I have a 2001 Lexus es300. Has anyone had the knock sensor or heard of a knock sensor causing a transmission not to shift or loose reverse without throwing a code?

 

Hello,

Knock Sensor code does cause a pretty severe Limp Mode, forcing the Ignition Advance to 0, drastically reducing the performance, and disabling Overdrive (4th gear).

With that, I've never heard of it immobilizing the car completely, or disabling Reverse Gear, the issue likely runs deeper and will require expert evaluation, it will be very hard to judge anything over the wire.

Hope this helps and best of luck!