Just want to say first of all, I'm new on this Forum and the information and people associated with it have been fantastic. I've owned my 02 for two months now and besides the headlight lamp motor issue, the only problem I'm having is with the "Active Control System". I'm not getting the "Service System" message like many others are. The problem begins typically when I'm traveling on a straight and dry highway at about 70 MPH in 5th gear. When I try to accelerate , not spin the tires, the "Active Control Enabled" message appears and I loose power even when I push the petal to the floor. Most of the time, when this happens, if I lift off the gas completely, the message goes away and I regain power. I don't seem to experience this problem at slow speeds. Thanks for reading this and I hope someone can help.

Tom

 

Not familiar with "Active Control Enabled" message.

I didn't know they had one like that.

Are you sure that's what it says?

 

I've read in the forums that the system works off of an accelerometer under the passenger seat and sometimes gets out of sync. Do a search on "resetting active control". That may start you in the right direction.

 

Your post is confusing because there is no such message as "ACTIVE CONTROL ENABLED".

You're either getting :

ACTIVE HANDLING ENGAGED or TRACTION CONTROL ENGAGED

They are two different systems, and come on for different reasons. You will also get a chime when one or both systems engage. Check the message and re-post which of these you're getting.

 

OK, my mistake. The message is "ACTIVE HANDLING ENGAGED" and there is no chime. Maybe the chime is turned off.

 

We are starting to see more and more issues that are a result of fact that the older these cars get, the more mods they have when you buy them used. The new owners who have never owned one previously don't have a clue what's stock and what's not. Does this car have the stock wheels and tire sizes? Did this just start happening or has it been going on since you got it? Anything else you might be able to tell us that would possibly help?

 

OK, assuming that the car is showing that the ACTIVE HANDLING system is engaging ....

This is a complex and sophisticated system. It uses many different inputs to determine whether or not the vehicle is suffering from oversteer or understeer.

Real world example ... the system looks at your steering input (there is a sensor that determines what angle you have the steering wheel turned to) and then compares that angle and road speed (it reads road speed from the same sensor as your speedometer) against input from two sensors ... a yaw rate sensor and an accelerometer.

So .... you're driving down the road at 60 MPH and execute a left turn. The Electronic Brake Control Module (EBCM) immediately recognizes that you're turning (It "senses" the change in steering wheel angle). It immediately looks to the yaw and accelerometer readings to determine if the car is turning at the rate that it expects. If the car is rotating faster than the expected rate (oversteer) or slower than the expected rate (understeer) the EBCM will try (it can't beat the laws of physics ... go into a 30 MPH corner at 60 MPH it cannot keep you on the road) to bring the car's handling in line with your steering input.

You're saying that Active Handling is engaging on a dry straight road when you accelerate. That doesn't fit the profile of when it engages. My guess is that a sensor such as the steering wheel angle sensor is messed up.

First check to see if there are any CURRENT codes stored in the EBCM. See ..

https://www.corvetteforum.com/techti...D=26&TopicID=1

to see the codes, and pay particular attention to any codes that are "C" codes from the EBCM. Post any codes here and some of us with access to the service manuals can look them up and help you further diagnose this problem.

 

Never saw that message until I had the EBCM replaced. I was checking out the handling on the way home and it threw the message a couple of times. Never seen it since. Not sure if it was something to do with the system calibrating. I wasn't pushing that hard but a little more on the spirited side than usual.

 

Check for codes as mentioned above but also take the car out and duplicate the actions you describe but before you take it up to speed put Active Handling in Competition Mode. You do this by pushing and holding the console button for about 15 seconds. Once you see the Competive Handling message on the DIC hit reset on the dash to get your normal messages back.

With the car in Comp Mode do you get the same message or response from the car when you accelerate in 5th at 70?

Once you have done that then disable AH/TC by pushing the console button until you see the Active Handling Off message and then duplicate your actions again.

What happens when the car is in 4th gear and you try to accelerate in either AH On, Comp or AH Off Modes?

Check your wheels to make sure they are on the correct axle. Sometimes people swap front to rear on one or both sides. It sounds stupid but I actually did this while swapping wheels/tires in a hurry at the track and didn't realize it until I noticed the car felt different.

Bill

 

Wow, Lots of stuff to try. I'll post back as soon as I go thru these new tests.

 

I took my baby for a ride just now and wouldn't you know it the message didn't appear at all. Seems like its worst when driveing longer distances. I did make note of the codes though.


AO-LDCM B2282H
B2284H
U1064H

AI-RDCM B2283H
B2287H
B2285H
U1016H

The rest read "NO Codes"
I'll try more driving the next couple of days.

 

These are all History (H) codes, and only involve the Left and Right Door Control Modules (LDCM and RDCM). Use the procedure that tells you how to display the DTC messages to delete these errors. That will give you a "clean slate" to see if the car throws any further codes.

Steve

 

Thanks for all your help guys & gals for all your help. I have more info now. When the Competive Driving Mode is active there is no problem at all. Now for the tire sizes. The door plate says the front tires should be 17" and the rear 18". Well the guy who owned this Vet must have changed them to:
275/35ZR18 all around. Someone suggested the wheel size may be the problem. If it is, can the computer be reprogramed to work with said wheel sizes.

 

Just as I suspected. In a word, no. You'll have to get front tires slightly smaller than the rear. The computer thinks the rears are slipping because they're turning at the same speed as the fronts. They're supposed to be slightly slower from the larger diameter. You can keep the 18 inch rims on the front if you want but you'll have to switch to a 255/35 or around there. Or better yet, go to a Z06 size 295/35 in the rear. That should clear up your problems.

Competetive mode is a more leniant program that allows a little more slipping than stock but it disables traction control altogether.

 

Sorry for my lack of knowledge here. Can I just replace the rear wheels with these Z06 tires or do I have to replace the rear or front wheels also?

 

Lack of knowledge is not a problem when you know where to look for the answers. People who buy these cars used, often don't get the manual with them and as in your case, they purchase them with mods that are not obviously wrong. Then they have to figure out what the problem is. Probably why the guy sold the car to begin with. He made the mod and didn't know what was wrong. All to your benefit as it is an easy fix.

Front or rear. As long as the front diameter is smaller than the rear or preferably in the approximately same ratio as the original stock configuration. I'd suggest the standard 295/35 Z06 rear. It will fit on the 18" rim you already have and it should be enough to clear up your problem. Let us know how it goes.

 

The original (stock) difference front to rear was about 0.9 inch. The T/C and AH systems seem to tolerate as little as 0.4 – 0.5 inch difference.

Your 275/35-18 front tires are approximately 25.6 inches. A 295/35-18 is approximately 26.1 inches so this should work for the rear. Even better would be a 305/35-18 (26.4 inches) if it will fit on your rim.

 

Thanks for your response everyone. The crazy part of this problem is its intermittent. We were out Sat. and no problem untill half of the day was over and we hit a bump at 65mph and there it started "Traction Control Active" It goes away when you lift off the gas. Mostly happens when you get into it hard. But, still intermittent.

 

Wow, same size wheels all the way around, that will cause a problem! What type of wheels are on the car? Normally the rear wheels are at least an inch wider than the front wheels. Sounds like someone put 4 front wheels on the car! Sounds like the handling would be pretty unbalanced, could be dangerous like that.

Like others have said, this can not be programmed out of the car. It must be fixed with the tire size.

 

Wheel size is irrelevant. The overall tire height is what's critical.

You can run 18" wheels all around with no problems, but I'd not suggest running the same tire size all around.

In this case, a switch to 275/40/18 rear tires would work perfect with the 275/35 on the front.