2000 Silverado ABS recalls, help ????

[jumpingjack66]

Hello guys, So, my 2000 silv with 4.8,5 speed,short bed short wheelbase, 4x4, with285/75 16 tires, and 51,000 miles, started something new recently and i need help. One or maybe both front wheels are having intermitant abs triggering probs. Once i start braking with light to moderate brake pedal and reach low speed, comming to a full stop,my front wheels or wheel( feels like passenger front wheel) triggers and cycles on dry max grip or any grip conditions. So, instead of my truck coming to a stop, it CONTINUE'S, to move forward. This abs event cycles for half to two secounds and then shuts off, and finally the truck stops. This is getting unnerving to say the least. It will trigger when all other wheels seem to have grip even in snow, so this isnt a loss of grip issue. I called the dealer today and got the usual, and I Quote" No, no recalls, is it in warranty? if not? We'll have to do some diagnostic. Might be a wheel hub problem, Cant be a wheel speed sensor problem!") His last statement is what bothered me the most. This truck has not had a brake service on front axill yet, and still has one half pads left. And no, its not under warranty, and there has never been an ABS light come on at all. Should i pay to have diagnostic done? Can i pull abs fuses ( and where are they) and see if a hub is gooffing up? I have not had any problems with abnormal wheel movement, everything runs true down the road. Money is tight, so any help would be appreciated.

Merlin, you out there?

Jack

[Sonny01]

I have the exact same problem with a 36,000 mile 2000 Silverado 5.3 automatic. I read a post where it was a rusty speed sensor causing the problem and cleaning fixed it. I have never driven anything where the brakes just start buzzing and stop working. I don't get any warning lights or Service Engine Soon. If it's a speed sensor can they just be replaced, how much are they and can I do it myself? Is there a manual that shows how to do it? I'm going to do some checking and if I turn up anything I'll let you know.
Sonny

[Sonny01]

Are you looking for GMMerlin...I heard it knows what he's doing.

[jumpingjack66]

Yes, That is who i was speaking of GMMerlin. hope he will see this. Any ways thanks for the get back and let me know what you find. It would be nice to find out it was somthing i could easily clean to fix this. Giving my dealer the truck to do unspecified diagnostic is worring. GMMerlin can get into GM data bases so his help is genuine, that and he being a GM master teck helps. Jack

[sparhawk56]

Hey guys,

I had the same problem on my 99 Silverado. I pulled out the front wheel sensors, cleaned under them, put them back in and the problem was solved. I think it has something to do with rust moving the sensor too far away from the hub. I hooked up a volt meter, measuring volts AC, while spinning the hub. You should read more than 250 mV, I was getting ~110. After cleaning them I was reading over 400 mV and the problem was gone. Hope this helps!

sparhawk56

[wagslick]

I've had similar problems with my ABS. Actually, the ABS pump is all messed up. The garage quoted me $800 for the part and $100 to put it in. I called Chevy, they say they've had plenty of people call about it but they havent issued a recall. Some one has to get their attention and let them know this is GOT to get recalled. There are just to many ABS problems on the silveradoes. I called.

[jumpingjack66]

Thanks for the get back. Is this somthing i can do with the wheel on? where is the senser? Soon as it warms up around here,( negative 5 tonight i'll attemt it i guess. Thanks, Jack

[sparhawk56]

You have to take the wheel off to get to the sensor. I believe the connection is near the top balljoint, it should be the only wire in the area. I used to have the service bulletin printed out but can't find it.

sparhawk56

[squiggs]

Myself (97 z71, 5.7L ex.cab) and my friend (01 z71 5.3L ex. cab) are both suffering the same problem, his is more pronounced with the abs pump kicking in. mine often just gives a sinking pedal feeling, ocassionaly with abs noise. I have checked the front sensors and their ohm readings are 833 & 840 (suposidly they are to be 700-1400). next step will be to try to get at the sensors and remove & clean them. perhaps the exciter ring also.
Inquired at dealer about sensors and depending on the model / year the sensor for most vehicles is an integral part of the hub assembly, according to them, a $600 cdn part. Yikes!
We shall see what happens.

[sparhawk56]

The resistance isn't the measurement you want for this. While spinning the hub by hand look at the Voltage AC. This will tell you the interaction between the exciter ring and the sensor. I believe it's supposed to be above 250 mV, mine were 100-110 before I cleaned them, over 400 after.

You can get a seperate sensor without the hub, I broke one pulling it out and had to get a new one, about $100 US.

Hope this helps!

[Gavin Curtis]

Surface rusting of the hub assembly forces the sensor away from the tone ring causing the voltage drop. This voltage drop is sufficient to cause ABS activation at low speeds; but not sufficient to trigger the ABS warning lamp.

Clean the wheel sensor, hub casting and their mating surfaces. Then reassemble.

After the repair and the ABS system has been road tested to verify proper operation; Coat the hub and sensor with several layers of rubberized undercoating spray to prevent the problem from occuring again.

[GMMerlin]

Sorry I havent been cruising the boards here lately, but from the looks of it, you are on the right path.
Here is a copy of a GM bulletin that applies to you concerns of low speed ABS activation.
Someone else mentioned the problem of the ABS pump running all the time...that is a separate issue caused by an internal failure of the ABS module....there are NO RECALLS on these issues at this time.
On the subject of the ABS pump run on, there is a gentleman on these boards..I believe his name is Ken Spragg of circuit solutions that had a fix for this...If someone can get in touch with him and have him contact me, it would be greatly appriciated.



here is the bulletin

Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface) #03-05-25-007 - (09/29/2003)
Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)
2002-2004 Cadillac Escalade, Escalade EXT

2003-2004 Cadillac Escalade ESV

1999-2004 Chevrolet Silverado

2001-2004 Chevrolet Suburban, Tahoe

2002-2004 Chevrolet Avalanche

2003-2004 Chevrolet Express

1999-2004 GMC Sierra

2001-2004 GMC Yukon, Yukon XL

2003-2004 GMC Savana

2003-2004 HUMMER H2

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 the wheel speed sensor mounting surfaces.

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual (SI Document ID #899664).
Disconnect both the front wheel speed sensor (WSS) connectors at the frame and harness.
Place a Digital Volt Meter (DVM) across the terminals of each WSS connector.
Rotate the wheel clockwise approximately one revolution per second. The minimum reading should be at least 350 ACmV's. If the reading is less than 350 ACmV's, remove the wheel speed sensor. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual. Plug the WSS bore in order to prevent debris from falling into the hub during service.
Clean the WSS mounting surface on the hub to remove any rust or corrosion using a wire brush, or equivalent.

Important
Make sure that the sensor sits flat on the hub. Check the sensor flange against a straight edge to ensure flatness. If the sensor flange is distorted, replace the sensor.


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).
Install either the original sensor or a new one in the hub. Ensure that the sensor is seated flush against the hub. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel. The voltage should now read at least 350 ACmV's.

[Gavin Curtis]

Hi GMMerlin,

I am the individual from Circuit Solutions that rebuilds the EBCM modules with the pump run condition as well as other EBCM problems. I also rebuild as the troublesome 4X4 switch cluster for the ATC equipped vehicles.

[GMMerlin]

Originally Posted by Gavin Curtis

Hi GMMerlin,

I am the individual from Circuit Solutions that rebuilds the EBCM modules with the pump run condition as well as other EBCM problems. I also rebuild as the troublesome 4X4 switch cluster for the ATC equipped vehicles.

Gavin,
I appologize for getting your name wrong..thank you for responding.
I sent you a PM.
Thanks
Merlin

[Blade615]

Thanks for the info GMMerlin. I just got finished cleanning the wheel speed sensors on my 2001 Silverado, and they work great! It's better than spending the $500 the dealership wanted me to spend. I got my info on how to do it by GMMerlin's post and the Haynes Repair Manual.
As a new member, thanks alot for the great site and posts. I am finding alot of useful info to help me.