Ok guys, have a weird one for ya. I just finished my front upper and lower CA bushing replace on both sides. Everything went smooth and I decided to take it out for a little spin today (2-3 miles) to see how it feels as I didn't want to drive too much as I need to get it alighned badly. Under light braking when the car gets down to about 10 mph the low trac light comes on and the ABS kicks in? I check the wheel speed sensor connections and they are both fully seated and and not loose and no clips were damaged during the disassembly and reassembly. Could the car being this bad out of alighnment cause a wheel speed sensor to trip the ABS? Anyone have any ideas as this seems weird to me?

 

I've had that happen when the rear sensor on the differential housing gets dirty (or out of adjustment with the Strange 12-bolt sensor). Maybe you got some dirt in the front sensors, or they moved slightly in the mounts. It seems like the sensor signal isn't picked up at very low speeds, the EBCM interprets that as "0" wheel velocity and activates the ABS. Really screws you when you're stopping a bit too close to the car in front of you!

 

Thanks for your advise Injuneer, what do you recc I do - Clean the sensor contacts?

 

Check the sensors on both sides for dirt, accumulated metal particles, etc. Blow them out with compressed air. I'm not sure if you can check the depth of the sensor in the spindle/bearing cartridge, but you might want to look at whether you can estimate the depth of the sensor on both sides, and whether they are different. Not even sure how much of the sensor you can see, because they are integral with the cartridge.

As far as the other question in your PM, alignment is not going to affect the ABS sensors.

 

Ok guys, still have the issue. Got it aligned today and it's straight as an arrow but the low trac is triggering and kicking on the ABS at around 5 mph. I have cleaned all the wheel sensor and connections to no avail. It's not triggering the ABS light just the low trac and if I do indeed have a bad wheel sensor how can I tell which one it is as I don't wanna start throwing parts at it as these hub assemblys are really expensive. No codes are being stored plus the ABS system is separate and can only be scanned by GM correct? Any ideas as this is really annoying and pretty dangerous at low speeds?

 

You can get a low $ ABS code scanner from Actron. I believe someone has it on sale right now for $180.

Determining exactly which sensor is activating the ABS might take something more than a code scanner, though. And minor point, but the "LOW TRAC" light doesn't trigger and kick on the ABS when the light comes on. The light comes on to show you when the ABS is activated.

 

Ok, good news, the problem is now fixed. Decided to bit the bullet and buy a new hub assembly (friend of mine at Advance got me 30% off) and since the odds are both didn't have a problem, I started with the driverside and worked from there. Replacing these things is a snap and took all of 10 mins. When I pulled the assembly off it turned out the sensor was not fully seated and looked to be poped out a bit, so I replaced it with the new hub and now no Low Trac light and stops on a dime without kicking on the ABS - YESSS. Thought I'd include some pics of the hub assembly and the sensor pulled off so you guys can get an idea of how this sucker works. Thanks for all your help fellas once again.

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