I just purchased a 98 black/black vert 6speed, 50000 miles, I will post pictures real soon. I had to upgrade the old c4. anyway, during the testdrive (with active handling turned on), it drove like a bat out of hell, made certain parts of my body wake up, def not a c4 automatic. anyway... they detailed it, then i drove home and while heading down I40 at approx 60 mph, the power disappeared and the car started to slow down, I read in the display "Active Handling Active". I turned the handling off, and power came back and away I went. after a few (10 or so) miles I turned it back on, and all was fine. After I got home I went for a ride a few hrs later and same thing. any ideas, I have lots to learn about the C5. (it did not say Service Active Hanlding) Thanks for your help.IMG]
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I hope I am not getting the Active handling and traction control confused. I'v had a long day.

 

Just a shot but, the only thing I can think of that shows the Active Handling message on the DIC without showing the Service Active Handeling is a condition where one of the inputs is telling the program that you are out of line (sliding, pushing the front end...etc).

If it were a bad sensor, like steering wheel position or wheel speed at one of the wheels, Im pretty sure it would shut AH off, not show that Ah was engaged.

One thing that can screw this system up is if the wheels have been changed from the stock sizes. Basicaly you can change the wheel sizes but you have to maintain a difference (I think its about an inch, but dont quote me on it, search for numerous threads on the subject) between the rear (larger) and front (smaller) sizes.

Most people do this by changing wheels, then selecting a tire with a side wall height that will maintain the required difference between the fronts and rears.

If your car had other than stock sized wheels and the over all difference between the front and the back was enough when cold but so close that when the tires heated up it was out of parameters, that might explain the type of thing you are seeing. The AH would apply rear brakes independently.

I have heard very infrequent complaints of AH engaging on the highway (only one I can remember) but its so infrequent (at least here) that I dont recall what caused it.
Sorry guy.

The same kind of thing can happen with the traction control system. Not enough of a difference between the speed the front wheels are turning as opposed to the rear wheels. If it appears to the the system that they are turning at close to the same speed (which would be the case if you had 18's on the front and the back), it thinks you are spinning the rear wheels (because the stock sizes are larger in back, so must turn slower if not loosing traction) and the Traction control will retard the spark, slowing the car down.

BTW, you may not be aware but the C5 has an on board diagnostic system that you can look at to see if any of the sensors are showing a fault.

Take a look here http://www.stengel.net/diccodes.htm

There are a ton of threads on AH/TC stuff, might try a search for "AH engaged on highway".

Good luck

 

see if you have any codes.if so post 'em. what size tires are you running??

 

Thanks for the right direction. I pulled 1 code and reset.

it was p1516

manf contrl veh. spd
idle speed control
aux input

tire size are rear 275/35 18
front 245/45 17.
I have to go back to dealer, i found the old lug nut lock key for the 85, I have to give it to the new owner so he dont get screwed like I did without one.
I will check back and report later.

 

I'll tell you one thing - if the tires sizes that you posted above are accurate, the front tire is taller than the rear tire by 3mm, meaning that it is spinning SLOWER than the rears. This can be interpreted by the traction control system as wheel spin. You have wheel speed sensors on each wheel, and if it detects that back wheels spinning faster than the fronts, that's wheel spin.

The cause of your problem is that the rear tire aspect ratio is a "35", and stock is a "40". That is one of your issues.

You need a shorter tire in front or a taller tire in the rear. You have to maintain the factory stagger, generally about 1/2" differential works fine. If you have more questions, feel free to PM me and I'll try to explain. BTW - welcome to the world of C5's!

 

Thank you for the info, that explains it. the tires are new, so I will keep them a while, and just turn traction control off. thank you very much for the posts. i have saved tons of money using this forum, and i hope I can help others. thanks for the c5 welcome. it was hard parting with my 85, but my god, the c-5 is a whole new beast. what a rush it is to drive. it has the borla cat back with cross pipe, it sounds just as good as it looks. I will post pictures later on tonight.

 

You might want to reconsider this-first time the rearend tries to come out in front of you you'll wish you had TC.

 

as promised, here are the pics. 1998 6speed convertible, 51000 miles. upgraded from an 85 auto with 86000.
IMG]http://i597.photobucket.com/albums/tt53/mikesvette/100_1461.jpg[/IMG]

 

while i sometimes curse the darn thing (like when going over railroad tracks at a fairly normal speed, lol), i usually come to my senses and realize it's loads better than doing those 360's that used to occur in all my covettes before the advent of traction control.

 

when you hit the button it disables both traction control and active handling i dont think anybody mentioned this if someone did my bad also if you keep the button pressed in for several seconds it will engage competitive mode which disables traction control but active handling is still enabled

 

It looks like a real nice clean car, and I'm sure it's a big upgrade from an '85 C4.

Here's something for you to consider....if you upgrade wheels to an 18/19 or even an all 18 sizing, that rear tire will work on the front and you'll need to do is get tires for the back.....taller I hope. That's the size I run in front on my '98 C5.