Possible reasons for engaging only second gear in the automatic transmission:
1. Malfunctions of the gear selector position sensor:
* The sensor is faulty and does not transmit information correctly to the control unit.
* Fault in the sensor wiring.
2. Problems with the automatic transmission control unit:
* A malfunction in the control unit that prevents other gears from being engaged.
* Violation of programming of the control unit.
3. Malfunctions of the gear shift mechanism:
* The shift mechanism is stuck or worn, preventing it from engaging other gears.
* Damage to the second gear shift fork.
4. Insufficient oil pressure in the automatic transmission:
*Low transmission fluid level.
* Faulty oil pump or valve.
5. Worn or damaged clutches:
* Worn or damaged clutches may not be able to handle the torque of other gears.
6. Damage to the torque converter:
* Damage to the torque converter can cause problems with power transfer to other gears.
Diagnostics:
To determine the exact cause of the problem, it is necessary to diagnose the automatic transmission at a specialized service. Diagnostics may include:
* Scan fault codes.
* Checking the oil pressure in the automatic transmission.
* Checking the resistance of the gear selector position sensor.
* Visual inspection of the gear shift mechanism.
Remedy:
Depending on the identified cause of the problem, automatic transmission repair may include:
* Replacement of the gear selector position sensor.
* Reprogramming or replacement of the automatic transmission control unit.
* Repair or replacement of the gear shift mechanism.
* Filling or replacing transmission fluid.
* Replacement of worn or damaged clutches.
* Repair or replacement of the torque converter.