P0741

U341E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0741: Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)

DTC P0741 - Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)

DESCRIPTION

The ECM uses the signals from the throttle position sensor, mass airflow 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 mass 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 turbine speed signal 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 and stores the DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

The following conditions are common to OFF malfunction and ON malfunction.






OFF malfunction





ON malfunction





TYPICAL MALFUNCTION THRESHOLDS

OFF malfunction





[ON malfunction]
- 2 detections are necessary per driving cycle.
1st detection: Temporary flag ON
2nd detection: Pending fault code ON
Vehicle speed must be under 10 km/h (6.2 mph) once before 2nd detection.

ON malfunction





INSPECTION PROCEDURE
HINT: Using a Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

1. PERFORM ACTIVE TEST
(a) Warm up the engine.
(b) Turn the ignition switch to OFF.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the tester ON.
(f) Enter the following menus: Powertrain / Engine and 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 60 km/h (36 mph) or more.
- This test can be conducted in the 3rd or 4th 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.)





PROCEDURE

1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0741)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the tester ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs using the Techstream.
Result:





HINT: If any other codes besides "P0741" are output, perform the troubleshooting for those DTCs first.

B -- GO TO DTC CHART
A -- Continue to next step.
2. INSPECT SHIFT SOLENOID VALVE SL





(a) Remove the shift solenoid valve SL.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Connect the positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.
OK:
The solenoid valve makes an operating sound.
NG -- REPLACE SHIFT SOLENOID VALVE SL
OK -- Continue to next step.
3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
OK:
There are no foreign objects on each valve and they operate smoothly.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- Continue to next step.
4. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY
OK:
The torque converter clutch operates normally.
NG -- REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY
OK -- REPAIR AUTOMATIC TRANSAXLE ASSEMBLY