Traction Control Question
Thread Starter
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Traction Control Question
I have a '99 that does not have active handling.
Does anyone know the computer programming amount or percentage of slippage that will set off the traction control?
I am aware of the many posts having to do with front to back tire size differences causing problems if not kept at about 1" ± 0.5", but I am unclear if this is because of the active handling, or the traction control also.
I have run tires that are nearly the same size at 0.3" diameter difference and did not see a problem, so it makes me wonder what is the actual amount that will set off the traction control (not active handling). The reason I am wondering is with only traction control if the same size tire can be used front and rear, but I need to know the programming to determine if that will work.
Thanks.
Does anyone know the computer programming amount or percentage of slippage that will set off the traction control?
I am aware of the many posts having to do with front to back tire size differences causing problems if not kept at about 1" ± 0.5", but I am unclear if this is because of the active handling, or the traction control also.
I have run tires that are nearly the same size at 0.3" diameter difference and did not see a problem, so it makes me wonder what is the actual amount that will set off the traction control (not active handling). The reason I am wondering is with only traction control if the same size tire can be used front and rear, but I need to know the programming to determine if that will work.
Thanks.
Last edited by QCVette; Jun 12, 2013 at 09:45 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Are you getting inadvertent rear wheel traction control activation??
If so, when it happens is there a DIC message indicating the the EBTCM initiated it or does it just happen.
If you read the EBTCM DTCs when it happens (without turning off the ignition, do you see any DTCs?
If so, when it happens is there a DIC message indicating the the EBTCM initiated it or does it just happen.
If you read the EBTCM DTCs when it happens (without turning off the ignition, do you see any DTCs?
Thread Starter
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Thanks for the quick responses.
I might give it a try with some the same size and see what happens. I was just hoping that someone knew how much % of change/slippage was programmed into the computer before it would initiate traction control.
I have not had any traction control activation and no DIC messages. I was just wondering if the active handling was the more sensitive between AH and TC, and if so how much can you get away with on only the TC.
I do not think there is a rigid formula to determine this. There have been a number of posts on the forum over the years from members that have/are running the same size tires front and rear and do not experience problems. And there are plenty of posts from members with less than a 1/2" delta that experience problems. Almost seems like a try it and see when you get to less than 1/2" delta. The problem is actually traction control and not AH problem. Traction control thinks the rear tires are slipping and attempts to correct that by applying the anti-lock brakes and backing out throttle and timing.
Are you getting inadvertent rear wheel traction control activation??
If so, when it happens is there a DIC message indicating the the EBTCM initiated it or does it just happen.
If you read the EBTCM DTCs when it happens (without turning off the ignition, do you see any DTCs?
If so, when it happens is there a DIC message indicating the the EBTCM initiated it or does it just happen.
If you read the EBTCM DTCs when it happens (without turning off the ignition, do you see any DTCs?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
In my honest opinion,,,,,,,, AH is WAY more sensitive than TC..
AH uses accelerometers for Acceleration and Yaw where TC uses WSS for activation..
AH WINS over TC
TC is a little more forgiving!
BC
AH uses accelerometers for Acceleration and Yaw where TC uses WSS for activation..
AH WINS over TC
TC is a little more forgiving!
BC
Thread Starter
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I didn't know the AH uses accelerometers. I never thought about it, but I assumed it used the WSS for both AH and TC.
I have a set of C4 wheels and tires that are all 4 the same size. I might give them a try and see what happens. If it doesn't work, at least I can just turn off the TC.
Thanks again.
Edit:
Thinking about it a little more, I think I learned something.
Since the Active Handling uses accelerometers to monitor vehicle dynamics and even though it may be more sensitive, the tire size has no effect at all on AH since the wheel speed is not an input to it. I previously thought that it was more sensitive and therefore the tire sizes had more effect on it. I was wrong.
That also means that all C5's are subject to the tire stagger requirements since they all have TC. (although it seems to vary somewhat as to how much you can get away with before TC issues)
I have a set of C4 wheels and tires that are all 4 the same size. I might give them a try and see what happens. If it doesn't work, at least I can just turn off the TC.
Thanks again.
Edit:
Thinking about it a little more, I think I learned something.
Since the Active Handling uses accelerometers to monitor vehicle dynamics and even though it may be more sensitive, the tire size has no effect at all on AH since the wheel speed is not an input to it. I previously thought that it was more sensitive and therefore the tire sizes had more effect on it. I was wrong.
That also means that all C5's are subject to the tire stagger requirements since they all have TC. (although it seems to vary somewhat as to how much you can get away with before TC issues)
Last edited by QCVette; Jun 13, 2013 at 10:54 AM.
