Possible reasons for the lack of gear shifting and increased speed in an automatic transmission (automatic transmission):
Electrical problems:
* Faulty gear selector position sensor
* Failure of the electronic control unit (ECU) of the transmission
*Wiring problems
Mechanical problems:
* Worn or damaged clutches
* Faulty torque converter
* Problems with gear shift mechanisms
*Low or contaminated transmission fluid
Hydraulic problems:
* Clogged or faulty valve body
* Faulty oil pump
* Fluid leakage from the system
Other possible reasons:
* Faulty engine control module (ECU)
* Problems with the brake system
Troubleshooting:
1. Check the level and condition of the transmission fluid.
2. Read fault codes using a scanner.
3. Check the integrity of electrical connections and wiring.
4. Check the gear selector switch.
5. Conduct diagnostics of the hydraulic system.
6. Carry out mechanical diagnostics of the automatic transmission.
Attention:
Troubleshooting automatic transmission problems on your own is not recommended. Contact a qualified mechanic or authorized service center for professional diagnosis and repair.