Description and Operation

Description

The automatic transmission system relies on various measured data to determine the current control status and extrapolate the necessary compensation values. These values are used to control the actuators and achieve the desired control output. If a transmission problem, including a transmission problem, has been identified, perform a self-diagnosis and basic transmission inspection (fluid and oil level check), then inspect the control system components using the diagnostic tool.

Control System Components

Diagnostic Trouble Code Troubleshooting

It is equipped with a fail-safe mechanism that allows the vehicle to be driven home or to the dealer in the event of a transmission failure. The fail-safe mode is activated if a transmission malfunction occurs. In this mode, the transmission operates at a minimum level of functionality that allows the vehicle to reach a service center. Fail-Safe: allows the vehicle to be driven safely in the event of a malfunction. Limp Home: maintains minimum functionality (*) in the event of a malfunction, allowing the vehicle to reach a service center. (*) Minimum functionality: drive (fixed gear), reverse and neutral.

Self-Diagnosis

The TCM is in constant communication with the control system components (sensors and solenoids). If an abnormal signal is received for longer than the specified time, the TCM detects a malfunction, stores the diagnostic trouble code in memory, and then sends a malfunction signal through the self-diagnosis terminal. Such DTCs are stored independently of each other and are not erased even when the ignition is turned off or the battery is disconnected or the TCM connector is disconnected.

Disconnecting a sensor or actuator connector while the ignition switch is in the ON position causes a diagnostic trouble code (DTC) to be set and stored in memory. In this case, disconnecting the battery will not clear the diagnostic trouble code memory. Use a diagnostic tool to clear the diagnostic trouble code memory. Before removing or installing any component, read the diagnostic trouble codes, then disconnect the negative (-) battery terminal. Before disconnecting the battery cable from the battery terminal, turn the ignition switch to the OFF position. Removing or connecting the battery cable while the engine is running or the ignition is on may damage the TCM. When checking the charging system of the generator, do not disconnect the positive (+) battery terminal, to prevent damage to the ECM from voltage surges. When charging the battery with an external charger, disconnect the battery terminals on the vehicle side to prevent damage to the TCM.

Inspection Procedure (Self-Diagnosis)

When battery voltage is too low, diagnostic trouble codes cannot be read. Be sure to check the battery voltage and the charging system before starting the test. Diagnostic memory is erased if the battery or the TCM connector is disconnected. Do not disconnect the battery until the diagnostic trouble codes (DTCs) have been completely read and recorded.

Inspection Procedure (Using GDS)

1. 1
   Turn the ignition off.
2. 2
   Connect the GDS to the data link connector under the lower crash pad.
3. 3
   Turn the ignition on.
4. 4
   Use the GDS to check the diagnostic trouble code.
5. 5
   Repair the faulty part according to the diagnostic flow chart.
6. 6
   Erase the diagnostic trouble code.
7. 7
   Disconnect the GDS.

Perform TCM learning after replacing the automatic transmission to prevent slow transmission response, acceleration shock and start-up jerking. (Refer to "Automatic Transmission Control System (Repair Procedures)" in this group.) Add automatic transmission fluid. (Refer to "Automatic Transmission System" in this group.) After servicing the automatic transmission or TCM, clear the diagnostic trouble codes (DTCs) using the GDS tool. Diagnostic trouble codes (DTCs) cannot be cleared by disconnecting the battery.