Happy new year everyone.
Need some help. I've been having this weird issue on my CTS wagon (2013. 80k miles) where every time I stop at a light my CEL comes on (flashing) and the traction control goes off. Stabilitrak stays on. As soon as i start driving the traction control comes back on but the CEL stays for 30 sec or longer and it goes away.
What's weird is that once these lights happen the car shifts harder a bit jerkier (especially when it downshifts while coming to a stop) I feel a thud when it downshifts into 1st right before it stops.

I've read codes and there was a cylinder misfire (4th cyl) which I replaced the coil and plug. So that's good. The bearings have also been replaced on the right rear and driver front (I believe)

Not sure what's going on here. Any thoughts? Thanks in advance!

 

Hello- Do you have a good scanner, or know someone who does? The best course of action at this point is to get in there and see what codes are floating around in there. You may have an ABS fault in there that is causing this mayhem. The newer style ABS sensor rings, (and yours has this) are known to do this. The older, more reliable type was mounted on the outer rim of the half-shafts and sort of look like a bracelet. These were robust and lasted sometimes for the life of the vehicle. Apparently, GM thought that they lasted too long and in their infinite wisdom, switched to the next generation sensor rings. These are paper thin magnetic rings that are laminated to the outer face of the hub bearings. Well, have you ever seen a hub bearing that is on a vehicle for 6 or 7 years? It's rusty and crusty and nasty and no matter how that paper thin magnetic sensor ring is attached, that rust will work its way under it and crack it and de-laminate it and start to cause false ABS readings and wheel speed readings, thus creating all sorts of mayhem with your ABS system and your STABILTRAK system, etc. One of mine let go and even took out my ABS sensor. I had to replace a perfectly good hub bearing because of this. Just another poor design, courtesy of your GM design team. Throw a scanner on there and see of you have any ABS faults. It should even be wheel specific, so you can target where the problem is. Hope that helps.