I have the 2008 model.
I had to use the newer remote to unlock the car. That works as it should with all buttons.
The well used remote is the problem.

Just pressing all the buttons on the older remote when outside the car none of the buttons work. the 5 micro switches on the remote circuit board are all reading on/off when checked with a meter.
I opened it up and checked the battery voltage on the circuit board where the battery connects. reads 3 volts. So I presumed that the battery is OK and power is getting to the circuit board.

When putting it in the dock it allows the car to start Ok. So took the circuit board out and tried just the case and car wouldn't start so it look like circuit board is working, sort of.

Do you think there is any point in replacing the battery?
thanks from
Mike L.