Chevy & GMC Vans

Hey guys, 1995 Astro AWD. My ABS light came on yesterday out of the blue while I was driving down the freeway and has been on ever since. I found it peculiar that it popped on while just driving down the freeway. Before it came on, my brake pedal was very very firm. Now it still stops fine, and the pedal isn't horrible, but it is noticeably softer than before the light came on.

I have tried doing a bit of searching, and am not really sure where to start, I suppose a good place to start would be to jump the aldl and try to pull the code, but I won't be able to that until tonight so I was hoping to get some ideas to brainstorm.

I just bought this van from the originial owner about a week and a half ago, and we were planning on taking our first trip to the mountains in it, but unless I get this resolved I won't be comfortable hitting up the mountains this weekend.

Thanks.

Could very well be dirty wheel sensors in the front. Might be a sign one of the hub bearings are on their way out. You can get a feel for them by jacking it up, pulling the front wheels off and remove the calipers and rotors. You can then spin the nubs over to see if you feel or see noise and/or play in them. Wiggle them up and down side to side to check for play. At this point, you can carefully pull the sensors out of the hub and clean them off.

If your van has 4 wheel ABS, you may have sensors on the rear axles. Look for wiring going to each side right on the axle. If there is no wires then no need to go further. If there is a wire to each side, pull the wheels off and remove the drums. Behind the brake shoes and hardware you will see the wires going to sensors that pick up a notched reluctor ring right on the axle shafts. There is most likely brake dust on them. Blow them off with compressed air. Just be careful of your eyes and breathing the dust.

Thanks for the reply. I have read about the the ABS sensor's commonly just needing to be cleaned, and it's a good easy place to start the troubleshooting. However, my main question/concern would still be that if it were just a dirty sensor leading to the ABS light being triggered, why would that affect my brake pedal feel? I will admit, I am not too well versed in brakes, I can change rotors/pads/calipers etc, but when it comes down to the in's and out's of the ABS system, I do not know it well.

I do believe that if the system is no longer in contact with the sensor (like if it becomes unplugged or a wire is broken) ABS light will trigger even if the sensor is clean. I believe the sensor is a Hall effect sensor. It would have to be seriously caked in metallic dust to malfunction.

I have no idea....but does the ABS light also indicate low brake fluid level as well?

There is also the possibility that the PO flushed the brake system and did not bleed it properly. There could be air bubbles in the ABS unit. You do need to cycle the unit with a dealer Tech II scantool to bleed the brakes properly.

PO didn't say anything about anything regarding a recent brake bleeding. I tried to get as much maintenance history as possible from him, especially since he was the original owner. Brake fluid level is good as of yesterday when I checked after the abs light initially came on.