Help Bleeding ABS using XTOOL Anyscan A30M V2.0 scan tool software

[GreenBravada]

I replaced the master cylinder on my 2002 Bravada and bled the brakes in the traditional way. Now I have that low speed buzz when stopping, and I think there might be air in the ABS module. I have a new XTOOL Anyscan A30M V2.0 scan tool with very comprehensive software. For my 2000 Buick LeSabre, the scanner's specialty program for bleeding the ABS module lead you through the procedure step by step (push on the pedal, open right front bleeder, etc). The program for the Trailbazer/Envoy/Bravada is also present, but when you run it there are no directions at all about bleeding the lines. It just tells you to step on the brake, buzzes the ABS, tells you to step on the pedal again, buzzes again. No instructions to open a bleeder.

Has anyone dealt with this? It's pretty common software used in all the XTOOL scanners.

I have no codes being thrown by the brake system. I can clean and/or replace the speed sensors at each wheel, but this buzz seems to have resulted directly from installing the master cylinder (which I did bench bleed).

 

[mrrsm]

You might be dealing with a separate issue involving "Rust Jacking" the Plastic Tip of either one or both of your ABS Sensors becoming slightly elevated above the Reluctor Tone Ring inside of the Wheel Hubs and causing the ABS Sensor to activate improperly. THIS is the Signature Video in how to use a DMM to unplug the ABS Sensor and take A/C Voltage Readings while spinning the Front Wheels and searching for a 450 Milli-Volts in Response. Anything less means that the Sensor Tip is too far above the Tome Ring. These Repair Instructions are edifying... and superb.

It is important to understand that it is the Action of the Spinning Wheel which generates the Mild A/C Sine Wave Voltage that gets picked up by the ABS Computer-Module and uses that Signal to decide whether or not to activate the Low Speed ABS Vibration-Warning and prevents the Front Wheels from Locking up on Slippery Roads with "Black Ice"or in the presence of deep enough water on the road to cause dangerous Hydro-Planing while at speed:

LISTEN to EVERYTHING this Dude says... If the Internals of the Wheel Hubs are worn out...this can cause the Tone Rings to displace enough to cause the ABS Problem.

 

[GreenBravada]

Thanks very much, mrrsm. That's a lot of good information. I guess my post had two parts. One is the low speed vibration, and the other is how to use the XTOOL software for this vehicle group. I thought (and still think) someone might have had experience with the software and might offer some advice.

I'm aware of the rust jacking business. I have cleaned a lot of rust scale from underneath this vehicle, and it's very likely that that's pat of the problem and maybe the whole problem. When I was bleeding the brakes, I noticed that the sensors on both front wheels were not installed carefully and the wires were flopping around. One had been dragging against the disc or something (can't recall) and had been worn through the plastic insulation to where the shielding was visible. I have new sensors on hand, and I will probably remove the current ones, thoroughly clean the attachment point including the shim if it is there and the ring, and install the new sensors. That's all pretty straightforward and may eliminate the buzz at low speed symptom.

You mentioned the Low Speed ABS Vibration-Warning. Is that just the general ABS feedback through the pedal, or is that a specific thing that happens only at low speed in certain situations? Does it indicate a malfunction when it's working properly, or is it an actual warning to the driver? I can understand it being triggered erroneously if a sensor signal is weak and tricking the computer into thinking conditions are present when they are not.

Anyway, thanks so much for your assistance. I'll start with replacing those sensors.

Excellent video and all stuff that should be done anyway on a car like mine that has had "deferred" maintenance. I have electronics training and a good multimeter. I can check the old ones and the new ones. I have experience with this type of sensor in other applications and know that spacing and cleanliness make a big difference.

Thanks again.

 

[mrrsm]

THAT is both a WARNING and an ACTION being done by the ABS Unit Clamping and Releasing the Brakes RAPIDLY enough to prevent the Front Wheels from completely locking up and leaving the Driver with absolutely No Way to STEER the vehicle...whether on Ice, Snow or when Hydro-Planing.

I know you'll want to take a swing at my chin for asking... But on your Year 2000 Vehicle...have the Hubs ever been R&R'd... ? The canting and Strange Wear of the Disk to Pads, etc. can originate with loose and worn Internal Hub Bearings as well. Sometimes...just changing out the Sensors can be like, "Putting a Fifty Dollar Saddle... On a Two Dollar Horse..." :>)

 

[GreenBravada]

THAT is both a WARNING and an ACTION being done by the ABS Unit Clamping and Releasing the Brakes RAPIDLY enough to prevent the Front Wheels from completely locking up and leaving the Driver with absolutely No Way to STEER the vehicle...whether on Ice, Snow or when Hydro-Planing.

I know you'll want to take a swing at my chin for asking... But on your Year 2000 Vehicle...have the Hubs ever been R&R'd... ? The canting and Strange Wear of the Disk to Pads, etc. can originate with loose and worn Internal Hub Bearings as well. Sometimes...just changing out the Sensors can be like, "Putting a Fifty Dollar Saddle... On a Two Dollar Horse..." :>)

Well, it's a 2003 Bravada that just passed 120k miles, and all of the brake components look fine. I understand completely what ABS is about. Have had it since 1993 when my brand new Volvo 940 wouldn't stop on glare ice going slightly downhill because the brakes continuously released. Ten miles an hour is still not stopped. And I understand about the steering under braking IF you have a place to steer to that's not occupied by another car.. ;-)

Also read about replacing the hubs elsewhere. I'm going to redo the entire front end pretty soon, but just want to see if replacing the sensors will fix this. I'll look at the hubs then when I have that all apart. Remember, I had no symptoms at all until I bled the brakes and moved those sensor wires.

Appreciate your response and your help!

 

[GreenBravada]

"De Mortuis GMT-360... Nil Nisi Bonum..."
(NEVER Speak Ill... of a Dead GMT-360)

I had four (count 'em : 4) years of Latin in high school. I told my sons to take Latin, but also told them two years is plenty. One of them took four years, anyway. Then he majored in Philosophy in college.

 

[budwich]

does your xtool provide live data reading. IF so, there are data pids for the speed sensor from each hub. You can check those to see if there is something "different" between the hubs being reported. It costs nothing to do the check if you have the tool capability.

 

[GreenBravada]

Thanks, Budwich. I'm still learning the software, but I was just able to use the live data to troubleshoot a misfire in my Buick right down to the spark plug where the issue was. I'll try that with the Bravada, but I need to finish the Buick first. I'll report back when I get to it. Good suggestion. Thanks very much.

 

[Mooseman]

For the ABS bleeding, the tool fails to explain the remainder of the procedure (11-13). This is what I got from Charm.li

ABS Automated Bleed Procedure​

ABS Automated Bleed Procedure

Two - Person Procedure

Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

Caution: Refer to Brake Dust Caution in Cautions and Notices.

Important:
^ Use the two-person bleed procedure under the following conditions.
- Installing a new Electro-Hydraulic Control Unit (EHCU) or new Brake Pressure Modulator Valve (BPMV).
- Air is trapped in the valve body.
^ Do not drive the vehicle until the brake pedal feels firm.
^ Do not reuse brake fluid that is used during bleeding.
^ Use the vacuum, the pressure and the gravity bleeding procedures only for base brake bleeding.

1. Raise the vehicle in order to access the system bleed screws.
. Bleed the system at the right rear wheel first.
3. Install a clear hose on the bleed screw.
4. Immerse the opposite end of the hose into a container partially tilled with clean DOT 3 brake fluid.
5. Open the bleed screw 1/2 to 1 full turn.
6. Slowly depress the brake pedal. While the pedal is depressed to its full extent, tighten the bleed screw.
7. Release the brake pedal and wait 10-15 seconds for the master cylinder pistons to return to the home position.
8. Repeat the previous steps for the remaining wheels. The brake fluid which is present at each bleed screw should be clean and free of air.
9. This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every four to six strokes of the brake pedal in order to avoid running the system dry.
10. Press the brake pedal firmly and run the Scan Tool Automated Bleed Procedure. Release the brake pedal between each test.
11. Bleed all four wheels again using Steps 3-9. This will remove the remaining air from the brake system.
12. Evaluate the feel of the brake pedal before attempting to drive the vehicle.
13. Bleed the system as many times as necessary in order to obtain the appropriate feel of the pedal.

After it's properly bled, if you're getting unwanted ABS activation at low speed, it's either a rust jacked wheel sensor or a wheel hub is going bad. Use your scan tool to see at which wheel is dropping out when coming to a stop. That would be your bad sensor/hub. A bad hub is the usual problem. I'm currently getting this with a NEW hub from Mevotech but when slowing down with the wheels turned, like in a highway off-ramp.

 

[GreenBravada]

For the ABS bleeding, the tool fails to explain the remainder of the procedure (11-13). This is what I got from Charm.li



After it's properly bled, if you're getting unwanted ABS activation at low speed, it's either a rust jacked wheel sensor or a wheel hub is going bad. Use your scan tool to see at which wheel is dropping out when coming to a stop. That would be your bad sensor/hub. A bad hub is the usual problem. I'm currently getting this with a NEW hub from Mevotech but when slowing down with the wheels turned, like in a highway off-ramp.

That's the procedure that comes up when you run the ABS bleed software routine. It tells you to press the pedal, it buzzes, and it tells you to press the pedal, and it buzzes and you do this multiple times without ever bleeding during the test. How can air move out of the system if you never open the bleeders?

In the Buick LeSabre routine, it tells you which bleeder to open, then it buzzes and tells you to close the bleeder until you've done all four wheels. That procedure certainly makes more sense.

When I got the vehicle, the brake fluid was a dark green and the inside of the reservoir had green scum in it. I tried to do a typical flush but could net get the master cylinder and reservoir completely clean. In fact, the master cylinder on the truck was manufactured so that it could not be disassembled to be clean. No snap ring. I replaced the master cylinder and added fresh brake fluid and flushed until it came out clean. No indication that there was any air left in the system, but then I started getting the ABS buzz for a second as I came to a complete stop.

I appreciate the information, Mooseman and will hold onto it. I think I will be checking the ABS sensors, especially the one with damaged insulation.

How would you check the hubs? Are we basically talking about bad wheel bearings inside the hub assemblies?

 

[mrrsm]

This Thread covers another universal approach to Bleeding Brakes that voids the need to become a "One Man Band" in the process and all but guarantees a Best Of All Outcomes:

Thread 'How to Perform a Pressurized Brake Bleed on ANY GM Vehicle'

Jan 25, 2020

I thought it would be a good idea to break out this “Pressurized Brake Bleeding Procedure” from the other Brake Repair Work involved with my 2000 Chevrolet Silverado 1500 Long Bed Truck. I think this Procedure stands out from all others because it is THE Fastest, THE Easiest and THE Most Efficacious Method to Bleed the Brakes on ANY Vehicle… AND NOT SPILL A DROP OF OLD OR NEW BRAKE FLUID.

If my attempt at a Write Up is evaluated as being either too Common or Redundant to other contemporary procedures … Please just delete it:

The Pictorial View of these Text Instructions:...

• mrrsm
• Replies: 1
• Forum: Article Submissions

• 

 

[Mooseman]

I think what happens if that the ABS bleed sends any air into the lines, which is why you have to re-bleed each wheel after the procedure, and you have to repeat until all air is out and you get a firm pedal.

Don't get overly concerned if it feels a bit on the soft side compared to older vehicles. I thought my 02 TB had problems with a soft-ish pedal so I bled it to death, replaced the master cylinder, bled even more, and then had the dealer bleed the ABS because this was before I got a Tech 2. The pedal was the same. If it doesn't go down to the floor and it brakes well, it's fine.

 

[budwich]

How would you check the hubs? Are we basically talking about bad wheel bearings inside the hub assemblies?

There isn't much to check. If you look at the sensor data (voltge) that decision to active ABS is made from, especially at slow speeds, you may find a "slight difference" between sensors. It could be caused by contamination within the hub itself (on the "tone ring"... dirt / steel / iron rust coming from bearing wear). I am not sure you could readily determine the "wear" part as opposed to the "dirt". The sensor, itself, maybe "tired" / changed in its "induction pickup" function. It can be replaced but most would just replace the whole hub.
Based on my limited experience and success using the "live sensor data", the low speed activation was quickly fixed.

I would surmise that if you aren't getting ABS activation "at speed" versus "slow speed", then the issue isn't a ABS / fluid / air issue but a hub / sensor issue.

 

[GreenBravada]

I think what happens if that the ABS bleed sends any air into the lines, which is why you have to re-bleed each wheel after the procedure, and you have to repeat until all air is out and you get a firm pedal.

Don't get overly concerned if it feels a bit on the soft side compared to older vehicles. I thought my 02 TB had problems with a soft-ish pedal so I bled it to death, replaced the master cylinder, bled even more, and then had the dealer bleed the ABS because this was before I got a Tech 2. The pedal was the same. If it doesn't go down to the floor and it brakes well, it's fine.

I bled the heck out of it to get rid of that contaminated fluid. I read somewhere that the green color is copper contamination. Wouldn't be surprised if there was a bit of air somewhere in the ABS module. At this point, I think the wheel sensors and ring are the thing to check, especially since I can tell they were replaced rather unprofessionally and might not even be the exact factory equivalent. When I saw one was damaged, I ordered a pair, so I have them.

I have five cars on my little residential property, and there's always a triage list where one car takes precedence over the others, so the Bravada won't be in the garage for a couple of days at least.

Brakes have always felt fine and look to be one of the areas that had recent attention. Just that buzz the last half second as your stop at a stop sign. Not a safety issue, but annoying. Cleaning up those sensor mounts and checking the rings are the kind of thing people like us would do at least once but wouldn't be done in a routine brake job in a tire store.

Thanks again!

 

[budwich]

Not a safety issue, but annoying

Might not be an "immediate" safety issue... but depending on how often the ABS is activating, it could potential cause a pump issue which might be a $$$ issue.... maybe.

 

[GreenBravada]

Might not be an "immediate" safety issue... but depending on how often the ABS is activating, it could potential cause a pump issue which might be a $$$ issue.... maybe.

How do you know your ABS is working if it doesn't buzz once in a while?

;-)

Don't worry. I'll be taking care of it and not currently driving the Bravada.

 

[budwich]

Once in while is different than every time, your vehicle slows down to zero especially in city driving. Mine would do the "chatter" almost every time heading into a stop which was pretty often around town.

 

[GreenBravada]

Once in while is different than every time, your vehicle slows down to zero especially in city driving. Mine would do the "chatter" almost every time heading into a stop which was pretty often around town.

Stops just fine even in an emergency, but it shouldn't do that. I'm sure it's a fixable thing. Right now I have a Buick LeSabre apart in my garage. Driving the 1993 Volvo 940 Turbo Wagon.

 

[Mooseman]

I remember when my '02 would do it I would sail right through stop signs. Scary AF. I wound up pulling the ABS fuse until I replaced the hub. Later years they added a fault code for it and would turn off ABS when it detected it a couple of times. My '07 did that once telling me a hub was bad.

 

[GreenBravada]

I remember when my '02 would do it I would sail right through stop signs. Scary AF. I wound up pulling the ABS fuse until I replaced the hub. Later years they added a fault code for it and would turn off ABS when it detected it a couple of times. My '07 did that once telling me a hub was bad.

Mine is just a slight buzz JUST as you come to a complete stop. Right now, I am changing the rear plugs and valve cover gasket on my 3800 V6 Buick LeSabre. Quite an operation with a lot of disassembly, and I hope I can remember how to put it all back together! I have a piece of plywood forming a platform on top of the engine in order to get back there. My old bones are complaining. ;-)

 

[GreenBravada]

I replaced the master cylinder on my 2002 Bravada and bled the brakes in the traditional way. Now I have that low speed buzz when stopping, and I think there might be air in the ABS module. I have a new XTOOL Anyscan A30M V2.0 scan tool with very comprehensive software. For my 2000 Buick LeSabre, the scanner's specialty program for bleeding the ABS module lead you through the procedure step by step (push on the pedal, open right front bleeder, etc). The program for the Trailbazer/Envoy/Bravada is also present, but when you run it there are no directions at all about bleeding the lines. It just tells you to step on the brake, buzzes the ABS, tells you to step on the pedal again, buzzes again. No instructions to open a bleeder.

Has anyone dealt with this? It's pretty common software used in all the XTOOL scanners.

I have no codes being thrown by the brake system. I can clean and/or replace the speed sensors at each wheel, but this buzz seems to have resulted directly from installing the master cylinder (which I did bench bleed).

Here is a online manual that is similar (probably identical) to the XTool procedure for my 2000 Buick LeSabre. Note the specific instructions about opening the bleeder and pushing the brake pedal.

Xtool D7S Manual

Xtool D7S User Manual View and Read online. Est. reading time 27 minutes. D7S Diagnostic Equipment manuals and instructions online. Download Xtool D7S PDF manual.

www.manualslib.com

For the 2003 Trailblazer/Bravada/Envoy ABS bleed software, there are NO instructions about opening bleeders.

 

[mrrsm]

The probable reason is that the ABS *Purging* Actuation being done electronically within the scope of what the XTool or other High End Scanner can perform under controlled conditions (Pressing HARD on the Brake Pedal) and remove Air Bubbles and Condensation in the Hygroscopic Brake Fluid... just from the ABS "Innards" and sort of "sends it on down the line" where the other Regular Brake Bleed Maintenance is expected to be covered and dealt with via the GM Shop Manual Instructions.

The ABS can be done independently without the follow on Four Wheel Brake Bleed Procedure ... and many Owners may not realize that the A/C Wheel Hub Sensors "Rust Jacking" elevation can be the start of the entire issue.

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Learn what is the correct order to bleed the brakes and how to bleed them yourself with these tips from our expert mechanics on the 1A Auto blog

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