"Service Traction System," "Trac Off," What's going on?
 

Hey guys, been quite a while since I've been here. Over the past few months I've come across this issue with my 05 Monte. At about 73k miles, I started the car up and the instrument panel lit up with warnings about the Traction system (see title). It will remain lit until I turn the car off, not to return again in any kind of pattern whatsoever. Sometimes I'll go weeks without seeing it, sometimes it'll be there when I turn the car on three times in a row. Sometimes it'll be 60 degrees, sometimes it'll be 20 degrees outside. It's completely random and I don't notice anything different about the way the car drives or sounds or feels. I was told it may be a wheel speed sensor, but if that were the case, wouldn't the warnings be more common or have some kind of common factor in when they appear?

I really have no idea what's going on. I don't think it's affecting the car any, if anything it's like it's lonely and just wants my attention :p

But seriously, anyone have a clue what's going on here?

It's most definitely your wheel hub assemblies. Either the connection the the hub is dirty and throwing the codes every now and then, or the hub is just starting to go bad.

ABS code reader (not basic OBD2 reader) can tell you exactly which one is the problem.

The code reader isn't practical due to how randomly this happens. Do you know why the frequency of the warning lights is all over the place instead of more consistently? I've never heard of or had something go wrong in the car that hasn't thrown a warning out incessantly.

I also had mu hubs checked out (I worked at an auto parts store with some very skilled mechanic buddies, so I trust them, and they showed me exactly what they were looking at) and they said the hub was fine. But perhaps I'll have them take another look.

I've had that come up once on my 05 - turned the car off then on and it went away - never happened again so far - probably one of the sensors was dirty.

The PCM monitors a signal from the sensors. If the connection to a sensor is loose/dirty that signal may become interupted and the signal will be momentarily lost. That would cause the PCM to set the code. If the hubs are good try cleaning the connections to the sensors and see if that resolves the problem.

I will try it when I can. Thanks.

The hubs can be fine and pass the mechanics test, but since the ABS wheel speed sensor is inside the hub, it's possible the sensor in it has failed and the only way to replace it is to replace the hub.
If someone has an ABS scan tool, I believe it can pull historical data (so even if the code is not active, you may still be able to see what code/wheel issued it).

It might be good to check the basics. Make sure the cable connects are good and nothing has chewed up the wiring (my Grand Am went without ABS for a few months and I found the wire connecting to the speed sensor was severed, quick fix and all better).

If you choose to go the "easy route" and change the hub assembly on whichever wheel is throwing the error, I'd change the pair instead of just one. If it's the right front, change the left as well. I've gone through seven or eight of these in my '03 and they do tend to go in pairs. I'll swap one and a week later (or less) the other one goes. Always the front as well - I've never changed a rear.

My Mom's 02 use to go off but only when it got wet.

Changing in pairs is probably not a bad idea (since in theory they should be worn equally).

I've had some cars I've only done one bearing on and others where I had what you mentioned (changed one, only to find BOTH were bad at the same time).

But not bad advise if one can afford to do both.

FYI - Over the summer, I changed one (and only one) on my Monte, but I also changed two on a '97 Grand Prix and my wife's '05 Impala (did one only to find after a test drive the other one was ALSO bad). So there is a stat for ya (two may be the best way to go).