P0741
U241E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0741: Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve DSL)
DTC P0741 - Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve DSL)
DESCRIPTION
The ECM uses the signals from the throttle position sensor, mass air-flow meter, turbine (input) speed sensor, intermediate (counter) shaft speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.
Then the ECM compares the engagement conditions of the lock-up clutch with the lock-up schedule in the ECM memory to detect mechanical problems of the shift solenoid valve DSL, valve body and torque converter clutch.
MONITOR DESCRIPTION
Torque converter lock-up is controlled by the ECM based on the speed sensor NT, speed sensor NC, engine rpm, engine load, engine temperature, vehicle speed, transmission temperature and gear selection.
The ECM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm control voltage to counter gear rpm (NC). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the shift solenoid valve DSL. When the DSL is turned on, it applies pressure to the lock-up relay valve and locks the torque converter clutch.
If the ECM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the ECM interprets this as a fault in the shift solenoid valve DSL or lock-up system performance.
The ECM will illuminate the MIL and store the DTC.
Example:
When any of the following is met, the system judges it as a malfunction.
1. 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 ECM commands lock-up.
(Engine speed is at least 100 rpm greater than input turbine speed.)
2. 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 ECM commands lock-up OFF.
(The difference between engine speed and input turbine speed is less than 35 rpm.)
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All
OFF Malfunction
ON Malfunction
TYPICAL MALFUNCTION THRESHOLDS
Either of the following conditions is met: OFF malfunction or ON malfunction
OFF Malfunction
ON Malfunction
WIRING DIAGRAM
INSPECTION PROCEDURE
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 / Engine and ECT / Active Test.
(g) Follow the instructions on the Techstream and 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 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 the accelerator pedal in order to decelerate. (Do not fully release the pedal as that will close the throttle valve and lock-up may be turned OFF.)
PROCEDURE
1. CHECK ANY 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 / Engine and 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
A -- Continue to next step.
2. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE DSL)
(a) Disconnect the B20 transmission wire connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- INSPECT SHIFT SOLENOID VALVE DSL
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
(a) Disconnect the B33 ECM connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. INSPECT SHIFT SOLENOID VALVE DSL
(a) Remove the shift solenoid valve DSL.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Connect the battery positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid body. Then check that the valve moves and makes an operating sound.
OK:
Valve moves and makes operating sound.
NG -- REPLACE SHIFT SOLENOID VALVE DSL
OK -- Continue to next step.
5. CHECK TRANSMISSION WIRE
OK:
The connectors and pins are securely installed.
There is no open or short on the wire harness.
NG -- REPAIR OR REPLACE TRANSMISSION WIRE
OK -- Continue to next step.
6. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly.
OK:
There are no foreign objects on each valve.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- Continue to next step.
7. 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
OK -- REPAIR AUTOMATIC TRANSAXLE ASSEMBLY