HOW I DISABLED my ABS (1995 SAFARI AWD)

[webcat]

If you wanted the abs light to go out i wonder if you could just take the light bulb out or would that cause some other problems?

[CDGsafari98]

these awd vans are all awd drive they did not make a 4wd version. I have seen a post or two suggesting how to make them 4wd however. Sounds interesting!

[d0n]

Did anyone figure out what the real problem is with the ABS system coming on at every stop?

My 2000 safari AWD just started doing the same damn thing and I almost rear ended a few people.

My ABS light was on so I installed a new front right sensor ($60 from ebay). The ABS light went out but now my ABS system is acting all weird and coming on everytime I stop. It's VERY DANGEROUS! I have to assume that since the ABS light is no longer on, my other sensor/s are ok? I don't want to buy and install another $60 sensor if I don't have to. But... what else could it be?

[timelessbeing]

It IS very dangerous. I think someone else on this forum almost crashed into a building because of it. I know I've had some close calls. The problem is caused by rust between the wheel speed sensor and the reluctor ring. If you search the forum there should be the TSB posted about it, or your dealer might be able to print it for you.

My bearings wore out a little while ago so I had to replace the whole hub ($550!! The mechanic said it's the most expensive he's ever seen) which contains the sensor assembly, and now the problem is gone.

[gwd]

My ABS also failed. I changed my sensors but it also got worse. I believe my ABS computer under the driver seat underneath the van is defective. I have a link which I am going to try.
http://modulemaster.com/en/index.php

They fix the the computer for the ABS systems.

[timelessbeing]

You can replace the sensor as many times as you want and it won't fix the problem.
You have to clean the reluctor ring, and then test the sensor reading to make sure it's within spec. Or replace the whole hub.

[d0n]

You can replace the sensor as many times as you want and it won't fix the problem.
You have to clean the reluctor ring, and then test the sensor reading to make sure it's within spec. Or replace the whole hub.

How do I clean the reluctor ring? Can i blow brake kleen & compressed air into the sensor hole or is the cleaning procedure more involved than that?

When I installed my new sensor, I didn't do anything except for pull the old one out and stick the new one in. I guess I should have cleaned in the hole!

Can anyone post he TSB on this issue?

[timelessbeing]

Subject: Antilock Brake (ABS) Activation at Low Speeds (Clean Wheel Speed Sensor Mounting Surface) #02-05-25-006B - (01/05/2006)

Models: 1999-2000 Cadillac Escalade

1995-1999 Chevrolet Silverado (Old Style)

1995-2000 Chevrolet Suburban, Tahoe (Old Style)

1995-2003 Chevrolet Astro Van, Blazer, S10

1995-1999 GMC Sierra (Old Style)

1995-2000 GMC Yukon, Yukon XL (Old Style)

1995-2001 GMC Envoy, Jimmy

1995-2003 GMC Safari Van, Sonoma

1995-2001 Oldsmobile Bravada

This bulletin is being revised to update the correction and warranty information. Please discard Corporate Bulletin Number 02-05-25-006A (Section 05 -- Brakes).


Condition

Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause

The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction

Measure AC voltage and clean wheel speed sensor mounting surfaces.
1. Raise the vehicle on a hoist.
2. Disconnect both the front wheel speed sensor harness connectors.
3. Place a DVM across the terminals of each sensor connector.
4. Rotate the wheel with hand speed and measure the ACmV's. The reading should be at least 350 ACmV's.
5. If the reading is between 200 and 350 ACmV's, remove the wheel, caliper and rotor in order to gain access to the speed sensor.
6. Remove the wheel speed sensor and plug the hole to prevent debris from falling into the hub during service.
7. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, ScotchBriteTM, or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.
8. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.
9. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (Canadian P/N 89022218).
10. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor O-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (Canadian P/N 993037).
11. Install either the original sensor or a new one in the hub and secure the sensor. Ensure that the sensor is seated flush against the hub.
12. Install the rotor, the caliper and the wheel.
13. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel by hand. The voltage should now read at least 350 ACmV's.

Parts Information


Part Number Description
89022217
(Canadian P/N 89022218)
(Package of 2 cans) Rust Penetrating Lubricant
(Each can will service 50+ vehicles)
01051344
(Canadian P/N 993037)
(Package of 12 tubs) Wheel Bearing Lubrication - Tub
(Each tub will service 25+ vehicles)
Place unused material on dealer shelf for future use.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Description Labor Time
H9714* Front Wheel Speed Sensor Inspect and Clean (Both Sides) 1.2 hrs
* This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.

[d0n]

[Bis]

My ABS also failed. I changed my sensors but it also got worse. I believe my ABS computer under the driver seat underneath the van is defective. I have a link which I am going to try.
http://modulemaster.com/en/index.php

They fix the the computer for the ABS systems.

I think this may be my last option to fixing my issue. I looked at this page which troubleshoots the exact problem I am having:
http://modulemaster.com/en/wizard/kh_32 ... causes.php

My mechanic says that corrosion in not an issue and the 50A fuse is fine. So what I am left with is a potentially faulty module (soldering and/or other electronic parts going bad inside the module) due to heat/cold and vibration (according to service rep that took my call).

It can be sent in as long as it looks like this:

http://modulemaster.com/en/abs/kh325_310_30.php



2001 was made with a choice of 3 different units? Anybody know for sure?

[Bis]

When I would get to around 8 or 9 mph when braking, the ABS would act strange and not brake correctly, almost rear ended someone .

I was about to post a whole new thread about this, but then saw this and thought I'd try to get some feedback from you guys.
When I purchased the van a few months back the ABS/Brake lights would come on when the car vibrated. A mechanic tried pretty much everything to try to stop the problem but the problem with the lights on the dashboard still occurred.
At the same time I noticed that from time to time the brakes would "lose power" (the pedal would sink slightly and no braking would take place, almost causing an accident at the same spot on the road several times). I realized that every time the brakes "failed" I was going over a railroad track and braking at the same time. To this day I am not sure why that happened, but one thing I did find was the cause of the lights on my dashboard coming on: I did more research and found out that it is a common problem for the ABS module to go bad. At the same time I thought that maybe the ABS module was causing the brakes to act up when I went over the tracks for whatever reason. Needless to say I sent the module to get fixed, by the time I got to putting it back on the car 2 months had gone by and I had forgotten about the braking problem that would take place by the RR Tracks. That is until this week when the ABS module finally went back on!

The lights on my dashboard don't come on anymore, so that is fixed, but the BRAKING problem re-appeared once again (one time only). Am I to think that the ABS system is failing somehow? Even after a new module and a full brake inspection took place? The sensors were cleaned and everything...!!!

I am dumbfounded and worried. Winter is coming and I have heard some horror stories about Astro/Safari ABS brakes. I am scared the brake problem will happen at higher speeds or in a critical moment.

Any feedback is appreciated.

[Phantom]

Since the ABS is a computer interactive device , to get a full diagnosis of the ABS functionality , a OBD2 ABS diagnostic program will need to be run to determine the full status of operation , it can be as simple as a code that has been logged and need to be cleared , but a diag program has to be run to see it as it is an independent system that ties into the OBD , I have some pdf files on it , I'll try to dig them up for more info

If you have worries you can pull the ABS fuse which will disable ABS and revert back to only your regular braking system until you find a more permanent answer/solution

[Bis]

Since the ABS is a computer interactive device , to get a full diagnosis of the ABS functionality , a OBD2 ABS diagnostic program will need to be run to determine the full status of operation , it can be as simple as a code that has been logged and need to be cleared , but a diag program has to be run to see it as it is an independent system that ties into the OBD , I have some pdf files on it , I'll try to dig them up for more info

If you have worries you can pull the ABS fuse which will disable ABS and revert back to only your regular braking system until you find a more permanent answer/solution

If I experience it once more I will have to do that. Can't trust it.

[WoodButcher]

If I experience it once more I will have to do that. Can't trust it.

I don't trust ABS period. I rear ended someone while driving a brand new 1993 Chevy 1/2 ton van. It was wet, I put my foot to the floor and that thing chugged right into the car in front of me. There was no place to steer to avoid collision but I absolutely believe I could have stopped with normal brakes without loosing control. Maybe ABS got better, I don't know but when one wheel started to lock they all released and started the ABS chug. If the ABS let go that one tire only, it may have worked. Since then I disable all mine. ABS is good for the person who is likely to panic and put their foot to the floor.

[Phantom]

ABS is good for the person who is likely to panic and put their foot to the floor.

Unfortunately that be a whole lot of people , like those so engaged in cell phone conversations or texting while driving that they are not paying attention to their driving and only notice an emergency situation when they only have 20 feet to stop and don't have room to manually gradually pump the brakes and just slam on the pedal ......which is also a reason to have them serviced and tested for proper operation

[Bis]

When I would get to around 8 or 9 mph when braking, the ABS would act strange and not brake correctly, almost rear ended someone .

I was about to post a whole new thread about this, but then saw this and thought I'd try to get some feedback from you guys.
When I purchased the van a few months back the ABS/Brake lights would come on when the car vibrated. A mechanic tried pretty much everything to try to stop the problem but the problem with the lights on the dashboard still occurred.
At the same time I noticed that from time to time the brakes would "lose power" (the pedal would sink slightly and no braking would take place, almost causing an accident at the same spot on the road several times). I realized that every time the brakes "failed" I was going over a railroad track and braking at the same time. To this day I am not sure why that happened, but one thing I did find was the cause of the lights on my dashboard coming on: I did more research and found out that it is a common problem for the ABS module to go bad. At the same time I thought that maybe the ABS module was causing the brakes to act up when I went over the tracks for whatever reason. Needless to say I sent the module to get fixed, by the time I got to putting it back on the car 2 months had gone by and I had forgotten about the braking problem that would take place by the RR Tracks. That is until this week when the ABS module finally went back on!

The lights on my dashboard don't come on anymore, so that is fixed, but the BRAKING problem re-appeared once again (one time only). Am I to think that the ABS system is failing somehow? Even after a new module and a full brake inspection took place? The sensors were cleaned and everything...!!!

I am dumbfounded and worried. Winter is coming and I have heard some horror stories about Astro/Safari ABS brakes. I am scared the brake problem will happen at higher speeds or in a critical moment.

Any feedback is appreciated.

So I am back with a solid review of the problem, maybe you guys can relate in some way or give me any other clues you might feel are helpful:

For some reason it is only when braking WHILE THE VEHICLE IS DRIVING OVER BUMPS OR ROUGH TERRAIN that the ABS act up.
It is a consistent reaction to the bumps on the road which for some reason gets the ABS motor going (I can hear it when it comes on), and creates a situation where the pedal sinks further and further and the braking action is lost. You feel like you have lost your brakes completely and as soon as you get over the bumps you feel the pedal re-gaining pressure and braking goes back to normal.

It happens EVERY TIME now when I come to this one corner which has a set of rail road tracks right as you approach the stop sign. Driving 35MPH towards the stop sign you start to slow down as you hit the tracks, hitting the bumpy tracks at maybe 25 or 20MPH with the brakes on. THis is when the ABS motor comes on (pretty loud) and no reason for ABS to engage since the breaking force is not very large and no wheels are "slipping".

I am clueless about this and wonder what the hell the problem could be? Could the wheel sensors be affected by the vibration somehow? I would find that hard to believe.
I will try to get an OBD2 ABS diagnostic ASAP.

[chevymaher]

Take your wheels and brakes off including rotors.Spray the back of the rotors and the sensors with brake cleaner.Metal shavings and brake dust from the brakes gather there and confuse the reading causing false readings setting it off.Personally I dont like them but that how you care for them.I actually going back to the scene of my accident last year and hit the brakes at the point of impact at the same speed I was traveling and I bet on dry pavement I stop before I did in the accident.And I laid on the brakes 30 feet before impact.My brother and I were arguing about dry ground with them yesterday.I am taking the challenge.No way that van takes a length of a football field to stop from 30 mph especially after hitting a car which slowed it down.Brakes locked and stopped working.

[Bis]

I will find the report I saw from another Astro/Safari owner on pretty much the same scenario that you mentioned. It worries me, a lot.
By the way, the sensors on that van were cleaned right after I got it, so something like 4 months ago? Do you think they need cleaning again?

[Phantom]

It would not seem that you would need them cleaned so soon , but some softer versions of brake pads create more dust than others, so it is possible ,, you may have a wire that has been damaged or has a weak electrical connection , or there may be a weak bad electrical connection at the ABS motor , as corrosion can set in , try cleaning all electrical connecters , you may have to have a ABS diagnostic scan performed , but make sure all the connections are clean and tight before you do , read up on ABS and ABS diagnostics so when you have it tested you'll know what they are talking about ,,sometimes techs will just assume the ABS motor/module is bad and say that is the problem ,, it may be , then maybe not , with it costing as they do it be better to know for sure .

[Bis]

http://townhall-talk.edmunds.com/direct ... d/76#MSG76

Thanks for your concern.... For your records, there's a known problem with the ABS system on the Astro/Safari vans. There's an official TSB but NO recall. Still amazes me why no formal recall. For details....

Bottom line is... Defector sensor (which needs to be replaced) or the existing sensor is too "rusted up" to work properly...

-----------------

.... Basically, dirty sensor mounting surfaces cause the signal to drop out at low speeds, which fools the ABS system into thinking that it is experiencing an ABS event when it's not.

Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor
Mounting Surface) #02-05-25-006A - (11/26/2002)
Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor
Mounting Surface)
1999-2000 Cadillac Escalade

1995-1999 Chevrolet Silverado (Old Style)

1995-2000 Chevrolet Suburban, Tahoe (Old Style)

1995-2003 Chevrolet Astro Van, Blazer, S10

1995-1999 GMC Sierra (Old Style)

1995-2000 GMC Yukon, Yukon XL (Old Style)

1995-2001 GMC Envoy, Jimmy

1995-2003 GMC Safari Van, Sonoma

1995-2001 Oldsmobile Bravada

This bulletin is being revised to change model information. Please discard
Corporate Bulletin Number 02-05-25-006 (Section 05 -- Brakes).

Condition
Some customers may comment on ABS activation at low speeds, usually below 8
km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause
The cause of this condition may be an increased air gap between the wheel
speed sensor and the hub reluctor ring due to rust and debris built up on
the sensor mounting surface.

Correction
Measure AC voltage and clean wheel speed sensor mounting surfaces.

1.. Raise the vehicle on a hoist.
2.. Disconnect both the front wheel speed sensor harness connectors.
3.. Place a DVM across the terminals of each sensor connector.
4.. Rotate the wheel with hand speed and measure the ACmV's. The reading
should be at least 350 ACmV's.
5.. If the reading is between 200 and 350 ACmV's, remove the wheel,
caliper and rotor in order to gain access to the speed sensor.
6.. Remove the wheel speed sensor and plug the hole to prevent debris from
falling into the hub during service.
7.. Clean the speed sensor mounting surface on the hub to remove rust and
corrosion.

Important
Make sure that the sensor sits flat on the hub. If the sensor flange is
distorted, replace the sensor.

8.. Apply a thin layer of bearing grease to the hub surface prior to
sensor installation.
9.. Install either the original sensor or a new one in the hub and secure
the sensor. Ensure that the sensor is seated flush against the hub.
10.. Install the rotor, the caliper and the wheel.
11.. Place the DVM across the sensor terminals and recheck the voltage
while rotating the wheel by hand. The voltage should now read at least 350
ACmV's.