P0741
U760E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0741: Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)
P0741 - Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)
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 mechanical problems.
MONITOR DESCRIPTION
Torque converter lock-up is controlled by the TCM based on the speed sensor NT, speed sensor NC, engine speed, engine load, engine temperature, vehicle speed, ATF temperature and gear selection. The TCM determines the lock-up status of the torque converter by comparing the engine speed (NE) to the input turbine speed (NT). The TCM calculates the actual transmission gear by comparing the input turbine speed (NT) to the counter gear speed (NC). When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to shift solenoid valve SL. When shift solenoid valve SL is turned on, it applies pressure to the lock-up relay valve and locks the torque converter.
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 to be 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 more 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
OFF malfunction
TYPICAL MALFUNCTION THRESHOLDS
OFF malfunction
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
1. ACTIVE TEST
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.
(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.
ECT
(h) Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT
- When depressing the accelerator pedal while driving, if the engine speed does not change abruptly, lock-up is on.
- When decelerating, slowly release the accelerator pedal, but do not fully release it (fully releasing the pedal will close the throttle valve and lock-up may be turned off).
PROCEDURE
1. CHECK DTC 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 troubleshooting for those DTCs first.
B -- GO TO DTC CHART Automatic Transaxle System - U760E
A -- Continue to next step.
2. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL)
(a) Remove the TCM.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)
OK -- Continue to next step.
3. INSPECT SHIFT SOLENOID VALVE SL (OPERATION)
(a) Remove shift solenoid valve SL.
(b) Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.
OK:
Text in Illustration
NG -- REPLACE SHIFT SOLENOID VALVE SL Disassembly
OK -- Continue to next step.
4. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly Disassembly.
OK:
There are no foreign objects on any valve.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Removal
OK -- Continue to next step.
5. INSPECT TORQUE CONVERTER ASSEMBLY
(a) Check the torque converter assembly Testing and Inspection.
OK:
The torque converter operates normally.
NG -- REPLACE TORQUE CONVERTER ASSEMBLY Removal
OK -- REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Removal
6. 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:
Text in Illustration
NG -- REPLACE SHIFT SOLENOID VALVE SL Disassembly
OK -- REPLACE TRANSMISSION WIRE Removal