Engine ECU

[karga]

I have owned a Jaguar XJ6 3.2 Sport (X300) for the last 21 years.
Last week she broke down on me; The fault turned out to be a waterlogged ECU.
The car is in very good condition and has featured in the magazine on a couple of occasions.
I am struggling to find a replacement for the ECU which is frustrating me somewhat.It is essential I am told, that it is replaced with an ECU with the exact part number: The Part Number is:- LNA141OBF/211 GEMS 6 CONTROL UNIT. I have tried several Jaguar Parts Specialists to no avail.

Can anyone help me source this please ?

Roy

[PeterDavisX300]

Hi Roy

How about this?

https://www.ebay.co.uk/itm/401805676399

Cost you £200. Try Autoreserve parts, they are a great help. Ilkeson Derby, DE7 8EU. That 16 figure item number above, just plug it into ebay. search panel.

By the way, the E and F at the end of the number doesn't make any difference

Hope that helps

[karga]

Thanks for that help Peter, the car is now back in action:

It took me quiet a while to source and get the item: I then had local Auto Electricians fit the replacement: It took a total of 6 weeks !

However the engine is running a little too fast on tick over, around 1300rpm instead of 900rpm and the cooling fan is not switching itself off properly and running at 50%. The Auto Electrical place told me that the ECU needs reprogrammimg to UK specification as the replacement came out of a car from the Netherlands ! ! (even with the same product code) apparently they say ECU's going abroad had to be configured to that country's requirements; The Fault Codes coming up are:- P0413 Air Pump Relay Drive : P1409 EGR Valve Drive Circuit Malfunction : P1401 EGR Position Circuit Out of range :

I've spoken to the local Jaguar dealer to no avail and also to a "so called Jaguar Specialist" and they don't have the equipment to do this on a 26 year old Jag !

Any ideas ?

Cheers

Roy

[PeterDavisX300]

Hi Roy

Sorry, so long since I replied, I no longer have a Jaguar, but still like to keep up with the mark. Re, your problem. You could try a couple of things, You can look this up on the website. Disconnect the battery for more than 2 hours, this might do a re-set alone. There is another thing that can be done, that is, you leave one of the terminals disconnected, and hold that lead onto the other terminal for more than 30 seconds, this does a 'Hard' re-set. JUST REMEMBER, NOT TO HAVE BOTH BATTERY TERMINALS CONNECTED!!! I can't remember whether you disconnect the negative lead from the battery terminal, and hold it onto the positive terminal (with it's lead connected) or, the other way around. This would maybe do the trick. If not, you need someone with an Carsoft i930 reader, about £110. I've got one, but I live in North Scotland, and all my gear now turns toward Mercedes' of the 1980's. Another thing you might check is that the venturi-flap in the inlet side is spotlessly clean, any filth in there, and she'll tick-over on the high side. In fact, I would check that first!

Peter

[karga]

Thanks for that Peter:

I give it a try.

Kind regards

Roy

[Andy P]

I can't remember whether you disconnect the negative lead from the battery terminal, and hold it onto the positive terminal (with it's lead connected) or, the other way around.

Just to clarify,disconnect the NEG cable and hold it on the POS terminal.

Hope that helps.
Good luck and take care.
Andy

[davidr]

Hi Roy - this sounds very similar to an issue I had with my late 4.0 litre XJS. This has an AJ16 engine just like your X300.
My issue was that my ECU had altered its adaption for the idle control. This was fixed by plugging it into an Autologic diagnostic machine and resetting it.
There is a write up in the December 2020 magazine (XJS Section - Page 35) where I explain how the idle control system works and the steps I took to fix it.
There is also a note from Andy Stoddart (Jaguar engineer that developed the engine management system for the AJ16) on page 46 of the February 2021 magazine where he explains the issue better than I did!
I hope that helps
David

[karga]

Thanks for that David.

I have since noticed that the cooling fan is coming on when the car is started and not switching off properly, ie running at 50%. Also the central locking switch in the middle of the dash has the red light flashing and the switch does not operate even though the car locks perfectly with the remote and the alarm system works fine. The central locking system also kicks in on all the doors correctly when the car gets into motion.

This does confirm what the Auto Electrician told me that the ECU needs re-programming to UK spec. I will ring Hollygrove at Ringwood and see if it is worth the drive to get it reset. Will let you know how I get on.

Thanks for that information.
Kind regards
Roy

[davidr]

Roy - it's a long way from Skipton to Ringwood!
If you contact Autplogic they will put you onto a more local dealer who has the right diagnostic equipment.
On the other hand, if you do fancy a trip down to The New Forest then why not?!!

[karga]

Hi David
Sorry Ive been so long on this one.
I was notified of a Jag specialist near York ( Big Cat Garage ) Elvington who had the facility.
I took it over to them in March and they reprogrammed the ECU. Tickover was still a little fast but I was happy with it.
Several weeks have gone by and its been great then suddenly it decided to start "occasionally". At first the engine actually turned over but would not start. I would leave it for a while then go back to it and it would then start ! This went on for a while so I replaced the Crank Shaft Sensor and thought I'd solved the problem. (I'd put one of these on 4 years ago.)
Once the car was running it was no problem and ran well but after standing for a while it would not start again, in fact at this stage the engine is not even turning over now. Complete silence. My immediate thought was the central gear box shift contact but that is working ok. ( I replaced that 3 years ago). I suspected a relay, possibly the fuel pump one in the boot fuse box. That was ok, So I went through all of the relays front and back and inside the fuse boxes in the car checking them with the Multimeter and a 12v battery to ensure the contacts all worked properly. I also checked every single fuse that related to this. I particularly checked the large white Relay located behind the front right headlight as I understand is usually the culprit: I'm running out of ideas now and the car is no longer starting occasionally, in fact not at all, completely dead. I do think it is a minor electrical problem, probably a bad earth somewhere, but where ? ? very frustrating ! ! Any ideas ?