Absolutely a speed sensor can be causing all the issues you are experiencing. If there is a fault, the speed could be wrong, the CC may not work, and oftentimes (if equipped) the ABS, traction control, and stability control can fail.
I calculated the tire size difference. Here are my calculations:
205 60 15 = 817 revolutions per mile
205 60 16 = 786 revolutions per mile
Based on that, the speedo should be working the opposite of what you are experiencing.
The VSS can be the issue, but it's odd that it happened with the tire change and in the opposite manner I would have thought. What I suggest is to have the computer scanned for diagnostic trouble codes.
I have a list of codes that are related to the VSS. However, I don't want to send you on a wild goose chase. If you can, have the computer scanned to see what is indicated, if anything. Here is a video showing how it's done:
Most parts stores will do that for you. If you can, see if there is something stored. If there isn't we will start with one diagnostic at a time.
Let me know.
Friday, July 9th, 2021 AT 9:08 PM