Can not select reverse gear - 2009 Proton Savvy 1.2

if first gear is easy to engage ( no noise , then the problem is in the reverse gear selection not a clutch adjustment problem

reverse in a non synchro gear so any vehicle movement while selecting it will cause it to grate
other than that it is a problem in the transmission

It's inside the transmission. The shift yoke probably has worn so much that it no longer moves the gear inside.

Mark, reverse linkage/cable out of adjustment or a bad reverse gear/fork/bearing.

There's no pin as such. An automatic gearbox does have solenoids for operating valves.
A valve can become stuck.

Reverse gear is first gear - when you select reverse a 'cog' moves onto first gear to reverse the direction of the gearbox output shaft - giving you reverse.

It may well be a stuck valve. Try selecting reverse a few times after the car has been run and the fluid is hot. A stuck valve (in the transmission) may free itself

Page 88 of your owners manual....

Reverse Sensing System (Park assist) (if equipped)
This feature sounds a warning tone to warn the driver of obstacles near
the rear bumper, and functions only when R (Reverse) gear is selected.
1. Select this function from the
SETUP menu to disable the reverse
sensing system feature.
2. Press the RESET control to turn
the rear park assist OFF. When R
(Reverse) gear is selected, PARK AID OFF will be displayed.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

You say that the reverse lights go out when reverse gear is selected! At what point are they on? Before reverse is selected?

Replace your Transmission Range Sensor (Also called "Neutral Safety Switch") It is located on top of the transmission housing under the shift lever where the shift cable hooks up.

pardo me for asking but is there not a method of selection of rverse gear by either pressing or lifting the gear lever so it will move over further so as to select reverse? or a lift up circular boss on gear lever itself that has to be lifted then reverse position can be selected ? hope this helps ?

Check for wear in the gear lever selector/gate mechanism.
It may have allowed the lever to select reverse, the 'jump' the lockout gate back to neutral position for selection of forward gears.
You may be able to de-select reverse if you access the lever directly at the gearbox case.

Does the gear selector show that is in reverse? Does the transmission have gear selector solenoids on the transmission? If so, may be a bad reverse select solenoid. Do the 'backup' lights come on when reverse is selected?