I just got my new... well 2001 VDP... and sometimes when I start the car and drive it I get the ABS and Trac Cntrl 'Not Available' signal on the control display. During these times, these function do not actually work. Other times, when I drive it, there are no malfunction or 'not available' signals, both ABS and Trac work just fine. What is causing this intermittence and how can it be resolved?

 

Have you used the search function?

there are a pile of posts on how to fix this. It could be a faulty connection within the ABS pump module, or a dirty ABS wheel speed sensor. You can clean the sensors, and take out the module and fix this also.

Search and you will find.

 

I had this problem intermittantly about three or four years ago, drove me batty for a bit but was too cheap to go with what the dealer and indi mech's were telling me based on the codes. The warning would flash between ABS and ASC, sometimes there, sometimes not. Hopefully your fix is the same as mine... check your tire pressures and make sure they're the same from side to side. This is 100% reproducable on my car. I can deflate one of the tires just 2lbs, take it for a drive on the freeway for about 5 to 10 minutes, and within a week, if not the next exit, the ABS/ASC warning and abs pump codes and module codes come up. Pump up same tire, and within 1 mile of driving, warning light gone at next start and won't return again unless I let my pressures go off again months later. If I check my tire pressures every month and keep it the side-to-side difference within 2lbs, I go on indefinitely without this warning light. I have a friend with a 2001 xjr and he had the pump and sensors replaced, which seemed to fix it for a while but the warning lights came back after a few months, and now, he checks pressures every month and it hasn't given him a problem for the past 2 years. My guess is the shop he took it to pumped up the tires to normal as a courtesy before giving him back the car...

 

I had my front right wheel bearing replaced today. They also cleaned off my ABS sensor. I have driven the car quite a bit after that (starting the engine multiple times) and the problem has seems to have been resolved. The car now drives and functions splendidly.

 

@technetx

Thats pretty interesting. I get these errors every now and again, and will try the tire pressure trick.

 

@SARC, Yeah, that's one thing that seems to be "unreliable" (for lack of a better term) with these cars is the sensitivity of the sensors or the algorithms used in the computer. My take regarding the ABS/ASC warning is this... the computer bases it's input on the speed differences of the geared rings on each wheel, which has to account for distance differences when turning for example. The calculations are probably based not only on distance, but on time as well. If it detects speed differences for long periods of time (for example, on the highway), that's probably long enough for it to detect a problem. However, the computer sometimes won't throw out a code until it knows "for sure"... so it seems that when it does throw a code or warning light, there's really no specific "event" associated with the light other than the "I think I hit a pothole, or I guess that road was real bouncy, or I guess I went around the corner real fast". The way I look at it, if it's a hardware failure, it wouldn't be intermittant through a long period of time. It would show up rather consistently. It wasn't enough for me for the light to just go off for some reason, I had to find something that was causing it and be able to reproduce it 100% of the time... in my case, with the ABS/ASC alternating warning light, I can make it go on 100% of the time, or keep it off 100% of the time. At least now, if the light does come on again, I know there's a real problem I'd have to look into.

 

@technetx

The only correlation I have been able to make is that it only happens to me when I have someone sitting in the rear of the car...... I was suspecting the rear passenger to be kicking the heelboard (where there are wires and fuses, etc) but after threatening the rear passenger with violence and checking what they were doing, this wasn't the case..... it could be that I have lower tire pressure in the rear, and adding the weight is enough to trip off my computer. Unfortunately (or fortunately depending on your point of view) I don't get the error very often, maybe once per 6 months so it's difficult to try and pin it down. I guess i could deflate a tire a little bit and see if I can reproduce your phenomenon..... Might try at the weekend if I get time. Thanks again for the info.

 

gotta figure 6 months is enough time for any one tire to change it's inflation rate. I do believe the rears are more subjected to speed differences than the fronts, even more so because the right rear get's worn faster than the left (darn supercharger makes me do it lol. I have a digital tire gauge now just because of this particular annoyance. 32lbs fronts, 34lbs rears... keeping it that way and I've kept the warning off for well over 3 years straight ... except for when I waited way too long to replace my last set of tires... they were in really bad shape and no amount of equal inflation was going to make those suckers even!... but ABS/ASC warning light turned off within a mile or two of driving off with my brand new tires