Soloontario

Somehow I have ended up with an antilock failure while on the track with the brakes hot which ended up triggering the "Service Traction Control" and "Service ABS system" warnings. ( all traction control nannies turned off). Ended up flat spotting a front tire (which just as suggested leads to more flat spotting of the same tire with repeated runs).

Turned off the ignition, computer resets and everything is fine. Go out for 5 laps and it happens again. Later can only handle 2 laps but resets to normal and works ok when cooled or street driven. Figured it was EBCM and sent to Brandon who found other codes but no issue with the unit itself. Now wondering what triggered the problem in the first place.

Can a regular OBD2 code reader find the ABS codes as well?

Open to any and all suggestions.

spazegun2213

I thought the c5's dash could scroll though the ABS codes as well? I may be mistaken, but I think thats how I found my ABS codes the last time.

But if this happens a lot on track the ABS unit may need to be rebuilt. As well, how often are you using the ABS on track? Ideally you should never get into ABS (although in some situations its unavoidable) on track.

Scooter70

Make sure your wheel speed sensors are all working. I had a wire rub on the front rotor at MidOhio and that caused all kinds of ABS issues.

BTW, you can reset the the computer while driving by just turning the key to the Start position. It won't engage the starter. It will just reset it and make the code go away.

moespeeds

No way of knowing what the problem is until you run the codes. Hold OPTIONS and press FUEL 4 times quickly to run the codes. Press OPTIONS again to get into manual and use FUEL and GAUGES to scroll up and down through the categories. Write down the codes, then reset them. My ABS was going nuts on track until I finally just eliminated the wheel speed sensor plugs down by the front brakes, hard wiring them direct.

2MCHPWR

i used competition mode a lot earlier this season. I got tons of messages/errors on the DIC and thought my system was broke/breaking. I got the same messages as you and also "ABS warming up" or something like that.

for a few laps, no messages. then in the middle of a session , they would appear.
they would go away on their own.

Now I don't use comp mode at all and I never get those messages. So I guess while you are learning and want to use comp mode, you will have to deal with the messages. When you are ready to turn off the comp mode/traction control, you won't see them again.

Soloontario

Actually I had all the traction control off. I still find comp mode too instrusive. I did not get into the antilocks much so I was very suprised to all of a sudden hear a squeelling tire which turned out to be my locked R front.

Interesting that I installed the Quantum brake duct kit which requires you to cut the large mounting tab that sandwiches between the hub and the spindle and mounts the ABS sensor connector. It had been fine before this but now the connector is much closer to the hub itself and with the quantum ducts, I know the rotor stays cooler but not so sure about the hubs themselves. I can't think I have too much damage to one of the wires as if they burn out, the system shouldn't reset should it?

moespeeds

Those connectors were the heart of the problem for me. Because of my brake cooling ducts, they were hanging loose as well, and I was randomly losing my ABS on track. Once I cut out the connectors and wired them direct the issue stopped. It would throw a 1255 code for the EBCM, a code for whichever wheel speed sensor was the problem, and sometimes a code indicating a large difference in wheel speed compared to the other sensors. I can't remember the code numbers off the top of my head. Pull your codes, check them out, and then lose those connectors.

skyavonee

I'll be installing ducts in a few weeks - can you provide a few more details on what you did? It sounds like there's a bulky clip connector that you cut out and replaced with a straight wire - is that right? Do you remember the approximate gauge of the wire? Thanks.

moespeeds

I didn't use any wire, just got under there and cut out the plug, then re-attached the stock harness using 2 weather tight crimp on connectors, then heat shrink tubing over all that, then a piece of asphalt loom to protect the wire because I slipped it under the hose clamp that holds the brake duct in place. That keeps it from flopping around under there. The sensor has about 4" of wire, then the plug that goes to the harness. It's just a signal wire, looks to be about 20 ga but you don't need any wire to delete the plug. There are only 2 wires to the speed sensor, not sure if it matters how they go, but I marked them before cutting, just in case.

Bill Dearborn

No need for an OBD2 scanner. You can read all the codes that can happen on the car using the DIC. An OBD2 scanner can only see about 55% of the codes that could exist on the car so they are close to useless.

Bill

sothpaw2

Me, too. And my ___mechanic made matters worse by disconnecting the connector, which caused the wire to totally sever. Of course I knew no ABS all weekend...and this GT3 parks it (50mph in a 75 mph turn in for me) in the fastest turn leading to the Main Straight. Flat spot.

The connector issue can be fixed at the track. I didn't re-wire a thing. The mass of the connector is the issue...it must be completely supported. The wires are flimsy...they must not, in anyway, bear any of the support of the connector. I just zip-tied the connector to the aluminum duct to support it. That's all you have to do.

skyavonee

Well I guess I'll try this first, since it's easy and requires no modification. If I still get problems then I'll cut out the connectors.

moespeeds

BTW The first thing I did was safety wire the connectors to the hose clamp on the brake ducts (it was the closest thing to grab) and it didn't work for me. As soon as I turned the wheel I'd lose the ABS. I also went in there and bent the pins towards the center as shown in another post.

Soloontario

I thought I had the connectors well enough supported but possibly not.

Sure would be great it that is all that needs to be done.

Hard wiring doesn't sound too difficult and even when changing hubs there shouldn't be a big issue, just repeat the work.

Maybe there is something in the design of the hub that requires that big remote tab to be there in the first place. On an F body hub, there is no remote wire and the ABS connector goes straight into the hub. I would think that tab would get in the way of any cooling solution although it keeps the connector further away from the heat at the hub itself.

Thanks for the advice of getting the codes without a reader. Is there any reference as to what each code means?

moespeeds

http://forums.corvetteforum.com/c5-t...odes-dtcs.html

AU N EGL

A few questions:

Do you have brake cooling ducts?

when was the last time you changed bearings?

What brake pads are you using?

What tires are you using? and age?

Soloontario

Yes, I have quantum ducts. Car has about 34,000 miles but not very many track miles (yet) Hubs are original and seem fine to me with no brake pad kickback or much noise. Pads are Carbotech XP 10s and tires are 285/30/18 Hankook RS3s at all 4 corners