1998 Chevy Blazer ABS Problems No Light or Codes Present

[djlacavera]

1998 Chevy Blazer ABS Engages on it own between 5 and 7 miles per hour without brake applied, and when brake is applied as well.
Brakes have been replaced front and rear to no avail.
No codes are present on scan tool nor does the light come on except for the key check, so I know it is working.
Brakes stop fine otherwise.
Is there a way without a full scan tool to isolate the problem? Would you think a wheel sensor is at fault or something with module since no codes are detected?
Thx for any help!

[MT-2500]

Originally Posted by djlacavera

1998 Chevy Blazer ABS Engages on it own between 5 and 7 miles per hour without brake applied, and when brake is applied as well.
Brakes have been replaced front and rear to no avail.
No codes are present on scan tool nor does the light come on except for the key check, so I know it is working.
Brakes stop fine otherwise.
Is there a way without a full scan tool to isolate the problem? Would you think a wheel sensor is at fault or something with module since no codes are detected?
Thx for any help!

You are right on a speed sensor fault.
But you need a ABS capable scanner to read out the wheel speed sensors and make sure they match each other.
A sensor that is just dropping out a little or not reading with the other sensors is almost impossible to catch with a volt/ohm meter.

When the problem happens there will be a code stored but you have to check for codes before you shut engine off.
ABS codes are cleared every key off and engine restart.

On some there is a problem and a TSB's with rust build up on sensors.
You could try cleaning them to see if that helps.
Also check sensor wiring and plug-ins.

[Airjer_]

The TSB repair works quite a bit. You could try that on the front hubs and if that solves the problem it was a pretty easy fix. Just make sure you very carefully remove the sensors from the hubs. Don't force them! If you break them you will be replacing the hub/bearing.

[djlacavera]

Originally Posted by MT-2500

You are right on a speed sensor fault.
But you need a ABS capable scanner to read out the wheel speed sensors and make sure they match each other.
A sensor that is just dropping out a little or not reading with the other sensors is almost impossible to catch with a volt/ohm meter.

When the problem happens there will be a code stored but you have to check for codes before you shut engine off.
ABS codes are cleared every key off and engine restart.

On some there is a problem and a TSB's with rust build up on sensors.
You could try cleaning them to see if that helps.
Also check sensor wiring and plug-ins.

TY I am going to have to pull those sensors when I have time. Appreciate your help!

[MT-2500]

You are welcome and let us know how it goes.

[old_master]

Here is a pdf of the TSB:

http://ww2.justanswer.com/uploads/Sp...527_058386.pdf