Hi Guys, im just wondering how relevant the serial numbers on an ECU, in this case the gearbox unit for a XJR 4.0 is.


Ive got a P1797 code and the box is up and down through the gears so im looking to change the ECU and gear stick selector module but obviously finding one with an identical serial number isn't really possible.


Any advise would be welcome.

 

It's probably not the module so why do that? Have a look at wiring and connectors.

 

already tried all that, the wiring bells out fine, the ecu's are know to be fragile so its worth a try.

 

In the colonies we are able to have the ECU tested and repaired, if justified, by companies like Automotive Specialties in Tennessee. I would think the same is available in England.

 

Yeah, readily available here, too.

 

As it is here, but at far greater cost and much longer so its easier to just swap one in from my mates extensive spares pile.....I take it the answer to my post is unknown?

 

Yeh, change the battery!

Honestly these cars are super sensitive to voltage, anything lower than 12.5V will likely make ghosts in the machine appear.

What year is the car?

Once you have a big bad Varta in there, do a hard-reset and carry out a shift adaptation procedure on the box.

Modules sensitive? you've a can bus fault with that code, I'd try a fresh battery first.

 

Hi Sean, this saga has been going on for over 12 months now, its 1998 4.0 xjr, she had a new battery as the first attempt to fix her, ive just had the wiring from the box checked and that seams fine, the multi plug connector on the box had been leaking so that was changed at the same time.


Id be interested to know more about the shift adaption procedure you mentioned.