Advanced Diagnostics

Advanced Diagnostics - DTC P0741: Torque Converter Clutch Hydraulic Circuit Stuck OFF










General Description
The power transfer capacity of the torque converter clutch is controlled by the balance of automatic transmission fluid (ATF) supplied to and discharged from the torque converter clutch and the torque converter. When hydraulic pressure supplied to the torque converter clutch is less than the torque converter internal pressure, lock up is off. When hydraulic pressure supplied to the torque converter clutch is greater than the torque converter internal pressure, lock up is on. As the hydraulic pressure supplied to the torque converter clutch is increased, the power transfer capacity of the torque converter clutch is increased. The supply of hydraulic pressure is switched by shift solenoid valve C and the lock-up shift valve. When the powertrain control module (PCM) turns on shift solenoid valve C, the hydraulic pressure is supplied to the torque converter clutch. When the PCM turns off shift solenoid valve C, the hydraulic pressure is not supplied to the torque converter clutch. The balance of hydraulic pressure supplied to the torque converter clutch and the torque converter is controlled by A/T clutch pressure control solenoid valve D and the lock-up control valve. When the PCM turns on A/T clutch pressure control solenoid valve D, the power transfer capacity of the torque converter clutch is at its maximum. When the PCM turns off A/T clutch pressure control solenoid valve D, the power transfer capacity of the torque converter clutch is at its minimum. If the ratio of engine speed and input shaft (mainshaft) speed is not about 1:1 while the PCM is issuing the command to turn shift solenoid valve C and A/T clutch pressure control solenoid valve D on, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
The ratio of the engine revolutions to the transmission input pulses does not reach about 100 % for at least 22 seconds.

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.
2. Drive the vehicle at a constant speed of 60 mph (96 km/h) for at least 22 seconds.

- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, a Confirmed DTC and the freeze data are stored. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.