Hi. New to the forum and in desperate need of some help and advice.

About 3 weeks ago, my 2004 3.0 S Type (94,000mls) died and would not turnover, gearbox and parkbrake locked, OBD port dead etc. Car was recovered to Westover Jaguar, main dealers in Poole Dorset.

They initially diagnosed a faulty J Gate Selector Unit and could not get a new one for 10 weeks due to the part manufacturers going bust so obtained a used one and fitted it. This did not cure the problem so my original was refitted. £600 later, a fault was found in the CAN network with a broken cable strand in the front bumper. Wire was replaced and the car came back to life.

I collected the car and drove it home where it sat for a few days until yesterday when i drove it to work. I put my foot down on a hill climb to overtake a truck and the kickdown did not happen so i pressed down further and suddenly the car slammed into a very low gear and the revs went into the red and the car would not shift up a gear until i backed off on the throttle - pretty bad when there was now oncoming traffic!

I have now been out on the empty roads tonight to experiment and found that the car pulls up to 50-55mph fine then if you sit there for a few seconds and then go to accelerate, the performance is very poor. Press the pedal down a bit more and it seems to drop a gear but still no performance - push it some more and it slams into a low gear with a huge thump and hits the redline.

My question is therefore 2 fold. Firstly, could this problem have been caused by the recovery of the vehicle and / or the work that the main dealers carried out (in which case, they should be sorting it out) and has anyone ever come across this before and found a solution?

The car was absolutely perfect with excellent gearchanges and kickdown before being recovered because of this wiring fault so i find it a bit too coincidental that it has gone wrong immediately after. I have spoken to the main dealers who did the repair and they have said that the fault has definately not been caused by anything they have done.

Any help or advice from members of the forum would be greatly appreciated.

Many Thanks

 

First it would be worth reading any (engine) codes in case they show the reason. A £10 OBD tool from ebay will do or get one from someone such as Gendan (will cost more).

Second, it's quite possibly a failing battery and nowadays it's easy to wrongly test them. (It's the computers that get upset so the usual test of amps for starting is useless.)

Third, it could be another wire problem but this one's going to be quite expensive to even research so I'd go for #1 and/or #2.