Wheel speed sensor wires

SIUlero · 04-23-2007, 03:01 PM

Does anyone have a factory service manual? I'm trying to figure out which terminals at the pcm go to my front wheel speed sensors. A friend's Tech 2 told me I'm not getting any input from them but I tested them at the hubs and they seem to work fine (putting out an ac signal). I forgot to check the haynes at work yesterday but I doubt that would have told me where the wires go anyway.

Also I have a chirping/squealing noise coming from the front of my car only when I'm moving. It doesn't do it all the time, but often does it when I hit a bump. Too high pitched to be a bearing. Anyway, I'm gonna go see if I can find anything rubbing. If anyone has any ideas on this, let me know, thanks.

AftermathAlero · 04-23-2007, 04:25 PM

its the wheel bearing/HUB .. its sealed unit.. the speed sensor,abs.etc is all built in the hub. Around 120 bucks for a new one at autozone.

SIUlero · 04-23-2007, 04:44 PM

Actually it's cheaper for me cuz I work there. Anyway I just went out and tightened it up...should fix the chirping for a while. I think it's an aftermarket hub cause the nut on it is different from the driver's side, but the strange thing is there doesn't seem to be any way to lock it in place and keep it from coming loose again. I might have to get a second nut to jam it in place.

Cliff8928 · 04-24-2007, 02:56 AM

If i remember right, the wires from the wheel speed sensors only go to the EBCM, not the PCM.

SIUlero · 04-26-2007, 03:46 PM

Actually, that might be...I don't have a manual to look at so I was only assuming they went to the PCM. I can't tell the color of the wires at the hub connector because of the dirt on them, and they're twisted pair wrapped tight all the way from there up into the main loom. I guess I'll have to cut the wrap and find the colors, then hope I can find all four of them going into either one of the modules, unless someone knows what terminals they go to on the connector...the BCM is right next to the PCM under the dash, right? I'd really like to get this problem solved so 4 out of the 5 lights on my dash will go away.

olds03alero · 04-26-2007, 05:27 PM

just because its putting out an ac voltage doesn't mean its good. test the resistance of the hub, hook one probe from your multimeter to one wire, and the other one to the other wire. if it is over 1.5 M ohms its probably going bad. give me until tomorow when i go to work i'll look up the wiring diagram and post the colors for you. if you can give me either the exact code number or what the code says that will help a lot. also the noise your hearing over bumps is more than likely the upper part of the struts, gm has a tsb out about them. i'll try to post that as well.

SIUlero · 04-26-2007, 08:11 PM

OK, my resistance is WAY over 1.5M...it's infinite, on both sides. As for the sound, it wasn't the strut mounts, though I do have that thunking over bumps too. Turns out my passenger axle nut was loose and it let that hub get loose. I tightened it up as much as I could with a breaker bar, and I've got a co-worker with an air impact who'se gonna tighten it up the rest of the way for me. I don't have a bearing noise so it hasn't gotten serious yet. Still gonna have to replace it in the next couple months. I'll hold off on the other side for now. I would still like the wire colors and connector pins though, thanks! I don't remember the code numbers or descriptions, but I do know that the tech 2 was showing 0 mph on each front wheel while the rears kept up with vehicle speed, and I went up to around 15 mph.

Cliff8928 · 04-27-2007, 01:58 AM

Quote:

Originally Posted by SIUlero

Actually, that might be...I don't have a manual to look at so I was only assuming they went to the PCM. I can't tell the color of the wires at the hub connector because of the dirt on them, and they're twisted pair wrapped tight all the way from there up into the main loom. I guess I'll have to cut the wrap and find the colors, then hope I can find all four of them going into either one of the modules, unless someone knows what terminals they go to on the connector...the BCM is right next to the PCM under the dash, right? I'd really like to get this problem solved so 4 out of the 5 lights on my dash will go away.

Not the BCM (Body Control Module), but the EBCM (Electronic Brake Control Module). I believe it's attached to the ABS pump.

olds03alero · 04-27-2007, 08:15 AM

well if your resistance is infinite you definatley have an open in the hubs, you will need to replace them both to clear the code, as for the schematics i'll post them tonight after work.

SIUlero · 04-27-2007, 08:33 PM

I tested out a new hub at work today....WAY different readings than what mine have.....1.1M ohms and quite a bit more voltage at a much slower speed. I'm definitely gonna be replacing both sides as soon as I can afford it (one at a time, passenger first). Then I get an O2 sensor and my dashboard acne will be all cleared up!