P0741
DTC P0741 Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)SYSTEM DESCRIPTION
The ECM uses the signals from the throttle position sensor, Air-flow meter, turbine (input) speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.
Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect a mechanical problems of the shift solenoid valve SL, valve body and torque converter clutch or automatic transaxle (clutch, brake or gear etc.).
MONITOR DESCRIPTION
Based on the signals from the throttle position sensor, the airflow meter and the crankshaft position sensor, the ECM sends a signal to the shift solenoid valve SL to regulate the hydraulic pressure and provide smoother gearshifts.
The shift-solenoid valve SL responds to commands from the ECM. The valve controls the lock-up relay valve to perform torque-converter lock-up and flexible lock-up functions.
The ECM compares the engine rpm (NE) signal and the input speed calculated by output speed sensor (output speed) and gear ratio to detect torque converter lock-up.
The ECM then compares the lock-up status against the lock-up schedule in the ECM memory. If the ECM does not detect lock-up at the appropriate time, it will conclude that there is a malfunction of shift solenoid SL. The ECM will illuminate the MIL.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
Part 1:
Part 2:
TYPICAL MALFUNCTION THRESHOLDS
INSPECTION PROCEDURE
HINT: Performing the ACTIVE TEST using the intelligent tester allows the relay, VSV, actuator and so on to operate without parts removal. Performing the ACTIVE TEST as the first step of troubleshooting is one method to shorten labor time.
It is possible to display the DATA LIST during the ACTIVE TEST.
1. PERFORM ACTIVE TEST
(a) Warm up the engine.
(b) Turn the ignition switch off.
(c) Connect the intelligent tester together with the CAN VIM (controller area network vehicle interface module) to the DLC3.
(d) Turn the ignition switch to the on position.
(e) Turn on the tester.
(f) Select the item "DIAGNOSIS / OBD/MOBD / ECT / ACTIVE TEST".
(g) According to the display on the tester, perform the "ACTIVE TEST".
HINT:
^ This test can be conducted when the vehicle speed is 58 km/h (36 mph) or more.
^ This test can be conducted in the 3rd or O/D gear.
(h) Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT:
^ When changing the accelerator pedal opening angle while driving, if the engine speed does not change, lock-up is on.
^ Slowly release, but not fully, the accelerator pedal in order to decelerate. (Fully releasing the pedal will close the throttle valve and lock-up may be turned off.)
Step 1:
Step 2-4:
