ABS wheel sensors - calling all electronic gurus!

[beeman]

I had a conversation with Shane on Sunday about ABS options for the GTM. He has a customer car that needs an ABS system. I'm interested in a better option than the C5 brick.
The C5 ABS/EBCM is generally regarded as a crappy system that is prone to what C5 guys and girls call "ice-mode" (EBCM freaks out and brake pedal goes hard, you have no brakes! -on the track primarily-). Lots of stories of C5 track cars blowing through a corner on the track because the EBCM got confused and blocked flow to the calipers, no brakes and a rock hard pedal.

So one option I've talked to Shane about is the M3 system, which is able to operate independently of a PCM. Bulletproof and much 'smarter' than the GM system, proven as a swap into countless track cars.

The 1st issue with it is that the components are very expensive even used. Figure 1500-2000 just for the components, plus wiring etc. The second issue is that the C5 wheel sensors are incompatible with the BMW ABS unit. This requires replacement of the hubs with ZR1 hubs with the yellow pigtail connectors. This is not inexpensive, but additionally, as Shane pointed out, the spline count on the rears is different from the stock C5 rear hub spline count. This requires custom axles at $600-1000 and I believe different outer CVs? So were getting in the $4k-$5k dollar range just to get the BMW up and running.

One option I recently became aware of is the late model Mustang s197 ABS unit, out of 2005-2014 Mustangs. Dirt cheap, robust, and my understanding is that it will operate independently of a PCM. I recently became aware that Vorshlag has this system up and running in one of their C5 track cars, and it is light years ahead of the GM unit. But they had to do the changes above, same requirements as the BMW units so lots of peripheral costs to make this work in the GTM.

So my question is this-
I believe the C5 has passive hub sensors for the ABS, vs more modern active sensors which are compatible with the BMW and Mustang ABS units. Is this terminology correct? or maybe Hall sensor vs AC sensor?

For you electronic wizards, is there a converter that could interpret the C5 hub sensor into something that the newer ABS units could function with?

My other idea is, can the rear vss tone ring that we install at the gearbox flange feed a sensor that is compatible with the newer units? This would let us keep our rear hub, CVs, axles, etc which is a huge cost savings. Still would have to swap out the front hubs but that is peanuts in comparison to revamping the rear. Just run a tone ring on both axles to feed a signal to the ABS unit.

Who wants to be a GTM hero?

[crash]

You must understand that you are messing with THE most critical system in the car. The brakes. I spoke with Shane about this situation at length, and passed along some info to a guy that was trying to get us to run the BMW system in the FFR PDG GTM. The one thing I said HAD to be a part of any system we put on the GTM was a switch where we could instantly turn the system off and the brakes would go back to being just exactly as they were before any ABS anything was installed. He assured me that the BMW unit would do this, but he knew of no others that would. I think you may want to consider this "request" when talking about any add on ABS system.

I have not personally experienced the BMW system...yet...but by the sounds of it, it is worth the extra $$. Of course we already have all the "extra" components you are talking about since we have already "upgraded" those for various other reasons. I think your $4k-$5k estimate may be a bit light. Quality ABS is pricey.

We had already changed over to the C5 ZR-1 hubs many years ago because they were just a bit less expensive than the SKF Comp hubs and at the time I think our electronics guy said that there was a converter that he wanted to try. I will see if I can find an email.

[beeman]

Thanks for the input Mike.
I'm hearing that this Mustang s197 unit is every bit as capable as the BMW unit, but much cheaper and much more available.
The ZR1 hubs are C6 correct? Or are they upgraded C5?

Who understands how the hub sensors work? Can a signal be sent with a tone ring? If so, I think we have a simple solution with front ZR1 hubs and the s197 abs!

[beeman]

I'm assuming that the C5 has a tone ring buried in the rear hub assembly? No way to mate a Mustang sensor with it?

Here's the mustang rear tone ring, $30. Where could it be mounted on the GTM axle?
https://www.getoemparts.com/oem-parts/ford-rear-sensor-ring-5r3z2c189aa?origin=pla&gclid=CjwKCAiA1aiMBhAUEiwACw25MZ1DrVJQS_3mIOeBHmcL Cn4WrV3mCteNcbh4lVH5T5Z4G3e9P0xQoxoCESAQAvD_BwE

Here's a s197 front hub
155855

[beeman]

Do the front and rear tone rings have to have the same # of teeth for abs to work properly?

[VRaptor SpeedWorks, LLC]

I've seriously spent DAYS on this project now....and just late yesterday ended up buying all of the needed parts. We will see if they all work together. One of the main issues was the rear hubs/wheel speed sensors. I talked to a source that beeman gave me on the Mustang ABS unit. Sounds like they are in the exact same situation I'm in right now....they are trying to adapt the Mustang unit to work on a C5 corvette. They said they may have a "kit" put together for that in the next few months. I don't have a few months to wait and hope, so ended up committing to the BMW ABS unit. The crucial part that I thought was going to be a huge $$$ issue was the rear hubs......the idea that all of the newer rear hubs were 33 spline vs the 30 spline axle that's on this car....which would have required me to replace the hubs AND the axles and get custom axles made just to get this ABS working. The guy beeman had me contact told me that there are 30 spline hubs available that do have the proper wheel speed sensors to operate the BMW ABS. I found them and got them on order, so we will see if all of this will work together.

[beeman]

Good deal, Shane!
Your client will love the BMW unit compared to the GM unit.

[crash]

Shane- If you could post or email me that hub part number I would appreciate that.

[beeman]

Here's a nice overview of the MK60 BMW system swap.
https://3dmmotorsport.com/blogs/mk60-standalone-abs

The key items required for installation are:

Wheel speed sensors (one per wheel)
Pressure sensors (measuring master cylinder outlet pressures for the front and rear outlets)
Yaw/Acceleration sensor
Signal to the ABS system that the brake pedal is pressed (this is typically accomplished using whatever controls the brake lights)
12v power
Ground

155897

[Ajzride]

Have you looked into the Subaru units? Several people have transferred them into their 818, even when using an aftermarket ECU I believe.

[VRaptor SpeedWorks, LLC]

Shane- If you could post or email me that hub part number I would appreciate that.

Here is what I ordered (Rock Auto):

ULTRA-POWER 513291 (2)
ULTRA-POWER 512441 (2)

The 512441 part number are the rears. RA has "30-spline" right in the description. I'm told that the correct wheel sensors are indicated by a yellow sleeve over the sensor wires, which...if the photos on the RA website are accurate, those definitely have the yellow sleeve. I guess we will see when the arrive here if that is the case. I won't truly know if all of this works until we get the whole system wired and plumbed and can drive it?

[beeman]

155898

This guy recommends mounting the pump at an angle, same way BMW did it, look into that.

155899

This supposedly allows you to properly bleed the system, test the brake application of each wheel, check wheel speed sensor outputs etc.
https://www.amazon.com/gp/product/B01KK0M5CK/

Here's a wiring guide
https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/225507d1621380277-mk60-abs-installation-guide-mk60-wiring-plan.pdf

[VRaptor SpeedWorks, LLC]

Have you looked into the Subaru units? Several people have transferred them into their 818, even when using an aftermarket ECU I believe.

I have not looked into that, but that would be a case where you know the ABS unit is compatible with the wheel sensors since they all come from the same car....they're all Subaru parts meant to work together. Would the Subaru unit work with either the old C5 or new C6 hubs?....that's likely the question that no one right now can answer. ...which is the only reason I committed to the BMW unit.....people have already installed and verified that the BMW unit is compatible with the newer C6 wheel speed sensors.

[beeman]

Shane- are you not getting the front ZR1 hub?

ULTRA-POWER 513304
Front; ZR1

ULTRA-POWER 513291
Front; 427; Base Model; GRAND SPORT; Z06

[VRaptor SpeedWorks, LLC]

155898

This guy recommends mounting the pump at an angle, same way BMW did it, look into that.

155899

This supposedly allows you to properly bleed the system, test the brake application of each wheel, check wheel speed sensor outputs etc.
https://www.amazon.com/gp/product/B01KK0M5CK/

Here's a wiring guide
https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/225507d1621380277-mk60-abs-installation-guide-mk60-wiring-plan.pdf


Excellent info....thanks!!

[VRaptor SpeedWorks, LLC]

Shane- are you not getting the front ZR1 hub?

ULTRA-POWER 513304
Front; ZR1

ULTRA-POWER 513291
Front; 427; Base Model; GRAND SPORT; Z06

Both descriptions show that they are for "base model". Since the rears can be 30 spline (base model) or 33 spline (ZR1) and I have no idea if the base model (30 spline) rears would put out the same signal as the ZR1 fronts, I decided to make sure all 4 hubs were matching "base model" hubs....which I would assume would mean they all have matching sensor outputs. What if the base model hubs and ZR1 hubs have different pulse counts per revolution and I mix and match the front and rears?....I'm thinking that would not be a good deal, so decided to play it as safe as I can considering I have no way of actually knowing if there is a pulse count difference between the 2.

[beeman]

What I'm seeing, generically, is that the front and rear tone ring teeth numbers should match for ABS.
I'm concerned that the 'base' hub sends the passive signal, while the ZR1 sends the more modern 'active' signal? Did your contact at that shop we talked about confirm those hubs?

[VRaptor SpeedWorks, LLC]

I'm just going by the year of fitment and the photos that show the yellow sleeve. There are some hubs listed there that don't show the yellow sleeve over the wires in the photos......I assume those are for pre-2010 cars? It's possible that the photos on their website don't exactly match the parts, and in that case, I'll have to send them back and see what else I can find.

[VRaptor SpeedWorks, LLC]

155907

155908

[beeman]

Reading some more, passive sensors do not supply power to the sensors, active sensors are powered. Hall sensors are a subset of Active sensors that are much more sensitive.
Some active sensors read off a metal tone ring, others read off a smooth ring that has embedded alternating pole magnets.
Measuring resistance through a passive sensor should give you a resistance reading, ohm meter on active sensor will show open circuit. Typical resistance will be somewhere between 1,000-2,500 ohms. Shane- maybe you could test this when your units arrive.

ADVANTAGES OF ACTIVE SENSORS
Wheel speed detection from standstill. This facilitates speed measurements down to 0.1 km/h, which is relevant to traction control systems (TCS) as soon as the vehicle accelerates from a stop.
The Hall sensors detect forward and backward movements.
The sensor is smaller and lighter in design.
The lack of impulse wheels simplifies the power transfer linkage.
Sensitivity to electromagnetic interference is less pronounced.
Changes in the air gap between the sensor and magnetic ring have no direct impact on the signal.
Virtual insensitivity to vibrations and fluctuations in temperature.

Testing an Active Speed Sensor
The best tool for testing the active speed sensor is a good scanner, preferably one that can show the separate speed sensors in graph form. A lab scope is probably the best for a more precise answer and can be attached directly at the sensor to read the individual sensors or wires rather than the entire system as with the scanner. But if you’re looking for a quick test to determine if just the speed sensor is in working order you can make a quick little tester yourself.

LED Tester
You'll need a 220 ohm resistor, an LED and a 12v battery source. Disconnect the sensor from the car, (DO NOT TRY THIS WITH IT HOOKED UP!) hook up the battery to one side of the sensor leads, the other lead from the sensor is hooked up to your resistor and LED, the remaining lead from your LED should return to the battery. An LED is polarity conscious, be sure to have the current flowing in the right direction or it won’t light up at all. (The sensor doesn’t care which direction just the LED does). What you’ll see as you spin the wheel is your LED blinking on and off with an increasing and decreasing blink as the wheel speed changes.

This is one of those times when the old school test light isn’t going to help you out at all; in fact, it might create more of a problem. Your scope or your scanner on these types of sensors is the better choice. But, this quick little LED tester might help you with your diagnostics; it won’t test the entire system but will confirm if the speed sensor is functioning. Testing is always better when you have more than one method to determine the condition of a component. In this case, a scanner, a scope, or a homemade LED tester can help you in diagnosing these active speed sensors.

[beeman]

The Mk60 sensors are active but they are not Hall effect. They are the Magneto Resistive (MR) type.
The resistance of the sensor changes as the teeth pass by. One of the two wires is 12V supplied by the ABS unit, the other wire is the output around 10V and the signal is represented by the the current -> 14mA current for high, 7mA for low defining the square wave.

[KGTM]

One other way might be use voltmeter in AC mode, set to low scale like 1V or so max, spin wheel if passive you will see around some ac voltage, typical is about .5 RMS and faster spins will make it to 1 and higher.
if active Should not see any AC voltage.

Mostafa

[beeman]

Thanks KGTM. Your name came up when Shane and I were talking about who would have the electronic know - how about this!
I found this site earlier today, a couple of the devices looked VERY promising. Unfortunately, the developer says it will not work for ABS. But some of you may find other uses for the modules. They convert passive signal to active

https://sirhclabs.com/
Here's our email discussion :


Looking to convert my passive wheel sensors on all 4 corners to square sine wave. Could you please tell me the difference between your VR to Hall sensor converter dual-channel versus your speed sensor adapter version 1 and 2? Do they both function similarly with the only downside to the dual-channel being the need for 5v input (I'm assuming from a 12v-5v converter)?
Thanks!
Dave


Hi Dave,

The Speed Sensor Adapter V2 works with passive and active speed sensors, they have a built-in 5V regulator that is very robust, and the output can be configured for 0-5V or 0-10V square wave. It can also be configured for a "noise reduction" mode which can help eliminate erroneous outputs caused by electrical noise while the vehicle is stationary.

The VR To Hall Converters (single and dual channel) only work with passive sensors, they require a 5V power source, they only output a 0-5V square wave, and you have to be able to solder wires to the boards. The chips are pretty sensitive to supply voltage and require a clean 5V supply to prevent the chip from being damaged.

Both devices are based on the same chips (MAX992x).

Christopher Kircher
SIRHC Labs LLC

Thank you!
Is the v2 better than the v1 for my purpose of running a newer ABS unit with older VR hubs? Am I stuck buying 4 units, one for each corner?
Thanks again!
Dave

The original Speed Sensor Adapter (V1) was discontinued around a year ago. A few new features were added to the V2 that allow compatibility with more sensors and configurable output amplitude. The current product offerings are the Speed Sensor Adapter V2, single channel VR to Hall Converter, and dual channel VR to Hall Converter.

Your options with 4 sensors would be:

4x Speed Sensor Adapter V2
4x Single Channel VR To Hall Converter
2x Dual Channel VR To Hall Converter.

However, if you are trying to connect the sensors to an ABS module that was designed for active sensors none of these options will work. The active ABS sensors output a very strange square wave, it has an amplitude of around 0.5V and some kind of DC offset (usually 1V or 11V). I do not produce nor am I aware of any products that will be able to convert a passive sensor signal into this type of waveform.


Christopher Kircher
SIRHC Labs LLC

[crash]

We looked into these converters and the issue IIRC with both the converters and the passive sensors is that they do not register wheel position. Apparently the ZR-1 hubs have a double notch or something of the like to signify actual wheel position. This is what we have been told, although we have not verified. We already had a couple sets of the ZR-1 hubs so we donated those to the development project that we participated in previously and we are told they work properly with the BMW ABS unit. The issue for Shane and many others is the 33 spline ZR-1 hub requires all the other axle components to be changed over. If he, or anyone else, can find a 30 spline "off the shelf" hub with active sensors that will save everyone a bunch of $$$.

Hopefully Rock Auto is posting actually what they are selling. I find that many MANY times posters on Amazon list wheel hubs for a Corvette and have no idea what the actual differences are. They use whatever picture they have but then send out something entirely different. I can tell you that I use Amazon for purchasing hubs because if the listing is wrong you either have a no hassle return or they "encourage" the seller to just have you keep what they sent you in error and refund your costs.

It would be great if Shane finds this part that I have not been able to find as of yet. I do have a chart of available hubs that I use at this point and I would love to add another hub on there that works for our customers. I will be watching this thread with anticipation.

[VRaptor SpeedWorks, LLC]

Good news/bad news on the hubs that just arrived:

The really good news is that the rears:

ULTRA-POWER 512441 (2)

Look to be the correct parts. They are indeed 30 spline and do have the yellow sleeve over the sensor wires AND I measure no continuity between the 2 sensor wires. On the stock C5 hubs that are on the car now, those measure about 1050 ohms across the sensor wires.

The bad news...the front hubs do not have the yellow sleeve over the sensor wires. They are sealed up in a bag and I'm not even going to bother breaking the bag open to check them. I'm going to have to return those.

[VRaptor SpeedWorks, LLC]

So....on this page:

https://www.rockauto.com/en/catalog/chevrolet,2012,corvette,6.2l+v8,1501819,brake+&+wheel+hub,wheel+bearing+&+hub,1636

You think the ZR1 front hubs 513304 (4th item down from the top) is what I need?

[crash]

I have a box from the last time I ordered ZR-1 hubs with the following numbers on it:

ACD# RW20-131
GM# 25933291

Certainly there could be other numbers that are valid, but those are the ones I have here.

I just have to ask, if you got the correct hubs for the rear, why not order those same hubs for the front? Hubs are all the same except the early ones that had blanking caps on the fronts. Fronts, rears, lefts and rights are all the same hub...or can be.

[VRaptor SpeedWorks, LLC]

Good point...that might be the best course of action....

[beeman]

Shane does it look like those hubs will fit the front too?

[VRaptor SpeedWorks, LLC]

Like Crash said, there's no reason they can't....the knuckles are all the same part front and rear. I always wondered if the axle nut on the rears played a part on the pre-load of the wheel bearings and the pressed in caps on the fronts took the place of the axle nut on the front to pre-load the bearings, but looking thru the parts on RockAuto, they do look like they have photos of the splined centers labeled as "front" hubs, so apparently....like Crash said....it doesn't matter.

[KGTM]

Have had a very busy week after Sema so I missed some of this, not that I can help much.
for what I see most active sensor hall effect or Magneto Resistive will need ground, so the hub may need to be grounded, you may be able to notice this is true by checking each lead to hub metal and see if there is any resistance, I would check in both direction with voltmeter.

for most part they seem to work with current thought them, 10ma open and may be double when close, it is possible this can be down with two wires and not 3 (gnd case), if I had one it would be easy to find out.

BTW I think my rear hub is C5 and had 48 teeth, not ture? although ECU does not put out 48 teeth output.

Mostafa

[doug_porsche]

I don't want to hijack this thread, but my question is closely relate.

I want to replace the wheel studs on my car. How much do I need to disassemble on the rear to do that?

If it can't be answered with a sentence or two, I can start a new thread.

[Shoeless]

I don't want to hijack this thread, but my question is closely relate.

I want to replace the wheel studs on my car. How much do I need to disassemble on the rear to do that?

If it can't be answered with a sentence or two, I can start a new thread.

Remove axles, remove brakes, remove spindle from at a minimum the lower control arm, use I believe a T55 torqs socket to remove hub from spindle, replace studs, and then do this all in reverse order.

[VRaptor SpeedWorks, LLC]

Well, we discovered an issue if anyone heads down this same path. The hub flange that the wheel mounts to is thicker on these new hubs than the C5 hubs. All of the thickness is on the inboard side. Not sure if this is the way it's supposed to be, but all 3 bolts that hold the hub to the knuckle are the same length. The 2 top bolts tighten down against the back of the knuckle. The bottom bolt is countersunk behind the lower ball joint stud.....so that bolt sticks thru the other side farther than the top 2 bolts. With the added thickness of the wheel flange, that bottom hub bolt ends up sticking out far enough that the end of the threads hit the back of the wheel studs. So we are having to take the rear hubs all back apart to get to that bottom hub bolt so we can get the bolt out and cut it down so the threads clear the wheel studs......not fun.

[crash]

Well, we discovered an issue if anyone heads down this same path. The hub flange that the wheel mounts to is thicker on these new hubs than the C5 hubs. All of the thickness is on the inboard side. Not sure if this is the way it's supposed to be, but all 3 bolts that hold the hub to the knuckle are the same length. The 2 top bolts tighten down against the back of the knuckle. The bottom bolt is countersunk behind the lower ball joint stud.....so that bolt sticks thru the other side farther than the top 2 bolts. With the added thickness of the wheel flange, that bottom hub bolt ends up sticking out far enough that the end of the threads hit the back of the wheel studs. So we are having to take the rear hubs all back apart to get to that bottom hub bolt so we can get the bolt out and cut it down so the threads clear the wheel studs......not fun.

Yes we have had this issue as well. I am switching over to socket cap screws going forward, but the taller heads on those now create an issue for the two non counter bored bolts. I was looking at shortening the heads of the bolts, but instead I am going to try counter boring the two bolt holes slightly. Not as much as the lower as I do not want to effect strength of the upright/knuckle, but enough that I don't have interference issues going forward. I prefer the socket cap screws because they are widely available, cheap, and don't require a specialty tool to work with.

I will note in regards to the flange thickness issue that some hub styles use counter bored wheel studs and some do not. This will contribute to the interference issues you are experiencing as well if you use something like the ZL-1 hubs that do not have counter bored studs. I will also note that the newer hubs have a larger outside flange diameter. Likely because the stud diameter increased to 14mm on the later hubs from the OEM.

I scratch my head constantly when I look at the changes that were made on the hubs and wonder why GM did not just make them strong, big and beefy from the beginning. Penny wise and pound foolish if you ask me.

EDIT:

I reread what I posted and it does not seem clear as to how my post directly relates to Shane's issue, so here is some clarification.

The other reason to change over to the socket cap screws is that you can then use two different length bolts and this eliminates the issue you are seeing because the OEM bolts are all the same length and, as you know, the counter bored lower bolt can become a problem. Using the shorter length socket cap screw fixes this but then presents the other problems listed above on the axle side of the system. If one just changed the counter bored bolt over to a shorter socket cap screw that would quickly and easily fix all the interference issues, but then you would need two different tools to change a hub out. No matter how this issue is addressed there are pros and cons. Shortening the OEM, as you are apparently doing, is probably the best solution if you are not planning on having to change out the hubs regularly like we do.

[beeman]

Shane- could you post a couple of pics of what you are describing? Is the fix simply cutting some threads off of one of the bolts? Is this an issue on all 4 corners or just the rears? Thanks for pioneering this, unfortunately pioneers have all the 'fun'...

[VRaptor SpeedWorks, LLC]

158094158095

One photo shows the 3 bolts that attach the hub to the knuckle. That bottom bolt by the ball joint stud is recessed. If you look at the other photo, the red lines would indicate the added thickness of the flange. The thickness is all on the inboard side which also moves the back of the wheel studs inboard. That bottom bolt already sticks way out and almost contacts the studs on the thin hubs. On the thick hubs, you end up with the end of that bottom bolt running into the wheel studs......so we ended up cutting a few threads off the ends of those bottom bolts.

[crash]

Here is the biggest advantage of the socket cap screw. It can be tightened and loosened while the lower ball joint is still attached to the upright/knuckle. If you have ever had to change one of these hubs, especially in a hurry, you know that separating the lower ball joint is a major PITA. You could probably do this with the torx, but all my torx bits are on sockets and don't fit in there. You would have to have a long shank torx to MAYBE do this without using a socket cap fastener.

[doug_porsche]

I just completed this job on the front.
Wonder why GM just didn't rotate the hub assembly 10 deg (or so) clockwise....
Then you could get to that dang bottom cap head, and the upper two cap heads, without issue.

[VRaptor SpeedWorks, LLC]

Ok....back to this project. Does anyone have a scanner or know of an app that will work with the BMW ABS unit? It has it's own OBDII plug but I'm having a tough time finding any app that will work with my ELM 327 bluetooth interface. I'm a bit concerned that as soon as I connect the battery, the MIL for the ABS comes on.....without even turning the ignition on.....

[crash]

In my experiences with working with ABS units, granted they are limited, the warning light comes on every time the system is powered. It should shut off in a short period of time under normal operating conditions after an internal systems check. When something has been done to the system, such as a sensor change out or a wiring fault has been repaired, the light will stay on until the system has a chance to calibrate itself under use. In other words, the light will stay on until all the sensors are rotating. I don't know if this can be done by hand with the car in the air. They may have to all turn relatively the same at the same time?

Before you dig too deep, I would drive it around a little with what you think is the correct setup and see if the light goes out.

[VRaptor SpeedWorks, LLC]

Thanks for the tip!! I'll give that a try. I paid $10 for an app that says it will connect to all BMW anti-lock brake units and....it won't.

[VRaptor SpeedWorks, LLC]

Ok.....That car is now finished and headed to it's owner. I test drove it for the first time yesterday and verified that the ABS does indeed work. As Crash said, once you start the car, the ABS light on the dash turns off and everything seems to work as it should. At the park where I take my photos, there are nice, flat grass areas where you can park next to the road. I got up to about 30mph and pulled off into the grass and stomped on the brake pedal and instantly got the pulsing of the ABS unit working against my foot with all of the normal ABS sounds you get when the ABS activates. Did that 3 times and then tried the same thing on asphalt.....with the same results....a short chirp from a couple tires and then the ABS kicked in and about sucks your eyeballs out of your head. That's pretty much the extent of my testing....since this is not my car and I can't go thrashing it around.

[beeman]

Great update, glad to hear you got it working. Owner HAS to be happy with the upgrade over the C5 setup.

[Shoeless]

Nice work!!!