One of the more costly things to repair in your car is the transmission, and usually, diagnosing the problem involves taking out the entire transmission and disassembling it. When your car is unable to go into reverse, internal damage might be causing the problem. But before you take your car to a mechanic, you can look at various possible causes.
Look at your car’s transmission selector switch. Since 2001, car manufacturers have installed onboard computers, which have control over various car parts and functions, like the engine and transmission shifting. If you notice that the switch isn’t working, then the computer isn’t receiving the signal that the car should be shifting into reverse. The switches do become work over time because of corrosion. As a quick fix, go from Park to Low very quickly, repeating the action several times.