Hello all: I have a 2000 Jaguar XJ8. Great car. Occasionally, on startup, I get a "ASC/Trac Not Available with an ABS warning. On restart these messages usually go away.
Today all was fine and rolling along about 60 mph. No warnings. Then I heard a CLICK sound, and these warning appeared. It is as if a relay energized and turned the warnings on.
I have a new battery, cleaned the wheel sensors, and the ABS module has been resoldered. This is the first time I heard the CLICK. My best guess it emanated from the left (driver's side) maybe aft of the rear door. Hard to be more precise. It only happened once, and this is the first time I could associate the warnings with any other event.
Anyone have any interesting ideas?
Very respectfully, Bob G in Florida.

 

You do realize that there will be a DTC in the ABS module.
If there was a hard fault, the module will log the fault as a code.
Interrogating the module will reveal that code.

bob

 

Hello Bob (aka motorcarman) in Decatur TX. Thank you for the suggestion. I plan to take a look today. I have an iCarSoft i930 scanner, and if there is anything there, I should be able to recover the code.
Very respectfully, Bob G in Florida

 

My vote is for an intermittent failure of the brake light switch. My 2000 did that as well as reverse action of the brake lights. Stepping on the pedal would turn OFF the brake lights if the headlights/taillights were on. Seemed to happen more often if the "on" switch for the cruise control was on. If by habit, you leave the cruise switch on all the time, turn it off for a few days, see if the event happens less frequently.

 

Good morning grantorino62 in Northern California.
Thank you for the suggestion that this might be related to the brake light switch. Yes, I have always had the cruise control button enabled all the time.
I'll try your suggestion and turn it off. Once, when the failure popped up, I did notice the cruise control button's light went off and the cruise control function was disabled.
Can you tell me WHERE the brake light switch is located. Reason: once the failures displayed when I touched the brake pedal on the interstate to slow down. A switch could be the source of the click sound.
Sorry about your 05 XJ8L Super V/8. I also own an 04 XJ8L Super V8 and its a pleasure to take on the road. Rides like a '62 Cadillac.
Very respectfully, Bob G in Florida

 

Attached to a bracket under the dash. A pin on the brake pedal activates it. It also has a switch in it that cancels the cruise control. If both micro switches dont depress at exactly the same time, the ABS will disable and you get the ASC messages as well. Switch is approx. $130 labor about 1 hour.

 

Hello GranTorino62 in Northern California.
This is a GREAT suggestion. As soon as it cools off a little here (daily 95F and 80+ % humidity), I'll look for the switch. What you described is exactly the failure mode of my car. Probably examine and experiment this weekend.
If you don't mind me asking, how did you learn this?
Very respectfully, Bob G in Florida

 

From reading this forum. I've had a 2005 super V/8 and silver 2000 base xj8 as well as a 2005 XK8. The XK8 had the same issue. Unless you're very fit, this switch replacement will give your back a very hard time! Trying to install the one bolt holding it on while depressing the brake pedal is a real pain in the back! I chose to do the XK8 but not my current XJ8. $100 labor and one new switch and picking it up later in the day was IMO the best money I spent that day!