Hello Folks and thanks for taking a moment to read this post. So I recently bought a set of fluted alloys for my XK8 off E-bay. The car, a 1996 XK8, that they came off was crushed and had a few choice pieces listed on E-bay. The ECU wasn't listed so I asked if he still had it anyway as my car is a 1996 and I know these ECU's are hard to come by. ( LJA1410AK ) Turns out he had it and said he would sell it to me cheap so I bought it too.
Now the problem is this. I have had my own ECU open in order to solder in new capacitors but what I didn't see in my ECU was this secondary board floating above the main ECU board. I thought it might have been something to do with a convertible but it turns out the 1996 XK8 it came out of was a hard top so I have no idea what it is for. Anybody else know? see pictures.,

 

I have a Gen1 MY99 XK8, in Bahrain, and it doesn’t have that secondary ECU board.

Where is the donor car from? My guess is that it’s additional for USA enviro O2 related EGR etc. related functions, as my Rest of World (ROW) Spec car hasn’t got any O2 sensors in the CATs either.

Well done on posting something I’ve never seen before.

 

Odd. My '98 has the daughter board as I remember having to lift it to get to one of the caps I replaced.

At least some of the '97s have the same.
toaster in bradstuff's thread:
https://www.jaguarforums.com/forum/x...4/#post1603876

greenforest56:
https://www.jaguarforums.com/forum/x...2/#post1780951

99 may be different as that's the AJ27.

 

My early 97 didn't have it.

 

The donor car is from Shefield here in the U.K. Sadly it was crushed so I couldn't get a look at the VCATS label but the LJA1410AK part number would suggest it is a 1996.

 

Have you any idea what the daughter board is for michaelh?

 

And both ECUs have the exact same part number?

I suppose Jaguar might well have simplified the design of the ECU early on while keeping the functionality the same so didn't change the part number.

 

Technically my ECU is part number LJA1410AK\003 but I have no way to determine the final 3 digits without the VCATS label which was crushed with the car. Not that I am looking to swap it for mine rather just trying to work out what the extrra computer board is for. Incidentally I did get the ignition barrel, transponder coil etc so would only need to locate the corresponding transponder module for this ECU to swap if my reasoning is correct? Not sure. So is there another way to determine the final 3 digits without the car and VCATS label?

 

Short answer:- I don't know. Stock answer would be to expand on the module's functionality, or to accommodate that functionality where there are physical constraints on the motherboard shape/size.

However, I don't think there were any significant changes during the very early years that would require extended capability. Also, they're both Denso units so it's not a case of two manufacturers arriving at the same end result via different routes.

Advances in electronics design and manufacturing over time often means that everything can be condensed onto one board and the daughter thus dispensed with. The opposite seems to have happened here, at least until the advent of the AJ27.

From memory (images are blocked at work) there are two large chips on the underside. If you can get a shot of the board it might be possible to determine what they are.

 

97 Here, Mine most certainly has it, it is supposed to be screwed down as well, I can see the threaded holes in your picture where it is supposed to be secured.

 

You can see the screws in the picture as well!

 

Ahh you are right, my bad. I thought when he said floating he was describing the board moving freely in the case when he opened it.