The codes you have are all related to the instrument cluster/CAN
920 Cluster / no speed message from the PCM
921 Cluster / no distance signal from PCM
999 Indicated an error message is saved and to retrieve them via the cluster trip odometer reset button.
Have you checked to see if the same codes are stored?
As far as the issue, it sounds like there is a breakdown of communication via the CAN bus system or the cluster itself is bad. Is the vehicle running properly? Other than the issues with the cluster, is the transmission still causing issues? Is the vehicle drivable?
If you look below, I attached the diagnostics for the codes. Take a look through them and let me know if you are comfortable performing them. Also, let me know if you have other questions.
See pics below.
Images (Click to enlarge)
Sunday, November 21st, 2021 AT 7:13 PM