About 3 weeks ago my 2004 XK8 started to overheat in stop-and-go traffic -- I was able to get home by turning the heater on and once I got out of traffic temperature came down to where it normally reads.

Took it to the mechanic that has worked on it before and he found that the fans were not coming on, and they were controlled by the engine control module. He was able to locate a used one and called a mobile technician to program it.

Technician says software will not allow him to reprogram so it will work in my car - mechanic reinstalled the original and car runs fine but no fans to pull air through the radiator if it starts to get hot.

I've been told dealer want $2000 for a new module. HELP!

Is there a way to possibly install a switch to turn on the fans if it looks like they will be needed?

Is the some place that can rebuild or repair the module I have? Part number on the used module is MB079700-9114 made by DENSO in Spain.

Any other suggestions????

 

Chances are the PCM (aka ECM) is fine but the mechanic is not.

He's almost certainly got the wrong diagnosis.

It is the PCM that decides when the fan should be on. It relies on what it knows - so its input sensor(s) may be faulty. If it wants the fan on, it usually has a fan control module and tells it to put the fan on - so that module (if your car has one) may be faulty. The module relies on the fan working - so it may be faulty (check fuse(s) & relay(s)).

And so on.

The workshop manual (JTIS) has details and is a free download.

BTW, wrong forum.

 

I've moved your question from General Tech Help to XK8/XKR forum. This is the place to post technical questions about your model.

Graham

 

Yes, your mechanic is in over his head. There is a fan control module and if you do a search of the forum you will get a lot of info. For a quick check of the fans see if they operate when you turn the A/C on.

 

Several weeks ago I asked about my fans not working and the mechanics diagnosis of a bad engine control module.

I had already had him buy a used module and then found out he could not program it nor could the person he used to normally handle tasks like that on Jags and BMW's -- he didn't have any luck either.

After posting my early message and got several replies I had it checked by an ex-Jaguar mechanic that had opened his own shop when the dealer(Woburn Foreign Motors) closed. He diagnosed a bad fan control module and found a used one.

Problem solved -- thanks for the great advice.