Please let me know if this topic has been discussed elsewhere. Hate to repeat it.
2011 C6 GS MT Mag Ride. 33K miles. I removed both front wheels to install flares. Jacked car at the drivers corner for that wheel, then at the passengers side for that one. Removed the wheel. Installed the flare, put wheel back on. Drove car and got on it a little. Not bad. But after about an hour, I got DIC messages of "Service Traction Control System" and "Service Active Handling System". As well, "service engine light" came on as well as the "traction control off light"........the little car with burn out marks behind it. Car started running rough. Loss of power. Got home, checked the codes with reader. P0304 #4 misfire. Cleared code. Drove car. Messages and lights returned in just a few minutes. Figuring it had to be something associated with the wheel bearing hub and speed sensor. Took wheels back off, cleaned connectors with electric cleaner. Re-installed wheels. Still getting messages, lights, and #4 misfire code. Even if I turn off both active and traction control. I know there is a module behind the radiator that could cause problems, along with the steering wheel position sensor. But I'm trying to stick with the obvious. Hoping for some ideas before I replace both front hub bearing assemblies.

 

check spark plug wires on #4 cylinder (2nd cyl on passenger side, i believe..). If you have a misfire, the trac control will turn off.

Strange it happens with the tire swap but it prob happened after you got on it.

 

Good to know! I’ll check the plug.

 

Sure enough.....#4 plug wire had come off. Hopefully there is a fix for preventing that from happening in the future. I could do without that headache!

Thanks for the tip!

 

One thing you should do is coat the plug end with dielectric grease as well as the coilpack ends. After installing the wires, burp the coilpack end with a precision screwdriver or by pinching. you'll hear a small "pfft" as the trapped air leaves.