fatbillybob

I'm racing today all nannies off. 125mph into brake zone and all 4 wheels lock. Tires hoosier a6 with one qually and one race. Lots of meat left. Flat spot 3 of 4 below circumference lines. One tire to the metal cord. Been hitting brake markers all morning only screwed me once. Abs and active handling service lite on. Restart car goes away. New tires problem does not come back. What happened? That cost me a set of tires!

sperkins

Been there. Makes the wallet hurt and it only gets worse if it continues.
Bill Dearborn helped me track down the issue on a buddy's car.
There should be a history code in the DIC. Check it, report back and I'll give it a stab

Greywolfe

I had my ABS working intermittantly. It ending up being a bad EBCM. I sent to ABSfixer and its been working perfectly for over a year now.

But yeah check your codes first...

naschmitz

Happened to me too. Chevy TechII Scan narrowed it down to my left front wheel speed sensor. Two major flat spots on all the tires, down to the steel belts. Dash lit up like a Christmas tree. Restart the car and it acts like nothing happened, except for the squared off tires.

SouthernSon

I carry extra module in my tool box. I will not run without ABS. My tires don't last long enough as it is.

ABSfixer repaired my first bad one (which I am now running). I believe he eliminates the warm up mode which really puts a hurt on the longevity of the oem one. His bypass makes it last a lot longer.

froggy47

Can you explain re: the warm up mode & how it affects the life of the unit? I did not know there is a warm up on abs. What does warm up do to the abs unit?

Bill Dearborn

All he does is replace the relay with heavier duty relay. If the problem was caused by the original relay being bad that is a permenant fix. If the relay went bad because the pump motor was drawing too much current the problem is masked temporarily and will be back. When the pump is drawing too much current it has to be replaced. Most people dont bother testing the pump so it doesn't get replaced when it should be.
Bill

froggy47

Thanks Bill.

sperkins

codes?

MJM

Probably a wheel speed sensor setting off the warning lights.

Did the lights come on before the incident? Kinda strange to just lock up on you. I ran with the ABS off and the only time I ever locked em up was on purpose during a spin.

RX-Ben

If it is a wheel speed sensor code, check to see if you get rising AC voltage w/increased wheel rpm (can do this by hand). If so, then the problem is likely in the connection.
Cut off the problematic connectors and solder in a direct connection.
If no error, swap in weatherpak connectors. I have done so with no problems.
Because the wheel speed sensor spits out A/C - polarity is not an issue.

redtopz

My T1 car has so many problems right now pretty much everything needs to be replaced. I'm also getting very annoying ABS problems making the car difficult to stop even in normal braking situations (been going on for a while now). Something is making the brake pedal go hard and the car becomes difficult to stop. I think it's the ABS unit or overly sensitive sensors. When I pulled out of impound I had the "Active Handling system is warming up" message and I always run with AH/TC off.

Other than that, I just need a new engine, tranny, and clutch before the next race. Original oem tranny and clutch are finally done and the crate engine I put in this car last year was a lemon.

RX-Ben

what codes? I think/have heard many problems are due to stock connectors. My other hunch is that 1 piece front brakes fry the guts.

I think you can fix it in a systematic manner, but prob amounts to sending your abs brain to get fixed (I had great luck with ATE) and replacing connectors or wheel bearings per the codes.

SouthernSon

Not exactly how I understood it when conversing with him on the phone a couple of years ago. He explained that the warm up/testing mode really put a strain on the module so he eliminates it, or did. Perhaps the HD relay is the fix, as you say. In any case, I have been running nice round tires since the fix.

redtopz

Here are my codes:

C1221, 1222, 1232, 1233, 1234, 1235 for the wheel speed sensors.

C1248 and 1255 for the EBCM.

Also had a steering position error code but didn't record the number.

My engine is cutting power in/out above 5500 rpm at full throttle causing the car to surge like a bucking bronco. I have no idea why. I noticed my injector duty recorded up to 93% at full throttle in 2nd gear. That seems high, but I don't know if it's normal.

Carl, sorry to piggy back on your thread but it seems like a similar issue and we are in the same race group.

Bill

fatbillybob

OK. My codes are:

28TCS:
C1221H 1221-35 all have to do with wheel speed sensors.
C1222H what the fault is I have no clue especially
C1226H since the fault is not there now and I raced
C1226H fine after putting on not flatspotted tires.
C1234H
C1235H
C1248H What is this
C1295H Brake lamp switch open??? BFD!

Thanks guys! And Bill No problem we racers got to figure this stuff out. The ABS is costing us big bucks. This w/E it only cost me tires. It cost KK his car at LongBeach.

RX-Ben

Here are the codes. Check at the connector to see if your rear wheel bearings are putting out A/C voltage when they spin.

Here is info on 1248:

http://forums.corvetteforum.com/c5-t...-a-2001-a.html

fatbillybob

Thanks Ben.

Since everything works right now with no codes I have a WAG theory. I'm thinking that perhaps track rubber worms can hit the connectors to the wheel speed sensors and then those spikes or changes in voltages throw the ABS into a tizzly. I have no other explanation and no way to test the theory. Maybe there is something to the idea of hard wiring the connections so that there can be no interference. The only problem with that is having to break and reattach them all the time for services that seem to need to get done in this area.

Bill's problem seems to be something else with the hard pedal. I would suspect a real fault there. Maybe I have an intermittent fault that will become a real fault with time.

So far I think of us racers in sopac 5/8 of us have had ABS problems

RX-Ben

I have installed weatherpak connectors on at least one corner of my car in place of the stock sensors. The wires are pretty standard (I use high temp) and I think the problem is with the wheel bearings getting hot and issues stemming from that (wire decay). The stock plugs are often the culprit as well.
This is all different than a malfunctioning ABS modulator, which sounds like a possible issue with the hard pedal. Just start testing and replacing stuff. I had intermittent ABS last weekend and it is not fun. And potentially quite expensive.

redtopz

I am starting by sending my ebcm to abs fixer for a rebuild. And replacing my power steering sensor which has a code. I was told the ps sensor influences the abs and active handling system even with all nannies turned off. I will also look at all my hubs and connectors, but they are all SKF and "should" be OK. Thanks for all the tips.