P0741
U660E 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) 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) 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 the shift solenoid SL. When the 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 the 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 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 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:
OFF malfunction::
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs DTC Check / Clear.
HINT
Using Techstream to perform Active Test 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 Test early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Test.
1. PERFORM ACTIVE TEST
(a) Warm up the engine.
(b) Turn the engine switch off.
(c) Connect Techstream to the DLC3.
(d) Turn the engine switch on (IG).
(e) Turn Techstream on.
(f) When using Techstream:
Enter the following items: "Powertrain / ECT / Active Test".
(g) According to the display on the tester, perform "Active Test".
HINT
- This test can be conducted when the vehicle speed is 37 mph (60 km/h) or more.
- This test can be conducted in the 6th 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 Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following items: "Powertrain / ECT / Trouble Codes".
(d) Read the DTCs using 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. 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:
OK -- CHECK SHIFT SOLENOID VALVE SL (OPERATION)
NG -- Continue to next step.
3. CHECK SHIFT SOLENOID VALVE SL (RESISTANCE)
(a) Remove the 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
OK -- REPAIR OR REPLACE TRANSMISSION WIRE
4. CHECK SHIFT SOLENOID VALVE SL (OPERATION)
(a) Remove the shift solenoid valve SL.
(b) Connect a positive (+) lead to the terminal of the solenoid connector, and a negative (-) lead to the solenoid body.
OK:
The solenoid valve makes an operating noise.
NG -- REPLACE SHIFT SOLENOID VALVE SL
OK -- Continue to next step.
5. CHECK TRANSMISSION VALVE BODY ASSEMBLY
OK:
There are no foreign objects on each valve and they operate smoothly.
NG -- REPAIR OR REPLACE TRANSMISSION WIRE
OK -- Continue to next step.
6. CHECK TORQUE CONVERTER CLUTCH ASSEMBLY
OK:
The torque converter clutch operates normally.
NG -- REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY