P0741
U760E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0741: Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)
P0741 - Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)
SYSTEM DESCRIPTION
The TCM uses signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor to help determine the engagement timing of the lock-up clutch. The TCM monitors the engagement of the clutch using the turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor.
Then the TCM compares the engagement condition of the lock-up clutch with the lock-up schedule in the TCM memory to detect shift solenoid valve SL, valve body and torque converter clutch mechanical problems.
MONITOR DESCRIPTION
Torque converter lock-up is controlled by the TCM based on the speed sensor (NT), speed sensor (NC), engine rpm, engine load, engine temperature, vehicle speed, transmission fluid temperature, and gear selection. The TCM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input turbine rpm (NT). The TCM calculates the actual transmission gear by comparing the input turbine rpm (NT) to the counter gear rpm (NC). When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to shift solenoid SL. When SL is turned on, it applies pressure to the lock-up relay valve and locks the torque converter clutch.
If the TCM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the TCM interprets this as a fault in shift solenoid valve SL or lock-up system performance. The TCM will turn on the MIL and store the DTC.
HINT
Example:
When any of the following is met, the system judges it as a malfunction.
- There is a difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up.
- (Engine speed is at least 70 rpm greater than the input turbine speed.)
- There is no difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up off.
- (The difference between the engine speed and input turbine speed is less than 20 rpm.)
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
ALL:
TYPICAL MALFUNCTION THRESHOLDS
OFF malfunction:
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
HINT
Using the 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 off.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / ECT / Active Test.
(g) According to the display on the Techstream, perform the Active Test.
HINT
* This test can be conducted when the vehicle speed is 60 km/h (37 mph) or more.
(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 Techstream on.
(d) Enter the following menus: Powertrain / 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 Automatic Transaxle System - U760E
A -- Continue to next step.
2. CHECK TRANSMISSION WIRE
(a) Remove the TCM from the transaxle.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Result:
B -- INSPECT SHIFT SOLENOID VALVE SL (OPERATION)
A -- Continue to next step.
3. INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)
(a) Remove shift solenoid valve SL.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE SHIFT SOLENOID VALVE SL Removal
OK -- REPLACE TRANSMISSION WIRE Removal
4. INSPECT SHIFT SOLENOID VALVE SL (OPERATION)
(a) Remove shift solenoid valve SL.
(b) Connect a battery positive (+) lead to the terminal of the solenoid valve connector, and a negative (-) lead to the solenoid body. Then check that the valve moves and makes an operating sound.
OK:
Valve moves and makes an operating sound.
NG -- REPLACE SHIFT SOLENOID VALVE SL Removal
OK -- Continue to next step.
5. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly Removal.
OK:
There are no foreign objects on each valve and they operate smoothly.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Removal
OK -- Continue to next step.
6. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY
(a) Check the torque converter clutch assembly Testing and Inspection.
OK:
The torque converter clutch operates normally.
NG -- REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY Removal
OK -- REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Removal