Diagnostics of Toyota automatic transmission faults
Visual inspection
* Check the level and condition of the transmission fluid.
* Check for leaks or damage to the automatic transmission housing and related components.
* Inspect electrical connectors and wiring for corrosion or damage.
Computer diagnostics
* Connect the scanner to the vehicle’s diagnostic port.
* Read trouble codes (DTCs).
* Determine the source of the problem based on DTCs.
Manual check
*Check the gear selector for proper operation.
* Make sure there is no slipping or jerking when changing gears.
* Perform a freewheel test in park or neutral to check for abnormal noise or vibration.
Diagnose faults based on symptoms
Delay or slippage when shifting gears
*Low transmission fluid level
* Contaminated transmission fluid
* Worn friction discs or spacers
* Problems with solenoid valves
* Malfunctions in the automatic transmission control unit
Shocks or knocks when shifting gears
* Dirty automatic transmission filter
* Low pressure in automatic transmission
* Worn gears or bearings
* Malfunctions in the torque converter
Humming or vibration when driving
*Low transmission fluid level
* Worn automatic transmission pump bearing
* Worn planetary gears
* Malfunctions in the torque converter
Transmission fluid leaks
* Damaged automatic transmission housing
* Leakage from gaskets or seals
* Worn torque converter
When driving, it is difficult to change gears or there is a loss of power
* Malfunctions in the automatic transmission control unit
*Wiring problems
* Malfunctions in the torque converter