Stopped working today. Been working fine, no noise, no vibration, perfect working order, come out of the market, get in the car, turn the key and
nothing. The failure was so quick that I'm thinking electrical? In the morning I'm going to check any fuses and relays...
Any ideas?

Thanks,
Roger

 

Hi Roger,

I think you're right - it does give the impression of an electrical failure. There are several power circuits to the Passive Restraint ECM so you'll have to check all the relevant fuses and relays. The schematic is on pdf page 68 of the Electrical Guide:

Jaguar XJ40 Electrical Guide 1990

Those mechanisms were so fraught with malfunction that if I recall correctly, Jaguar had to eventually extend the manufacturer's coverage to a lifetime warranty, and some of our members have found that in recent years some Jaguar dealers will still honor that warranty if they can get parts. Use the Advanced Search function in the dropdown menu when you click Search above to search the forum for reports from other members. I assume there's a dealer in your area. I know there is one in Sarasota.

Cheers,

Don

 

That belt worked fine today, no trouble whatsoever...?

Sarasota, Fl, been there. Sarasota the town in America where used car dealers sells Rolls and Bentley.
If you're ever in Sarasota have a meal at the Columbia Restaurant in St. Armand's Circle!

 

Could be an intermittent relay or corrosion on the ground point referenced by the PRECM.

We've spent many a Spring Break at Siesta Key, so we know the area well, including St. Armands, but I don't recall ever eating at the Columbia, so thanks for the tip!

Cheers,

Don

 

This will not Fix the Problem. But I recently discovered that if I smack the knee bolster just where my left knee would hit in a collision, I can usually make mine work. As an aside, I have already removed the control unit and tried the whole resolder thing with no noticeable improvement.