No Crank , alarm light flickers & steering column speaker clicks

XK8
1

This fault is intermittent and is not due to a faulty battery, The car starts and drivers perfect most times but ever now and again when ignition is switched on the alarm light near gear leaver flickers rather that the normal flashing and at the same time the speaker in the steering column makes a clicking sound. I have also found that when this is in this fault condition No wipers or Headlights . If then left for a while you can often turn on the ignition and start as normal and every thing works again but you can not trust the car due to this fault. No problems with car once started and never fails while driving. This seams to me as if it could be a fault to do with the body computer but looked at connections but no faults found. When the fault starts the alarm lights flickers , speaker clicks , no crank , no exterior lights , locking , unlocking also not normal . also think some dash lights are out , and electric windows jerk slow . When the alarm light stops flickering , speaker stops clicking and car returns to normal operation . Do this have any bad earth / power feeds to do with body computer functions.

Any help please as other xk8 owners must of had this odd fault before ?

Car is 2002 XK8 4.0 V8 N/A Convertible

many thanks in advance for your help.

2

Could well be down to a bad earth point. Use this manual to locate the various grounds in and around the engine bay and check them all.
http://www.jagrepair.com/images/AutoRepairPhotos/jagxk2002.pdf

3

I don’t think this sounds like a module problem because the symptoms are too generalised. I would take a very close look at the high power fuse unit in the boot especially the 250 amp line. Either get a meter across it when the fault is present or just satisfy yourself that all connections are good because it could be that you have a connection going high resistance in that feed. Very difficult to be more specific without further tests but this is where I would start.

It could be a ground problem but there are so many disparate systems affected I can’t see a common point.

image002.jpg

4

I removed the body processor when it was in fault condition and warmed the module lightly with a heat gun. Refitted module and tested and all came back to life. I then read all coding for this module and recoded another second hand module. Car all seams fine now so lucky I had a WDS computer to recode the module.

5

Just a quick update to say car has been perfect since body ecu changed