Active Handling at 75MPH
Thread Starter
6th Gear
Joined: Mar 2022
Posts: 6
Likes: 0
Active Handling at 75MPH
Recently swapped to LG Motorsports C6 Z06 wheels, 19x12 and 18x10s. I'm not sure if this issue is related to the wheel swap or not or if it's just a coincidence but started happening around the same time. Unfortunately I sold my previous set so I can not test it.
When I hit 75MPH my active handling kicks in and does the lovely hard brake. I do not get any notifications or anything on the dash. Just a quick freak out and makes me $*** my pants.
No codes, I took it to a local performance shop and they're stumped.
Hoping someone else has gone thru this and hopefully point me in the right direction.
When I hit 75MPH my active handling kicks in and does the lovely hard brake. I do not get any notifications or anything on the dash. Just a quick freak out and makes me $*** my pants.
No codes, I took it to a local performance shop and they're stumped.
Hoping someone else has gone thru this and hopefully point me in the right direction.
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
Well, ,, Your EBTCM requires a factory tire size % difference between the front and rear wheels. If you changed tire sizes to a ratio outside the OEM Ratio, spec, you will set the DTC and Error message!
Read the DTCs that are set using the C5 Internal DTS Reading Routine.
Please post ALL of the DTCs listed during that test, including the H, C, HC Suffixes.,.
BC
Read the DTCs that are set using the C5 Internal DTS Reading Routine.
Please post ALL of the DTCs listed during that test, including the H, C, HC Suffixes.,.
BC
Thread Starter
6th Gear
Joined: Mar 2022
Posts: 6
Likes: 0
Current setup on wheels and tire sizes18x10 - 275/35/18
19x12 325/30/19
The shop tested the speed sensors with the computer hoping to find a dead spot or one reading off but on their end unfortunately they did not see anything off.
Codes:
10-PCM
-P0102 H
-P0103 H
28-TCS
-C1243 H
40-BCM
-U1096 H
58-SDM
-U1096 H
80-RADIO
-U1096 H
AO-LDCM
-U1096 H
A1-RDCM
-U1096 H
BO-RFA-(1)U1096 H-(2)U1064 H-(3)U1016 H-(4)C2120 H C
Just pulled after taking it home from the shop
19x12 325/30/19
The shop tested the speed sensors with the computer hoping to find a dead spot or one reading off but on their end unfortunately they did not see anything off.
Codes:
10-PCM
-P0102 H
-P0103 H
28-TCS
-C1243 H
40-BCM
-U1096 H
58-SDM
-U1096 H
80-RADIO
-U1096 H
AO-LDCM
-U1096 H
A1-RDCM
-U1096 H
BO-RFA-(1)U1096 H-(2)U1064 H-(3)U1016 H-(4)C2120 H C
Just pulled after taking it home from the shop
Pro
Joined: Oct 2020
Posts: 529
Likes: 197
From: Columbus, MS
With the sizes you provided it's a 1.1" diameter difference. I'm guessing at 75mph you're reaching an individual wheel RPM differential that's triggering the active handling. None of your provided codes seem to be relevant to your issue, so I'm thinking that the system is working normally, but the tire diameter differential is the problem.
Melting Slicks
Joined: Jun 2001
Posts: 2,266
Likes: 549
Most of those codes are from battery disconnect. Also show up after a pcm flash. one is a mass air flow code, might want to clean it. Clear them on your driver information center and see what comes back. Ron B.
Thread Starter
6th Gear
Joined: Mar 2022
Posts: 6
Likes: 0
Not that I'm aware of, like I said I recently added these. The wheels before were from a C6 but not a z so a little smaller in widths. It never happened before only after I put these on, now I could be mistaken and it could be wheel related or just coincidence that it started around the same time.
Recently purchased this C5 and swapped the wheels after owning it for a couple months but I had never experienced it with the previous set up. Sold the old wheels as well, thinking about finding someone to swap with to see if it is in fact wheel related.
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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
100% AGREE!! 
Recommend that you use the D.I.C. and clear ALL the DTCs. The DIC is the best place to read and clear the DTCs. Once you clear them, read them again and work on the new codes that reappear. Is your battery fully charged and in good condition? Recommend that you have it tested.. A weak battery can contribute to excessive random DTCs.
BC 5
Recommend that you use the D.I.C. and clear ALL the DTCs. The DIC is the best place to read and clear the DTCs. Once you clear them, read them again and work on the new codes that reappear. Is your battery fully charged and in good condition? Recommend that you have it tested.. A weak battery can contribute to excessive random DTCs. BC 5
Thread Starter
6th Gear
Joined: Mar 2022
Posts: 6
Likes: 0
100% AGREE!! Recommend that you use the D.I.C. and clear ALL the DTCs. The DIC is the best place to read and clear the DTCs. Once you clear them, read them again and work on the new codes that reappear. Is your battery fully charged and in good condition? Recommend that you have it tested.. A weak battery can contribute to excessive random DTCs.
BC 5
Recommend that you use the D.I.C. and clear ALL the DTCs. The DIC is the best place to read and clear the DTCs. Once you clear them, read them again and work on the new codes that reappear. Is your battery fully charged and in good condition? Recommend that you have it tested.. A weak battery can contribute to excessive random DTCs.BC 5
I have done that, this issue has been going on for quite some time(a couple months?). It always happens at 75, I do not get any codes or warnings. The only consistent codes I get are for the TPMS. From what I'm hearing/seeing the TPMS should not effect this though.
I'm going to continue to test it with traction control off and see if it still happens.
Battery was recently replaced, it did not have those codes before going to the shop.
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
See if you can find another C5 owner locally and see if they will swap tires/wheels temporarily to prove positive that it is not being caused by the size combo of the tires.
. I would for sure try to swap on some tires that are KNOWN to work. Where do you live? Maybe someone will reach out to help. I know that I would.
Other things that can cause this issue are:
A bad Steering Wheel Position Indicator Sensor.
A bad alignment. Is your steering wheel dead straight when you are going straight down the road?
A bad or failing wheel speed answer.
If you clear all those DTCs your telling us the exact same ones, come back the next time you cycle the key and check again?
I will send you a PM. Maybe we can fix some of those DTCs
Bill
. I would for sure try to swap on some tires that are KNOWN to work. Where do you live? Maybe someone will reach out to help. I know that I would.
Other things that can cause this issue are:
A bad Steering Wheel Position Indicator Sensor.
A bad alignment. Is your steering wheel dead straight when you are going straight down the road?
A bad or failing wheel speed answer.
If you clear all those DTCs your telling us the exact same ones, come back the next time you cycle the key and check again?
I will send you a PM. Maybe we can fix some of those DTCs
Bill