Hi All

What electronic diagnostic tool options are there, if any, that people can recommend for a 1994 XJ40 V12? Itdoesn't matter whether they low or high end (workshop) units.

It seems from a lot of googling there isn’t much and most people are repairing/hacking old jaguar/ford portable diagnostic units. Has anyone tried to reverse engineer these old systems and construct cables to run on a windows PC?

Cheers
Steve

 

Bumpity bump

I guess that the lack of response answers the question. There's no such beast and I'll have to watch out for an old jaguar unit.

Cheers
Steve

 

Hi Rok_Dr,

The XJ40s were OBDI and I do not know if the diagnostic connector was standard or unique to Jaguar. As far as I know, you would need a Jaguar PDU setup in order to do dealer-level diagnostics. Search the forum for "PDU" for threads with information about the system, including photos. Here are a couple of examples:

https://www.jaguarforums.com/forum/g...vs-mpa-128620/
https://www.jaguarforums.com/forum/x...1989-a-126721/

Most of us just get by using the Vehicle Condition Monitor (VCM) to check for stored Diagnostic Trouble Codes (DTCs), since it's simple to use and built in.

Cheers,

Don

 

Hi Don

Many thanks for taking the time to reply. I'm still getting to grips with Lady Penelope and in particular the VCM system. In that respect I hadn't realised exactly what it did provide WRT to diagnostic codes.

As to the dealer level diagnostics, coming from the Land Rover world there are a couple of suppliers who have reverse engineered the landrover system into an affordable black box, which covers the older early 90's vehicles. It seems that there isn't the market in the jaguar world for such a thing.

So at the end of the day I'd better get to grips with the VCM system and keep my eye out for an old jaguar system.


Cheers

Steve

 

Hi Steve,

Here's a quick tutorial on using the VCM to read stored Diagnostic Trouble Codes (DTCs) on late XJ40s:

Turn the key to Position II (ignition ON) but do not start the engine;

Press the VCM button;

Watch for a DTC to appear in the odometer window in the instrument cluster. The codes appear as Fuel Fail and a two-digit number, as in Fuel Fail 89. The codes are defined in the XJ40 Diagnostic Troubleshooting Guide and also in Haynes. I believe both of those references can be downloaded from this forum - if not, send me a private message with your email address and I'll send them to you.

If no code is displayed, press the VCM button again to ensure that no codes are stored.

The system can store multiple codes, but will only display one at a time. To clear the top code and display the next one:

Turn the key to Position II but do not start the engine;

Remove the Instrument Pack fuse in the Center Console Fuse Box. In our '93, it is Fuse 9, the second fuse from the driver's seat (in our LHD car).

Watch the speedometer and tachometer needles until they drop below 0;

Wait several seconds - I usually count to 10 for good measure;

Reinstall the Fuse;

Turn the key to the OFF position.

To check for another stored code, turn the key back to Position II;

Press the VCM button and watch the display;

Repeat until no codes are displayed.


I hope I got all of that correct off the top of my head!

Cheers,

Don

 

Hi Don

Many thanks for that. Its most useful. I guessing you've had to use the VCM on more that a few occasions if you can recite that level of detail of the top of your head .

I found the Hayes manual easily which had the info for the 6 cylinder version. Couldn't locate the other doc you referred to, but it got me thinking and a browse later through the cars owners manuals, I was able to find a DTC list that included the V12. I had read it before but didn't take in the significance. Yep still on the Jaguar learning curve here

Anyway I scanned the relevant info into a PDF attachment.

Cheers

Steve