I am getting my brake and ABS lights on intermittently. They come on for a while and go of. I am thinking wheel speed sensor but sometimes the lights come on at startup. This would indicate a hard code and usually an ABS unit problem. My Snap-On brick will not read the ABS codes from the ALDL connector. Any thoughts?

Honestly 95% of the abs codes are cause by rear wheel speed sensor

One of my front wheel sensors set the brake lite on mine. I would defer to mopartechnician on the frequency of front or rear being the most prevalent.

Seth, I would normally agree with you on the rear4 sensor but I am having no problems with my speedometer. About a year ago I had to replace the transmission output speed sensor but those symptoms were bad shifting with no codes. I had a rather interesting experience the other day that makes me think front sensor or even the ABS unit itself. I came out of the store and got in the truck and turned the key on, I usually wait for all of the noises to end before starting. One of those normal noises is the ABS unit which gives a "CHUNG" and then the brake and abs lights go out. This time the noise was delayed. When I was driving out of the parking lot I hit the brakes and something just did not feel right but I was going very slow so I could not pin it down. I pulled out on the highway and came up to a red light and hit the brakes and NOTHING!!!!! It was like stepping on a rock, the pedal did not move. I pushed hard and the abs came on and it jerked HARD left and then stopped straight. It has not done that again but I have noticed that at key on when I hear the abs right away the lights do not come on but if it is delayed they are on at startup. When driving they go on and off sometime and others they stay on for hours or off for hours. During the on times the brakes feel normal. Being a longtime mechanic I do not want to throw parts at it till the problem goes away, I want to identify the problem and fix that. Hopefully the added info will be something that someone has run across.Rick

ABS codes should be read with a DRBIII tool. Now since you rear sensor seems to be working and no complaints of the speedometer being dead. Then I'd would be looking at the front axle sensors. In this case you are stuck replacing both sensors as a pair. (Left & Right) you can't replace 1 sensor because the other old sensor will not match with the other front new sensor.

Thanks Mike, so you are saying I have to replace both fronts or none due to compatibility issues? Can the abs lock out one front wheel alone? If so that would indicate the right side is the bad one due to the issue I mentioned earlier.

Had my light coming on randomnly, ended up being front pass side. Replaced and all's good

Im putting ball joints in a 01 and it does not have sensors on the front hubs. This is the first truck ever that i have done with no front speed sensors

No ABS? You would have to have front sensors for either 4 wheel or rear wheel ABS.I just priced those sensors on Rock Auto, OUCH!! 130.00!

I have not had time to do anything with this but I have been watching far any kind of pattern. This afternoon I started it up and was sitting there contemplating a deer in the yard and noticed the ABS and brake lights would come on for about a minute and then turn off, usually the brake light first followed a few seconds later by the ABS light. Then in a minute or so they would come back on. I watched this happen for roughly ten minutes, on and off. I then drove off and the pattern continued but the lights were seperated for a while with the ABS light coming on for 10 seconds before the brake light and sometimes even alternating. I unplugged the harnesses from the ABS unit and all that comes on then is the ABS light with no brake light. There is no fluid level sensor on the master cylinder. Still looking for ideas, especially since I saw the price of the front sensors. I don't want to replace parts that are not needed.

I believe 00 was the first year of front abs along with the slip on rotors. That's odd that an 01 would not have them, maybe it was just an option and not standard equipment.Sent from my DROID4 using Tapatalk

I have 4 wheel ABS on mine. 1998.5

I have 4 wheel ABS on mine. 1998.5

Pictures or it didnt happen! Sent from my DROID4 using Tapatalk

I have a 95 v10 2500 with 4 wheel abs. My 97 cummins 3500 was RWAL only - no front sensors. I really wish it didn't take a drb (and attendant $90 dealer diag fee) to pull abs codes. Abs light has been on in my 07.5 since before I got it. No cruise control is the only symptom I care about. Tapatalking in traffic

That is where I like my '96. All I need is a test light to pull my ABS codes. Just touch the popper terminal in the OBD connector and count the blinks of the ABS light.

Learn something new every day! I have yet to see an early 2nd gen with pressed on rotors with front abs. You would think that would not be an option, I could see an option for a comfort feature but usually once they make a change to a safety function it is more often standard equipment. Sent from my DROID4 using Tapatalk

Pictures or it didnt happen! Sent from my DROID4 using Tapatalk

What do you want pictures of? I can get some shots of the brake lines coming out of the ABS unit or maybe the sensor wires on the front wheels. I am not going to pull the wheels just to get pictures of the sensors. Actually I still have the window sticker, I will see if it is listed there.

OK, I am back on this since I have had to use the truck in the snow and it would be nice to have the ABS. I think I can eliminate the wheel sensors because they are two wire sensors which means they generate a signal so they are doing nothing at rest. I am getting the lights on and off while sitting at idle. I have unplugged every plug related to the brakes and also the main harness plug, all are clean. Any ideas? I am on a very limited income and headed towards disability soon so I cannot afford to give a dealer a couple hundred dollars just to hook up a scanner.