Alero (Trac off, ABS, and Service Vehicle Soon lights on)

[Larson17]

So I was reading some of the threads on here because I've been having the same problem. Here's what I've come up with.

The wheel bearings in Alero's are NOT pressed in, therefore in order to fix it you would have to buy a brand new hub assembly and throw that on. Basically the difference between the two is that with the hub assembly, everything is enclosed and non-serviceable, including the vehicle speed sensor.

Some of the problems I've had with it so far is that all three of those lights (ABS, Trac Off, and Service Vehicle Soon) come on at the same time. Sometimes, right before they come on, the Low Trac light comes on for about ten seconds. The following are a few reasons this might be happening...

The wheel bearing is bad: Basically you'll have a whining noise coming from the wheels. The noise will get higher in pitch and louder when you go faster and faster. Don't get it confused with a slipped belt in a tire, or other tire problem, which is more of a rythmic thudding noise that gets faster as you speed up. Your car will basically sound like a boat the faster you go. It might be hard to determine which side it is, but what you can do is this simple test... Drive about thirty miles an hour, or until you hear the whining noise fairly well and constant. Take turns moving the wheel side to side and find out when the noise happens loudest. If it truly is a wheel bearing (unless both sides are bad) the noise should go away or greatly decrease when you turn to one side. So depending on when the noise is present or loudest will help you figure out which side it is. One very important thing you must remember though, and this is kinda the rule for this... If you're turning left and that noise is really loud, its your right side wheel bearing that needs replacement, and same with turning right, if you hear it turning right it's the left side. The reasoning behind this is because when you are turning right, all the weight of your car is pushed to the left side (Vice versa with turning left), being that the weight of your car is leaning left, your left wheel bearing now had more of a load on it, causing it to make noise. So helpfully that will help you a little. To repair this problem, you will have to replace the whole hub assembly. I've seen this as cheap as $85 to as expensive as $145. You can get it at any Napa, Autozone, or Carquest. Also junkyards are a good place to look. You could find a car that has a blown engine but all the suspension parts are intact.

Bad Vehicle Speed Sensor: This one will be kind of hard to diagnose, seeing as you can't hear or see anything that goes wrong with a sensor. Basically if the sensor fails for any reason, those lights will go on. You may be able to get a code from the car by hooking up an OBD II scanner, but sometimes these types of codes don't show up on there. If that doesn't work, you'll need to find somewhere that will test it with an ABS specific scanning device. This sensor is inside the hub assembly, so also, you'll have to buy that to fix this problem too.

ABS Wiring: So coming out of your hub assembly, you have two wires that are next to eachother in an insulation covering. This will have a connector that hooks up to a connector on your vehicles main wiring harness. This is the one that kills me, because I've seen it a hundred times. People will replace their hub assembly, connect the wires together, but forget to tie down or secure the ABS wire's themselves. What ends up happening is that those wires are freely moving, but are very close to your CV boot. In day to day driving, you will do a lot of turning, and when turning the wheel.... those wires are stretched across the constantly spinning CV boot, which will eat through that insulation. At first, the lights may be off and come on every once in a while. Basically when this happens, a small part of your ABS wire is exposed and shorts out to ground, (meaning that an exposed part of the wire is touching a metallic or semi-metallic object which allows the moving electrons (current/amps) to find a different path to travel down). When this happens, the electricity cannot complete its full path in the circuit, causing a warning light (or three...) to come on via electrical fail-safes. Depending on where in the wire this happens, there are different ways to repair it. If it's severed completely at the very end of the wire, you will most likely have to replace the whole hub assembly. If the wire is severed, or eaten into near the middle of the wire, you may be able to cut, strip, and solder the wires together, place electrical tape around the newly soldered wires, and securing down the ABS wires. MAKE SURE WHENEVER YOU DO A REPAIR TO HUB ASSEMBLIES TO SECURE DOWN THE ABS WIRES AND CONNECTOR TO PREVENT THIS PROBLEM. This has happened to me, and it has bugged me for a long time and is a pain in the ass.

Bad Relay or Fuse: If you see the little wavy metal strip inside the fuse is burnt out, replace the fuse. That will fix your problem for a short while, but seeing as fuses don't commit suicide... there has to be a reason the fuse died. Most likely (and pretty much the only reason fuses blow...) is because of high amperage. High amperage in an electrical circuit is caused by a mechanical bind. So if your wheel bearing is going bad, possibly causing damage or resistance to the speed sensor, this could cause the fuse to blow. Relays are a little different. Relays are basically a controlling device. They control low voltage circuits with high voltage (or vice versa, I'm kinda rusty on this one ). They consist of two connected terminals that are the powered part of the relay (85 & 86), and a terminal (30) that connects to either terminal 87 or 87A. If you read the resistance with an Ohm meter, there should be little resistance between 85 and 86, around 1 Ohm or less in the normally closed terminals (30 & 87), and O.L (out of limits/limit exceeded) in the normally open circuit (30 & 87A). If you don't find that those are the readings you get, you should replace the relay, which could have just gone bad by itself, its not necissarily the same as a fuse.

Well, I hope this helps you all a little bit. I've seen a lot of questions and debating on this subject in other threads, and I just hoped I could spread some light on this issue for everyone to look into.

Thanks for your time, and if you have any questions, feel free to ask. :-)

Josh

[qb9futurehof]

Thank you for the great information. i am with the other 99% of Alero owners who are having an issue like this, but this is very useful and should help to solve my issue, and take the DAMN lights off the dash.

[charles546]

i was looking for information on another subject.noticed this post have had same problem with 2002 alero and 2002 buick century.after hours of checking and double checking found problem on buick.my brothers alero was the same problem but oppisite side of car.the problem is one of the two wires in harness on car not sensor is broke into.on both of our cars it was about 6 inches back up the wires from where it plugs into the sensor.
hope this will help someone else.

charles546

[Festivus]

I have this same issue with a 2001 Alero. All 3 lights were on all of the time for weeks. Got the codes read, found out it was right front. Cleaned the connection with deoxIT and checked the wiring. Wiring looked fine. I did reinforce it where it bends a lot. Lights were then out. 2 hours later, they were on. Restarted car, they were off. Now they're on sometimes.

The intermittent lights seem to point to a wiring issue. But I can't find any spots where it looks like there is an issue. I have an electrical tester. Can I use that to detect an issue?

[charles546]

on both cars it was the green wire that was broke into.dont know if green wire is the voltage input wire or not.should be 5 volts going to sensor .when i pulled the wires out of the plastic tubeing which goes around wires could see the break it was before the clip that holds wires to bottom a-frame.hope this helps you.if you have any more questions post it and i will help all i can.
good luck charles

[Festivus]

I have 3 visible clips that hold the wire in place. 2 are straight out of where the wire comes out of the engine area. The last one is closest to the wheel, toward the back of the car just a bit. Is it next to this last one where the break in the green wire happened? I really checked it out closely the last time I had the wheel off and could see no issues.

[charles546]

wire on both cars was broke before it got to first clip.when i took wires out of the plastic tubeing they were visible for mabey 4 inches.then they were wrapped in some real hard plastic stuff.i think the green wire is power for sensor.there is a post on here somewhere mabey on buick century or pontaic grandprix that tells how to test the sensor.its been so long i cant remender but its there.i tested my sensor was good so checked wires and found problem.it was under a post about the lights being on on that vehicle.
good luck charles

[Festivus]

Sorry for asking again... So the wire was broken before the first clip, closest to the engine? Or the first clip closest to the wheel?

I'm betting that I have the same issue.

[charles546]

it was before the clip closest to the wheel.between clip and where it plugs into sensor.dont mind the questions thats what this website is for to try and help each other save a little money.i have got lots of help from it and sure did apperciate it.if you have any more just post and i will try and help all i can.

good luck charles

[Festivus]

Thanks. When I inspected it, there was a length of this connection about 1 1/2 inches long where there was no outer insulation. Seemed strange. Both wires underneath looked fine but I'll recheck them. It's the connection area between the first clip closest to the wheel and the second one closer to the engine. There is a sharp bend in it and logic would dictate that to be the problem area but I'm not certain.

I found this wiring online for $26. Called the ABS Harness. Is it difficult to replace? Seems that threading it through and connecting the end opposite the wheel might be tricky.

[charles546]

i didnt replace the wireing.first tried the little wire unions would only get good connection for few weeks then lights back on.done this three times on my buick.finally soltered a new piece of wire in bad spot has worked fine for about six months now.i would check to see if i had voltage comeing to sensor with voltage meter.if you do check sensor for contunity dont remember what reading should be.i will look and see if i can find that post that tells the readings for the sensor and post it for you.may take me a couple of days but think i can find it.

good luck charles

[charles546]

found a good post on buick century forum.use forum search ityped in test wheel speed sensor in the little box.the post 02 century codes has information that will help you.
good luck charles

[Festivus]

Well, I wasn't able to check the sensor side of the circuit my my meter (couldn't see inside the coupler) but I was able to check the other side. Got the same resistance reading as a back wheel so I think it's safe for me to assume that my wiring from the couple back to the engine is good. I really inspected the wires and they all looked just fine.

Might have to do the hub assembly next...

[charles546]

the connection where sensor plugs into wireing harness. it will come off the plate if i remember right just push it down then can turn sensor plug upsidedown where you can see inside the plug.that post on buick sensor has the reading it should be.

good luck charles`

[Festivus]

Yesterday I tried to replace the hub assembly. Broke a ratchet and some sockets trying to take off the caliper mounting bracket and the 3 bolts holding the back of the hub. Then I couldn't get the hub out no matter what I did. The thing simply would not budge. I didn't have a hub puller since most posts online advised that I wouldn't need one. Couldn't run out to get one as I was running out of daylight. So I just put it all back together.

Then I noticed the outer brake pad almost down to metal while the inner pad was 30 to 40%. The caliper must be sticking...

Wasted 5 hours yesterday.

So I dropped it off at the shop last night to get the caliper looked at, the pads replaced and rotors resurfaced, the hub replaced (hopefully they'll use my part), and the tires rotated.