Can someone tell me what the correct reset proceedure is for the Jag X300. As I remember it is to disconnect the negative cable from the battery and touch it to the positive terminal that is still connected. Is this done with the ignition on or off?

Thanks

EZDriver

 

There was a similar reset procedure that I used to use on my old 7 series BMW that involved disconnecting BOTH cables from the battery and then connecting them together for a minute or two. It also seemed to help with sluggish gear changes! However, ON NO ACCOUNT should you connect the negative lead to the positive while the positive is still connected to the battery. You will fry numerous sensitive electronic components in the process, causing no end of problems.

 

It is not possible to "reset" the engine management system if this is what you mean by "the computer". All adapted values in this electronic control unit (ECU) are stored in Non-Voltaile Random Access Memory (NVRAM). It can only be electronically overwritten using a vehilce service diagnostic tool, such as WDS, IDS or a generic tool like Autologic.

Perhaps if you expalined the reason that you are attempting to "reset the computer" it might be possible to provide more advice.

 

Thanks to all. I solved the problem.

EZDriver

 

I had a phone tech nician at Jag help me do a system reset befor. They had me turn the key a set number of times in the door and then do the same at the ignition. This caused all my seat position controls to start to work again and put the engine back to OEM default settings. This did make a difference to the way the engine performed. Wish I remembered the sequence

 

I have a 95 XJ6 which is stuck in limp mode. Before that all of the problems were all related to coil pin tips not touching the plug tops so has been in and out of limp mode before. The plug misfires set the transmission control module to blink the transmission symbol. The dealer could not reset this problem so I replaced the TCM. I would like to force the computer to clear the limp mode if possible. Is this another trip to the dealer? I am an EE with a full engineering lab.

 

semiflex-
Just remove a battery lead and wait a second or two before reconnecting and you will reboot the ecu. . Since you are a double E, you will recognize that shorting the leads is a bunch of crap in that there is already a low impedence across the power leads from the trunk light etc. As XJR engineer pointed out, the hard boot will not reset the codes, but it is known to fix a number of anomolies.

 

Took it to a local euro shop. Root of all evil turned out to be a bad crankshaft angle sensor. Just did a 350 mile test drive and its time to break out the bitters. Cheers

 

I am having problems with my 02 X Type. Shop took the battery out while working on the car. Now the radio doesn't work and yesterday the cruise control disappeared. Any one know how to get these things operating again?

 

Thanks for sharing good information

 

So you don't tell us the problem, and then you don't tell us the solution?

How is anyone supposed to learn from you experience?

 

I reset transmission control module by myself after reading this guide. Read Here

 

ive just been advised to do this on my x300 XJR, by someone on a social media platform.

my issue is that suddenly my electric mirrors don’t adjust and I now have no operation of my steering column… it never went in and out, I suspect due to a broken drive cable as I could hear the motor trying and a clicking sound.
but now I have silence!
my seats work fine.
memory buttons 2&3 move my seat around a bit.
but no steering column or mirro movement.

any tips would be most welcomed 🙏🏼

 

Have you checked fuses?

 

Funny you mention that… my under bonnet fuse map, suggested the fuses I needed to check are in the Left Rear Footwell, so I checked them and all are fine.
Though today I was in a weirdo that had an under bonnet fuse map mounted on a shelf… as I looked at it, it suggested the fuses are in the boot …
I’m a little puzzled but will check all fuses tomorrow… it has gone dark by the time I got home.

thanks for the tip Vee 🙏🏼

 

JagRepair.com - Jaguar Repair Information Resource

Look for the electrical diagrams for your car. It will have all the fuses and locations....accurately.

 

See page 21

X300 1996 LWB.pdf (jagrepair.com)

There is a TSB uprating some fuses

15-16 (jagrepair.com)

Your 97 should have the upgraded external light module as 1 module in the trunk and none up front under te hood

This was source of a lot of the fuse changes