Hey guys,

I am looking for some help. I have a 2000 4wd blazer and am having ABS issues. I start the truck and begin to drive off and the brakes make a funny whining noise and they momentarily do not work. Then the ABS light comes on and I have brakes. This happens every time I turn off the truck. When I restart it, the process repeats itself. It has been doing this for quite some time. Does anyone have any ideas on what might be causing this? Any help would be greatly appreciated.

 

Any suggestions?

 

Get the ABS codes read (a generic OBD2 scan tool cannot access the ABS system) and let us know what they are.

 

If I had to guess I would say It's the speed sensor on the right front wheel. I have replaced mine twice now with similar symptoms. If you live somewhere that gets snow/ice it builds up around the wheel and it can I either loosen or cut the wire for the sensor. If it is indeed the speed sensor make sure you replace it with one that comes with a protective guard. Or you can replace it twice like I did, two winters in a row.

 

Where can you get the ABS codes read? Does it cost anything? I posted a thread on here awhile back trying to look into my ABS code, but it was winter so I couldn't work on it. It's warm out now so now I want to fix it if it's cheap. My ABS light comes on as soon as the car gets up to about 3mph. I remember something about a specific common problem that happened with a part after 3mph. Anyone know what it would be? I seem to remember 'speed sensor' being thrown around.

 

MY ABS light is on. My buddy has SNAP ON reader. Will check and let you know what I find this weekend. BY the way my front left wheel bearing did sound like it was going so Im not sure if its related. You could start by seeing if any of the sensor wires are damaged on each wheel. On my blazer the dust shields are rusted away so it is possible for the sensor wire to rub the back of the rotor if not routed carefully.

 

likely a sensor issue. the ABS self tests every time you turn the vehicle on. when idling in park, if the light turns off after its self test, no fault is detected, meaning the abs motor and those components are testing normally. if the light comes on as soon as you begin movement, that means the voltage created by the speed sensors are different, or one or more arent creating voltage at all. check all the wiring at the sensors, then clean then with brake cleaner and wipe with a cloth. theyre magnetic, so rust and other metallic dust will stick to them. grab a feeler guage and check for the proper air gap. they must be a specific distance from the tone ring on the cv shaft. not sure what the spec is, do a search. also check to see id there is continuity in the sensors. a simple resistance check with a dvom will do. there will be a bit of resistance, but if theres an open, you know you have a bad sensor.

 

Keep in mind this is a 2000 blazer. it doesnt have the exposed abs sensor. A bad wheel bearing will cause the gap between the reluctor ring and sensor to vary. usually replacing the bearing solves the problem.

 

If your 2000 Blazer uses the same bearing assembly a my 2001 4x4 does...don't skimp on the bearing replacement. At a local "AZ" store, I was offered 2 options...the $129 version and the $199 version...well, duh...I was replacing both, so saving a total of $140 sure appealed.

Long story short, 4 months later (JUST past the cheaper one's 90 day warranty)...the ABS light goes on. pulling the wheel revealed the almost severed ABS sensor cable. There's a heavy metal crimp (not one easily pried open) and it was placed in the wrong location. But, failure on my part, I did NOT move the wheel through an extreme swing L-to-R. I would've caught it if I had. So, as cars have lived without ABS for years, I disabled the ABS (pulled the relay/fuse) until I can fix it. After 1 more month, now I have a very distinct speed-proportional "hum=VERY subtle vibration" that I'm guessing might be a bad bearing.

But, from experience, a bad/false reading ABS sensor is worse (and much more dangerous) than no ABS at all. False triggers caused erratic brake behavior and almost cost me a rear-end collision before I disabled it. If it is ABS, I'm no expert, but I'd consider yanking that relay unless you can immediately stop driving it and have it repaired.

 

Yea I agree, I just pull the fuse when the abs starts to kick in at the wrong time. Scary feeling when the brick wall keeps getting closer and closer and closer...