I have had the dreaded faults for close to 7 months now. They were intermittent in the beginning, but then were constantly on. I had steering angle, yaw rate, and DSC errors. I used an INPA software program and serial-usb cable from China to access the computer to find this information.
My errors resulted in loss of cruise control, HDC, DTC, 4x4, turn signal constantly on, and loss of brake assist. The turn signal was the most annoying so I attempted this fix to see if it would work.
This was a great DIY. I read up on another one that was a DIY guide for the sport steering wheel upgrade as well for further clarity. I took out the optical dis and cleaned it well like a DVD or CD using 100% isopropyl alcohol. There was quite a bit of crystallized build-up. I also used a Q-tip soaked with alcohol to clean the LED. Then I put everything back together and it did not fix my errors unfortunately. However, the turn signal issue went away surprisingly.
I then thought it might be my alignment since I noticed in the software that I still had yaw rate and steering angle sensor errors. My car drifts a little to the left. Low and behold, I got it aligned, used the software to run the longitudinal sensor calibration and all errors went away, YAY!
I am still happy i took the gunk off of the optical disc because that is just some nice security going forward. So all is well and I saved a lot of money!