hi from the uk .
when you guys do a reset ,whats the thing with the negative cable ,do you take off pos and neg then touch them together .or just take off the neg and touch that to the positive side still connected to the battery.

we just take off the battery .

 

Yes.. Ok, i'll be specific. Remove the negative cable from the battery, and touch the positive terminal, small spark (discharge) then hold for about 5 seconds. Reattach to negative terminal, and that's it.

taking off the battery doesn't immediately clear the memory all modules, there could be some stored power...that's why a touch to + saves the wondering, plus its much quicker.

 

I'd wait a minute at least rather than cause such a spike!!

Also, it will only clear some module(s) - the ones with volatile memory (like the RAM in a PC). It won't clear all the modules with non-volatile memory (EEROM, flash, etc).

The PCM's KAM (keep alive memory) will be cleared (so the PCM will have to re-learn a lot of needed values such as how to idle smoothly and how to detect misfires and if it's already got misfires it will learn bad stuff as being normal!). The TCM (2003/3+ cars) isn't cleared and lots of other modules also aren't. You need a dealer-type OBD tool to clear those.

 

It's not a spike, come'on, you're exaggerating it a little bit. Its smaller than static discharge from shuffling your socked feet on a carpeted floor and opening the refrigerator.

 

It's directly connected to every expensive module in the car. I may or may not be exaggerating but I believe in not taking risks with those modules

 

I agree with jagv8, lots of sensitive electronics, to risky for me. I would spend the 100 euro(?) or so and take it to the dealer to be properly diagnosed then cleared, and I am not a dealer type of guy but sometimes worth the money.

 

Well..... just to clarify - if I actually wanted to clear KAM (e.g. after fixing an O2 sensor or the MAF), I would do so and the cheap and safe way is to disconnect the battery. But I'd do that and wait, i.e. leave the battery off for a few minutes.

But it would already be disconnected during the type of repair I've just mentioned. (If I were doing the repair.)

I'd reconnect swiftly so as to get a good solid connection and have it stay that way. Electrical spikes? No thanks. As few as possible.

 

Hi. I recently did a hard reset on my jaguar 2003 xtype and now it's not turning over when I turn the key. Thing is it was going before I did the hard reset. I've checked all the fuses. You can start the car from the starter motor. Now when I turn the key I have a lot of clicking noise on the dash. Please help.

 

You've posted in a 12 year old thread in the wrong forum. May I suggest starting a new thread of your own here:

https://www.jaguarforums.com/forum/x-type-x400-14/