lower, then you have a discharged battery (let me know and we will go from there, but first put the battery on a charger and then see what you have then). With the battery at 12.6 VDC, attempt to start the car while watching the multimeter. Did the battery stay above 12.0 VDC, drop to less than 11.0 VDC, or go to a range between 11.0 and 12.0 VDC. If it is above 12.0, then you most likely have a high resistance battery cable that is leading to your problems (if you want to troubleshoot further, let me know). If it is dropping to below 11.0 VDC, then you most likely have a bad battery or the battery is not fully charged (should be fully charged if the initial reading was 12.6 VDC). If the voltage is staying between 11.0 and 12.0 VDC, then odds are you are looking at a bad starter.

If you need more help, let me know. Based on what you have said, I am placing money on the battery being bad. Not uncommon for this time of year.

 

The car started with a jump from my wife's car last night. I checked the level of the battery acid. One was a little low so I topped it up and took the car for a run. Shut it down and it started right up. But this morning it was back with the clicking.
I think a new battery is the key. Luckily I'm off today so what better than buy a battery!
Watch this space.

 

I decided to have a new battery installed. The guys at the parts store checked the old battery, and after a 25 minute drive to the store it was still only showing 10v.