Troubleshooting

Diagnostic Trouble Code Troubleshooting

Has a fail-safe mechanism that provides "limp home" with 4th gear hold so the vehicle can be driven to the owner's home or a dealer. Fail-safe: the TCM provides 4th gear hold and reverse gear operation in the event of a malfunction. Limp home: maintains minimum functionality (Drive (4th gear hold), Reverse) in the event of a malfunction, allowing the vehicle to reach a dealer. Self-diagnosis: The Transmission Control Module (TCM) constantly communicates with the control system components (sensors and solenoids). If an abnormal signal is received for longer than the preset duration, the TCM detects the malfunction, stores the DTC in memory, and then sends a malfunction signal through the self-diagnosis terminal. Such DTCs are stored independently and will not be erased even if the ignition is turned off, the battery is disconnected, or the TCM connector is disconnected.

Disconnecting the sensor or actuator connector while the ignition switch is ON generates a Diagnostic Trouble Code (DTC) and stores it in memory. In this case, disconnecting the battery will not clear the diagnostic trouble code memory. Use the scan 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. Turn the ignition switch to the OFF position before disconnecting the battery cable from the battery terminal. Removing or connecting the battery cable while the engine is running or the ignition is ON may damage the Transmission Control Module (TCM). When checking the generator charging condition, do not disconnect the battery "+" terminal, to prevent damage to the Engine Control Module (ECM) from voltage. 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.

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.

After replacing the automatic transmission, use GDS to reset (erase TCM learning values). Then perform the Transmission Control Module (TCM) learning procedure to ensure optimal shift quality. (Refer to Automatic Transmission Control System - "Repair Procedures") Add automatic transmission fluid. (Refer to Hydraulic System - "Fluid") After servicing the automatic transmission or TCM, clear the Diagnostic Trouble Code (DTC) using the GDS tool. DTCs cannot be cleared by disconnecting the battery.

Symptom Troubleshooting

Symptom of Malfunction	Suspected Area	Remedy
Shift Delay	Clutch or brake damaged Faulty hydraulic control Faulty hydraulic pressure supply X X X	Clutch, Brake Solenoid valve, valve body Electric oil pump Mechanical oil pump Automatic transmission fluid cleanliness (foreign matter) Automatic transmission fluid level
Vehicle vibration during shifting Shift shock X X X X X X	Clutch or brake damaged Faulty hydraulic control Faulty hydraulic pressure supply Faulty transmission mount Faulty speed sensor Faulty harness Damaged connector and wiring	Clutch, Brake Solenoid valve, valve body Electric oil pump Mechanical oil pump Automatic transmission fluid cleanliness (foreign matter) Automatic transmission fluid level Speed sensor and connector Transmission harness and connector Vehicle connector and wiring
Fixed gear (shifting not possible)	Faulty solenoid valve Faulty TCM program X X X X X X X	Clutch, Brake Solenoid valve, valve body Electric oil pump Mechanical oil pump Automatic transmission fluid cleanliness (foreign matter) Automatic transmission fluid level Speed sensor and connector Transmission harness and connector Vehicle connector and wiring
Limited gear (shifting possible)	Faulty lock-up switch Faulty hydraulic pressure supply X	Lock-up switch and connector Vehicle connector and wiring Power
Driving not possible	Faulty CAN communication	CAN communication line TCM, ECU Power
Poor acceleration	Faulty hydraulic control Faulty hydraulic pressure supply X X X X X	Solenoid valve, valve body Electric oil pump Mechanical oil pump Automatic transmission fluid cleanliness (foreign matter) Automatic transmission fluid level Vehicle connector and wiring Power