Possible reasons:
Mechanical problems:
* Wear or damage to reverse clutches in automatic transmission
* Failure of the reverse gear engagement mechanism (solenoid, servo)
* Insufficient transmission fluid level or poor quality
* Worn or broken planetary gear for reverse gear
Electrical problems:
* Faulty reverse gear solenoid or servo
* Open circuit or short circuit in wiring
*Transmission control module (TCM) malfunction
Other problems:
* Engine problems (eg insufficient power)
* Problems with the braking system (such as a stuck parking brake)
* Differential wear
Diagnostics:
1. Check the level and condition of the transmission fluid.
2. Study the vehicle’s service and repair history to identify possible problems with the automatic transmission.
3. Use an OBD-II scanner to check for transmission-related trouble codes.
4. Perform a visual inspection of the automatic transmission and related components for leaks, damage or wear.
5. Carry out a test drive to check the operation of the automatic transmission in all gears, especially in reverse.
Solution:
The solution to the problem depends on the identified cause:
* Replacement of clutches or reverse gear mechanism
* Adding or replacing transmission fluid
* Repair or replacement of reverse gear solenoid or servo
* Correct wiring or TCM faults
* Troubleshooting engine or brake problems
* Repair or replace differential