S-10 Forum banner

1 - 20 of 40 Posts

·
Dig Or Die=I Die
Joined
·
2,022 Posts
Discussion Starter #1
My 2000 Blazer's ABS activates a little, for a split second, intermediately while lightly pressing the brakes and coming to a slow stop. Never under hard braking. (unless it's to the point where the tires are actually going to lock up.) The ABS light has come on but goes off by the time I get it to autozone to be scanned. What ever it is it isn't storing a code. When I had the PCM scanned nothing popped up.

I heard that tire pressure might cause this?? Tires don't look low but I still need to remember to get my gauge out the glove box and check the pressure to rule out the possibility. An alignment was done when I bought new tires just a few months ago. I pulled the wheels off the truck Sat. and inspected the brakes and saw nothing wrong mechanically. If tire pressure isn't it, next weekend I'll pull the front sensors out and clean them up I guess and see what that does.

BTW, there is a slight bit of play in the drivers side lower ball joint. It's been there for a few months and I never had a problem with the abs before. Could maybe the BJ be getting worse and causing the problem? I have some uppers and lower Power Performance BJs on the way since the one is bad.

My hubs are about a year old also. Of course since these stupid hubs cost a limb. I looked for the cheap ones. The pair I have on the truck are NPT brand or whatever from Advanced Auto. The bearings in one hub has already failed in after 9 months and maybe 5k miles. So maybe the sensors that come in the hubs are garbage too? I'm waiting for them to go bad so I can get some Timken hubs but don't wanna spend the $360-$400 unless I have to.

So any ideas?
 

·
Need LSx swap.....
Joined
·
4,300 Posts
autozone wont be able to scan the ABS, then can only check ECM codes (unless the one by you is different). i took my truck to a dealer that checked the codes for me, i dont remember what they were though.

i have the same issue on my 99 4wd, but im going to replace my drivers side wheel bearing before i really see whats wrong...hoping that will fix it.

ive heard bad things about the ABS units on the 99's, it may be the same one on your 98. they are the bigger units, compared to the 00+ anyway.
 

·
Dig Or Die=I Die
Joined
·
2,022 Posts
Discussion Starter #3
autozone wont be able to scan the ABS, then can only check ECM codes (unless the one by you is different). i took my truck to a dealer that checked the codes for me, i dont remember what they were though.

i have the same issue on my 99 4wd, but im going to replace my drivers side wheel bearing before i really see whats wrong...hoping that will fix it.

ive heard bad things about the ABS units on the 99's, it may be the same one on your 98. they are the bigger units, compared to the 00+ anyway.
Thanks for the reply. I suspected the cheap hand held scanners wouldn't be able to retrieve abs codes. I hope it's just dirty sensors or vibration from the driver side lower ball joint having play in it. New sensors a Rockauto.com are $65-70 each. Might as well get new Timken hubs w/the sensors for $150 each a rid my self of the POS NPT (NTP?) brand hubs I got from Advanced. One has already been replaced under warranty once from the bearing failing with in 9 months.
 

·
Registered
Joined
·
10,370 Posts
My 98 Jimmy did this and I never figured out why. I thought it was an issue with the rear brakes having sticky calipers. I replaced both calipers and rotors and pads and it still did it. Sold it to my dad and it still does it but only at like under 5mph. Any other time it's just fine. I think it's just a bad ABS unit. I seem to remember there being a recall on ABS units around mid-late 90's.
 

·
Need LSx swap.....
Joined
·
4,300 Posts
thats exactly what mine does, only from like just under 10mph to a stop. i too replaced everything in the rear, still did it. i assume its a bad abs unit, but like i said earlier i want to change my other wheel bearing to be sure.

of course, i dont think the abs module i have is repairable/rebuildable...thought i read that somewhere. i wonder if a newer unit would work? it looks like the bracket is the same, not sure about the electronics though...
 

·
Zr2.2
Joined
·
2,190 Posts
#02-05-25-006B: Antilock Brake (ABS) Activation at
Low Speeds (Clean Wheel Speed Sensor Mounting
Surface) - (Jan 5, 2006)


Subject:
Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean

Wheel Speed Sensor Mounting Surface)

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, Blazer, S10 Pickups
1995-2003 GMC Safari Van, Sonoma

1995-2001 Oldsmobile Bravada

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, ScotchBrite™, 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

Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)
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.

 

·
Dig Or Die=I Die
Joined
·
2,022 Posts
Discussion Starter #9

·
Dig Or Die=I Die
Joined
·
2,022 Posts
Discussion Starter #10
#02-05-25-006B: Antilock Brake (ABS) Activation at
Low Speeds (Clean Wheel Speed Sensor Mounting
Surface) - (Jan 5, 2006)


Subject:
Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean

Wheel Speed Sensor Mounting Surface)

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, Blazer, S10 Pickups
1995-2003 GMC Safari Van, Sonoma

1995-2001 Oldsmobile Bravada

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, ScotchBrite™, 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

Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)
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.

Thanks for this info! This is very helpful! It's kinda what I was going to do this weekend. I planned on buying a multimeter but didn't know what to set it on and what range to look for. Knowing that my problem is common and that it probably has a easy cheap fix makes me happy. :)
 

·
Need LSx swap.....
Joined
·
4,300 Posts
Like This one.
thats the same one i have also.

Thanks for this info! This is very helpful! It's kinda what I was going to do this weekend. I planned on buying a multimeter but didn't know what to set it on and what range to look for. Knowing that my problem is common and that it probably has a easy cheap fix makes me happy. :)
absolutely, this is great info...may have to have a look this weekend.
 

·
Zr2.2
Joined
·
2,190 Posts
I never checked with a multi meter on my girlfriends blazer, I just went ahead with cleaning the sensor mounting surfaces. My dad has a 99 silverado that religously the ABS acts up every couple years. He takes it to the dealer and all they do is clean it also. Might not be "common" but it's common enough.
 

·
Need LSx swap.....
Joined
·
4,300 Posts
well just having the testing parameters will help diagnose the sensor...thats easy enough.
 

·
Registered
Joined
·
10,370 Posts
Nice, now I have work to do on my now Dad's Jimmy!
 

·
GO STEELERS !!!
Joined
·
347 Posts
My 99 Blazer did this for the 1st time the other day.

Great info!

I'm glad it's a simply fix and not a butt load of $$$$$$$! :D
 

·
Zr2.2
Joined
·
2,190 Posts
I haven't found a place that sells just a new sensor for the front hubs, so I suppose if the sensor is bad it could cost a "butt load" of money as you'd be looking at a new hub(s).
 

·
Need LSx swap.....
Joined
·
4,300 Posts
I haven't found a place that sells just a new sensor for the front hubs, so I suppose if the sensor is bad it could cost a "butt load" of money as you'd be looking at a new hub(s).
rockauto has them, about $50 each for my 99 4x4
 

·
Zr2.2
Joined
·
2,190 Posts

·
Dig Or Die=I Die
Joined
·
2,022 Posts
Discussion Starter #20
I mentioned sensors from rockauto in post #2. :p

My ABS hasn't acted up all week since I pulled the wheels off, inspected the brakes, sucked some of the old brake fluid out the reservoir and put some new fluid in. So until it starts acting up again, I ain't messing with it. That is unless I get bored or something. I did by myself a digital multimeter. I'm not sure where to set the dial at to test them though.
 
1 - 20 of 40 Posts
Top