Front wheel sensors

Is there a good description or manual to help in repair the front wheel abs sensors.I have to disconect the abs fuse because when using the brakes with the fuse in sometimes I have absolutly have no brakes the pedal is hard as a rock to push down.

What year, 2 or 4 wheel drive?

Go to this site I think it will be helpful to you:
http://www.autozone.com/az/cds/en_us/0900823d/80/08/84/4a/0900823d8008844a/repairInfoPages.htm

What year and is it a 4x4?There was a recall which does not fix it at all.The fix for the recall was to clean the wheel speed sensors and GM does not cover the wheel bearing under the recall.The only real fix is to replace the wheel bearings instead of replacing the speed sensors

I should have said what I have it is a 98 k1500 and wafrederick when I bought the truck of a 2 year lease I had this probleme and brought it to the dealer and that is what they did they cleaned it and it worked for about a year and then it came back since then I drive it with the fuse pulled. Other than that it is a great truck.

I hear about this a lot.My father's 2002 GMC Dually went through this and it was gone after replacing the left front wheelbearing.I replace the front wheelbearings a lot on GM fullsize trucks and the problem is fixed with the customer very happy.

So just by changing the front wheel bearings it should clear up the the problem, and what is making it bad in the first place?

I do not understand how a bad wheel bearing will cause a hard brake pedal.
wafredrick could you please explain how the bad bearings cause a hard pedal.

thanks for input

The wheel bearing failure can cause excess clearance in the sensor ring so the abs does not see a signal hence a possible abs issue, the more common problem of premature abs activation is usually caused by the mounting flange on the knuckle rusting and affecting the sensor. None of these issues can cause a hard pedal, if anything a really worn bearing that will move around, causes a low pedal.

Well I have to tell you I was surprised as hell when I could not push the brake pedal down fast enough before almost hitting a car at a stop light!!!!!!

I am at no means underestimating anyones knowledge or experience on this issue. I recommend having the abs system checked with a ABS capable scanning tool rather than throwing parts at it.

Would the abs module cause a hard pedal??

I am at no means underestimating anyones knowledge or experience on this issue. I recommend having the abs system checked with a ABS capable scanning tool rather than throwing parts at it.

Would the abs module cause a hard pedal??


I would check vacuum at brake booster engine running.... does it hold vacuum at booster with engine then shut down.....this would cause a hard brake pedal..... recall was for 99 on up for abs front wheel sensors.....could be abs unit causing loss of braking and by removal of fuse this is now inoperative...and braking is improved....

I never heard of abs causing hard pedal, but if its pulsing that would be abs......,and if it pulses when braking at low speeds this would be abs wheel sensors/or conn./wires etc...

When I did bring it back to the dealer when I first bought it about 3 times they said finally they replaced the bearings and there to this day is no abs codes that come up unless I pull the fuse even when the fuse is in and I can bearly push down the brake pedal I still get no codes or the abs light.It seems very strange how bearings can have this probleme with the sensors I do recall hearing it is in the shape of a star pattern (the sensor).

When I did bring it back to the dealer when I first bought it about 3 times they said finally they replaced the bearings and there to this day is no abs codes that come up unless I pull the fuse even when the fuse is in and I can bearly push down the brake pedal I still get no codes or the abs light.It seems very strange how bearings can have this probleme with the sensors I do recall hearing it is in the shape of a star pattern (the sensor).

you have a brake booster that is leaking or a bad vacuum line to booster.... this will cause hard pedal..... no abs codes,,,,this is more normal as abs causing hard pedal is not a failure that i have seen....

Would you agree that even if I take the abs fuse out I would notice a falling brake pedal that would not hold say at a stop light eventually the pedal would drop all the way down if it were a vacuume leak or a bad booster. When the fuse is out my brakes are perfect minus the abs feature.

Would you agree that even if I take the abs fuse out I would notice a falling brake pedal that would not hold say at a stop light eventually the pedal would drop all the way down if it were a vacuume leak or a bad booster. When the fuse is out my brakes are perfect minus the abs feature.

No I don't agree!

a soft /dropping brake pedal means a loss of brake fluid/defective master cylinder...

a hard brake pedal is loss of vacuum to brake booster/or brake booster has a leak.........

I still can't understand how the abs can cause a hard brake pedal.........in your vehicle......perhaps someone can explain how this can occur......

I had this same problem on my 95 blazer 4x4, Mine just had trash between the hub and the abs sensor, which made the abs think that wheel was locked up all the time, which made it impossible to push the brake and stop. I cleaned the trash out and its been fine ever since. Scared me too ended up running a stop sign lucky nobody was coming. Hope this helps.

I think on yours the sensor is on the outside of the hub? and on the 98 it inside the hub which makes it harder to repair more to take apart.

jcAT YOU ARE RIGHT NOW THAT i THINK ABOUT IT. But still would that still do the same thing even if the fuse was in or out. The booster would still have the same effect?

jcAT YOU ARE RIGHT NOW THAT i THINK ABOUT IT. But still would that still do the same thing even if the fuse was in or out. The booster would still have the same effect?

with the fuse in or out that feeds the ABS how does this effect brake pedal I don't understand with your vehicle..with the fuse in it causes a hard pedal??? perhaps the ABS is creating pressure in the brake system but how would you be able to move vehicle?

because power to ABS causes problems I would try a scap yard ABS to see it it corrects or changes the problem..unless some one can jump in with knowledge of this issue..

So it seems very strange that with the fuse in my brake pedal is rock hard to push and with the fuse out works like a champ. I do believe that getting another unit would not solve the problem wich I do know lies within the front wheel bearings/abs sensor. I am surprised that not a lot of people had this problem so it looks like when a nice weekend comes up I will open up one side to see how to fix it. Again I looked over the system and found no leakes on the vacuume side or fluid side thanks for the replies great web site

So it seems very strange that with the fuse in my brake pedal is rock hard to push and with the fuse out works like a champ. I do believe that getting another unit would not solve the problem wich I do know lies within the front wheel bearings/abs sensor. I am surprised that not a lot of people had this problem so it looks like when a nice weekend comes up I will open up one side to see how to fix it. Again I looked over the system and found no leakes on the vacuume side or fluid side thanks for the replies great web site


to check front abs sensors jack up both front wheels remove abs sensor electrical connector and while spinning the tire you should get 350-500milli volts a/c voltage....and both sides should read the same.... the lower side is the problem side, but with your problem both sides may be low as this is not a typical issue with the problems others have experienced if these sensors are not putting out the proper signal...

I have exactly the same problem with my 99 Tahoe. With the ABS fuse in, the pedal is very hard and the vehicle is hard to stop - at very low speeds only. Very scary at times. I pull the ABS fuse and the brakes work normally (no ABS of course). Pedal is not hard. I believe the wheel sensors are the problem and will be investigating soon - hopefully this weekend.

I have had my fuse out for so long Im surprised the dash indicator light hasnt burned out yet, it was only when I went to inspection that made figure I have to get this fixed.

I have had my fuse out for so long Im surprised the dash indicator light hasnt burned out yet, it was only when I went to inspection that made figure I have to get this fixed.


whenever you get this issue repaired post back with the details. thanks