- Low transmission fluid level
- Dirty or old transmission fluid
- Faulty shift solenoids
- Faulty transmission control module (TCM)
- Mechanical problems within the transmission, such as worn gears or a broken shift linkage
Diagnosis:
1. Check the transmission fluid level and condition. If the fluid level is low, add fluid until it reaches the proper level. If the fluid is dirty or old, it should be replaced.
2. Check the shift solenoids for proper operation. The shift solenoids are responsible for shifting the transmission into different gears. If a solenoid is faulty, it can prevent the transmission from shifting into second gear or any other gear.
3. Check the transmission control module (TCM) for proper operation. The TCM is responsible for controlling the transmission's operation. If the TCM is faulty, it can cause the transmission to shift erratically or not at all.
4. If the transmission fluid level is correct, the fluid is clean, the shift solenoids are operating properly, and the TCM is functioning correctly, then there may be a mechanical problem within the transmission, such as worn gears or a broken shift linkage. This will require further inspection by a qualified mechanic.
