DTC P0740-7E: Torque Converter Clutch Actuator Stuck On [11/2021 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus NX 350, 2024 Lexus NX 350, 2023 Lexus NX 350, and 2022 Lexus NX 350. However, it is still accessible from the selected car via links, so may be relevant.

The ECM uses signals from the throttle position sensor, mass air flow meter, transmission revolution sensor (NT), transmission revolution sensor (NC) and crankshaft position sensor to help determine the engagement timing of the lock-up clutch. The ECM monitors the engagement of the clutch using the transmission revolution sensor (NT), transmission revolution sensor (NC) and crankshaft position sensor.

Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect solenoid (SL) valve, transmission valve body assembly and torque converter assembly mechanical problems.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P0740-7E	Torque Converter Clutch Actuator Stuck On	All of the following conditions are met (2-trip detection logic): Engine coolant temperature is 40°C (104°F) or higher. ATF temperature is -10°C (14°F) or higher. The vehicle is being driven with the shift state drive (D). No malfunctions are detected in the solenoid (SL1, SL2, SL3, SL4, SL5, SL6, SL, SLU and SLT) valves, transmission revolution sensors (NT and NC), coolant temperature sensor, oil temperature sensor, knock sensor, crankshaft position sensor circuits, electronic throttle or CAN communication system. When the ECM commands the solenoid (SL) valve OFF, the difference between the turbine speed (NT) and engine speed (NE) is 170 rpm or more for 3.5 seconds or more.	Solenoid (SL) valve remains closed Transmission wire Transmission valve body assembly is blocked Torque converter assembly Automatic transaxle assembly (clutch, brake, gear etc.) Line pressure is too low	Comes on	DTC stored	SAE Code: P0741