Good morning

Hoping for a few suggestions with what I think might be a security module issue in a 2/93 3.2 liter XJ40, Australian delivery
The problem first appeared intermittently after the battery failed and the car sat unused for about four weeks
Once the battery was replaced the car started and ran fine but the radio didn't light up and nor did the red security light flash
Also the central locking wasn't working but I think that might be a separate issue as it was not working when I bought the car
Next time I went to start it the radio worked and asked me for the code and the security light was flashing again
Since then the security light and radio would fail with increasing regularity
It has now progressed to where it will not start at all on occasions
I've checked the connections to the security module and all looks good there
Battery voltage is good as are all fuses
Any suggestions where else to look or how to check the security module?

Cheers
Ken
2/93 XJ40 3.2 liter

 

The fuse boxes may have cold or cracked solder joints, a lot of late cars suffer from this ...not saying for sure it's this, could also be a module, they fail too usually from the same problem, cold or starved solder joints.

Can be repaired by re-flowing all the joints.

Larry

 

Hi Ken,

Welcome to the Jaguar Forums! It's great to have you with us!

I think Larry's suspicions are well-founded since both the radio and security module receive power from the fuse box at the base of the left A-pillar, but via different fuses.

You can download the wiring schematics for your car at this link:

Jaguar XJ40 Electrical Guide 1993-1994

Cheers,

Don

 

Hi Ken, Rodoz from Victoria. My XJ40 is a 1993 4.0 and I am looking for the elusive security module you speak of. Can you tell me where it lives in the vehicle please ? I have been looking around for it but so far it has eluded me.

Regards from Rooz

 

Hi Rodoz
The module is tucked up inside the rear passenger side fender
You have to take out the boot trim on that side
There is the ABS module that has to come out then you can access the security module
I hope you have better luck with yours than I am with mine, it's really starting to give me nightmares
Cheers
Ken

 

Good morning Ken, thank you for the message, If I have any noteworthy success I will keep you in the loop.

Regards Rodoz