Troubleshooting

Troubleshooting

Limp Home Mode

• Has a fail-safe function that prevents hazardous situations in the event of a transmission failure. The vehicle will be driven in limp home mode if the transmission malfunctions. In this mode, the transmission operates at minimum functional level (fixed gear, limited shifting, reverse, neutral), allowing the vehicle to reach a service center.

Limp Home Mode: Limited Shifting Mechanical Limp Home Mode: Fixed Gear (mechanical part failure, solenoid valves, TCM, CAN communication)

Troubleshooting

Symptom		Suspected Area	Remedy
Shift Delay / Shift Shock While Driving	1st → 2nd or 2nd → 1st	1. Malfunction of solenoid valve 28, OD&LR (If the 4th to 5th shift operates normally, replace solenoid valve 28) 2. Malfunction of LR brake	1. Replace the malfunctioning solenoid valve. 2. Inspect the clutch/brake for malfunction. - Disc damage - Piston D-ring damage - Clutch seal damage ※ Replace the transmission assembly if clutch/brake is damaged. ※ If shift shock occurs, check the manual shift position and reproduce the symptoms.
	2nd → 3rd or 3rd → 2nd	1. Malfunction of solenoid valve 37R, 28 (If the 1st to 2nd shift operates normally, replace solenoid valve 37R) 2. Malfunction of 37R, 28 clutch
	3rd → 4th or 4th → 3rd	1. Malfunction of solenoid valve 46, 37R (If the 2nd to 3rd shift operates normally, replace solenoid valve 46) 2. Malfunction of 46, 37R clutch
	4th → 5th or 5th → 4th	1. Malfunction of solenoid valve OD&LR, 46 (If the 3rd to 4th shift operates normally, replace solenoid valve OD) 2. Malfunction of OD, 46 clutch
	5th → 6th or 6th → 5th	1. Malfunction of solenoid valve 46, OD&LR (If the 4th to 5th shift operates normally, replace solenoid valve 46) 2. Malfunction of OD clutch
	6th → 7th or 7th → 6th	1. Malfunction of solenoid valve 37R, 46 (If the 4th to 5th shift operates normally, replace solenoid valve 37R) 2. Malfunction of 37R, 46 clutch
	7th → 8th or 8th → 7th	1. Malfunction of solenoid valve 28, 37R (If the 3rd to 4th shift operates normally, replace solenoid valve 28) 2. Malfunction of 28, 37R clutch
Shock Offset When Stopped	N → D / N → R	1. D position: malfunction of solenoid valve UD. 2. R position: malfunction of solenoid valve 37R. 3. Malfunction of UD/37R clutch.	1. Replace solenoid valve UD. 2. Replace solenoid valve 37R. 3. Inspect UD/37R clutch.
Shock Noise	P → D	Noise occurs when releasing the parking pawl	Normal
Vibration When Stopped (in N position)	N	Malfunction of solenoid valve UD	Replace solenoid valve UD
Delay/Jerk When Throttle Is Applied		1. ECM/TCM mismatch 2. Malfunction of torque converter damper clutch solenoid valve. 3. Oil pressure leak in the torque converter oil flow path. 4. Low fluid level	Check current status using Diagnostic Tester 1. Update ECM/TCM 2. Replace valve body assembly. 3. Replace torque converter and check fluid level.
Gear position indicator on instrument cluster flashes		Oil pressure characteristic values not entered	Enter oil pressure characteristic values
Mechanical Limp Home Mode (locked in 5th)		Solenoid valve malfunction	Replace the malfunctioning solenoid valve
		TCM error	Replace the engine control module
		CAN Communication Error	Inspect the CAN communication line
		Position switch malfunction	Replace position switch
			Inspect the position switch connector connection.
Soft Limp Home Mode (5th locked, 2nd–5th manual shift enabled)		Input and output speed sensor malfunction	Replace speed sensor
		Connector connection malfunction	Inspect main connector connection
			Replace main harness
Manual shift disabled		TCM error	Replace the engine control module
		Connector connection error	Check the shift lever connector connection
		Manual shift switch malfunction	Replace the shift lever

▶ Self-Diagnosis
The Transmission Control Module (TCM) constantly communicates with the system components (sensors and solenoids). If an abnormal signal is received for longer than the specified time, the TCM detects a malfunction, stores the DTC in memory, and then sends the malfunction signal through the self-diagnosis terminal. Such DTCs are stored and are not erased even when the ignition is turned off, the battery is disconnected, or the TCM connector is disconnected.

Disconnecting a 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 DTC memory. Use the diagnostic tester to clear DTC memory. 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 switch is ON may damage the Transmission Control Module (TCM). When checking the generator charging condition, do not disconnect the battery positive (+) terminal, to prevent damage to the Engine Control Module (ECM) from voltage. When charging the battery with an external charger, disconnect the battery terminals from the vehicle to prevent damage to the TCM. When battery voltage is too low, diagnostic trouble codes cannot be read. Be sure to check the battery voltage and charging system before starting the test.

▶ Inspection Procedure (Using Diagnostic Tester)

1. 1
   Turn the ignition off.
2. 2
   Connect the diagnostic tester to the data link connector (DLC) located at the lower instrument panel.
3. 3
   Turn the ignition on.
4. 4
   Use the diagnostic tester to check the diagnostic trouble code (DTC).
5. 5
   Repair the faulty part according to the diagnostic flow chart.
6. 6
   Erase the diagnostic trouble code.
7. 7
   Disconnect the diagnostic tool.