I own a 1994 XJS V12. I am having issues with the Transmission Lag Warning Light coming on and the vehicle going into Limp Mode where I get no power out of the engine (which also seems to run very hot). I need a OBD1 Scan Tool that I am willing to purchase or even just rent/loan from someone who does have one. I can't seem to find any on the internet and all of the Jaguar contacts I have who work on old cats, don't have one. Please help!

 

Where in the US are you located? There are a few of us here that have the system described below.
The only scan tool that works on the 94 V12 is the Jaguar PDU. It is cumbersome to use, and requires the handheld unit (and I use the "handheld" term loosely), a base station to upload software and data to the PDU for each test to be run, a separate battery adapter to power the PDU when hooked to the car, and the appropriate test cables and adapters to test the various systems. There are no aftermarket scanners that will work, and the later Jaguar WDS won't work either.
If you access the transmission control unit, you can get add a pin the one of the connectors to get it to output blink codes on the dash warning light. Do a search here or on the Jag-lovers forum for instructions. The TCU is located in a different location on coupes and convertibles; which do you have?

 

Thank you for the quick reply! I live in Miami, FL and my XJS is a convertible. I'll start a looking and see if I can buy a PDU or someone in South Florida has one. Would you have any contacts that you suggest in Florida?

 

Try contacting Paul's Jaguar. They do restorations, and might have one or know someone who does. 561-367-0525. They are in Oakland Park, FL.
If you decide to try to buy one, they are getting scarce. Be prepared to spend around $1k for the PDU, base station, cables, vehicle battery adapter, etc. By itself, just the PDU won't do anything. Even harder to find are the test adapters for the HVAC system and the Mk3 Teves ABS system.

This very long thread has the most PDU info I've seen. The first post has links to some training materials.
https://www.jaguarforums.com/forum/xj40-xj81-25/jaguar-pdu-manuals-software-126647/?ispreloading=1

 

Just spoke to Paul, great contact! He's gong to take a look at the car next week, thank you so much.

 

I might know a company on Jupiter Island with a Jaguar PDU if that might be helpful? Let me know if you are interested, because I have to serious look into it. Further, for the long term I am building a PDU set to sell, but you are not helped with it now.

Edit, can't find it . Keep us updated if Paul has got a PDU, I am always interested knowing who and where these units are in the world.

 

So Paul does not have a PDU and he said there was a rare chance that I would find one, and that the software used now doesn't even exist. He said that he specifically only works on my XJS V12's and that he doesn't need a scan tool to figure out what is going on with it. I'll definitely check back in once he takes a look and does a diagnostic. He really seems like he know what he is doing, was a great connection.

 

The software exists, and a bunch of us have it. CD copies are in that link I sent earlier.

 

Not sure if it is true, but people are talking about flashcodes as well. Maybe Paul knows how to do it, or it is fiction, I don't know.

An other option is to build a adaptor cable for your diagnose socket to a 16pin OBD II connector and read it as a X300 V12 (or other car with the same gearbox) .

(started my PDU project after having a engine light on our 1994 6.0 V12 XJS without trip computer, turned out to be a faulty earth strap)

 

Flashcodes are possible for the 6 liter transmission. I rigged up wiring to my TCU so I only have to push a button to read them out. i did that before i got my PDU setup. I don't know if flashes are available for the Mk3 Teves ABS. I have the Mk4 Teves, and the PDU is definitely required for that system, and it interfaces thru the OBD connector, with no other adapter required. The PDU also helped me diagnose seat memory issues.

 

I had a similar situation with my 94 V12. I took it to a dealer who said the current Jag diagnostics did OBD1. Of course, he may have had the old system, but in any case he told me I had a bad solenoid. I replaced all three solenoids and everything worked.

BTW, my tranny has a drain plug, does yours?

 

Could you tell me how to get the flashcodes?

 

This thread on jaglovers, around post 17. Codes are below.
https://forums.jag-lovers.com/t/xj-s...tics/347428/17

 

I think that is good useful information for the topic starter! Great work

 

And? Did you get any further with your car?