Question re: 2000 GMC Sierra ABS brakes

[QuickWrench]

2000 GMC Sierra 2500 Ext. Cab 4x4, 6.0L V8, 4L80 Auto, new body style...

When slowing down, the ABS unit always kicks in right around 6MPH. It's far more noticable when slowing down gradually, since you're at 6MPH longer. It's a huge aggravation, and I nearly hit a parked car yesterday, since the wheels continue to rotate (obviously) when the ABS kicks in.

There are no other problems whatsoever with the truck. It's run like a top since new.

Thoughts? Wheel speed sensor(s)? ECM?

Thanks in advance,

 

[gn85]

I'm assuming it hasn't flashed a code... it may have a code stored.

 

[QuickWrench]

Nope, no codes.

 

[LC2 ROD]

Sounds like a wheel speed sensor is droping out.

 

[pwrdbypsi]

I had a truck at work that did the same thing. The E.B.C.M had an internal failure and would not register from one of the wheel sensors under 7 mph. It would think the wheel was locked up and activate the abs system. Hope this helps

 

[TURBOSKI]

Actually the low speed abs activation is a well know problem on the Silverado trucks especially in the rust belt. It is well talked about on the truck websites and I do believe there is a GM service bulletin on this problem. It stems from corrosion on the front hub where the abs sensor picks up a false signal due to reduced air gap. The hub can be cleaned up and around the sensor to restore proper clearences. As with anything nothing lasts forever as my truck has had this maintenance performed twice (about 2 years apart) by the dealer. Worked very well after the maintenance. Hope this helps.

 

[QuickWrench]

Actually the low speed abs activation is a well know problem on the Silverado trucks especially in the rust belt. It is well talked about on the truck websites and I do believe there is a GM service bulletin on this problem. It stems from corrosion on the front hub where the abs sensor picks up a false signal due to reduced air gap. The hub can be cleaned up and around the sensor to restore proper clearences. As with anything nothing lasts forever as my truck has had this maintenance performed twice (about 2 years apart) by the dealer. Worked very well after the maintenance. Hope this helps.

This sounds like the ticket. The truck spent its first 4 years in Ohio. I figured as much...just haven't had much time to dig into the truck lately, with the summer race schedule. I'll look up the TSB for it.

Thanks a lot, guys.

 

[TURBOSKI]

The quick fix but temporary is to pull the 60amp ABS fuse under the hood. The ABS and brake light will come on the dash, but you will beable to safely stop without the the false ABS activation while turning into a parking space or with me almost going through a garage door as you trying to stop. Hope this will workout for you.