Speedometer and Odometer intermittently

[Tubinfool]

I have a 2013 Subaru Outback. The speedometer and the odometer work intermittently. Sometime the speedometer will not work at all and sometimes it seems to be fine and then the needle jumps to 80 or 100. I noticed that when this started the time pressure light was also coming on but when the speedometer and the odometer work is the off. Sometimes now when they don't work tire pressure warning stays off. Also the radio volume does not work and my son who had the car while we were away for several months says the radio issue predated the speedometer and odometer issue. When a diagnostic meter is attached it reads no errors. That is true both for mine and the more sophisticated one used when I got an oil change and asked the mechanic to check to see if the Vehicle Speed Senson was an issue, since that if what I read initially when I was looking for help on line. I was wondering if the car has a loose wire some which is why the speedo goes in an out.
Any help whould be appreciated.
(By the way, tubinfool comes from my work as a paramedic doing endotracheal intubation. )

 

[Ecmbuster]

And the mystery transmission is? Have a professional test the transmission output speed signal.
Test the ABS speed sensors for relative speed and the battery level of the TPMS sensors.
An oscilloscope is required for the correct measurement.
That cheap "diagnostic meter" will never read the SSM (Subaru Select Monitor) Protocol network controllers.