AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0741
| DTC Code | DTC Name |
|---|---|
| P0741 | Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL) |
DESCRIPTION
The ECM 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 ECM monitors the engagement of the clutch using the turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor.
Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect mechanical problems of the shift solenoid valve (SL), valve body and torque converter.
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
MIL |
Memory |
|---|---|---|---|---|---|
P0741 |
Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL) |
Lock-up does not occur when requested (2-trip detection logic). |
|
Comes on |
DTC stored |
MONITOR DESCRIPTION
Torque converter lock-up is controlled by the ECM based on speed sensor NT, speed sensor NC, engine speed, engine load, engine temperature, vehicle speed, ATF temperature and gear selection. The ECM determines the lock-up status of the torque converter by comparing the engine speed (NE) to the input turbine speed (NT). The ECM calculates the actual transmission gear by comparing the input turbine speed (NT) to the counter gear speed (NC). When conditions are appropriate, the ECM 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 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 shift solenoid valve SL or lock-up system performance. The ECM will turn on the MIL and store the DTC.
Example:
When 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 ECM commands lock-up.
(Engine speed is at least 70 rpm more than the input turbine speed.)
WIRING DIAGRAM
Refer to DTC P2769.
CAUTION / NOTICE / HINT
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
PERFORM ACTIVE TEST
Tip:Using the GTS 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.
Warm up the engine.
Turn the ignition switch off.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Active Test.
According to the display on the GTS, perform the Active Test.
Powertrain > Engine and ECT > Active Test
Tester Display
Measurement Item
Control Range
Diagnostic Note
Activate the Lock Up
Control shift solenoid valve SLU and SL to set the automatic transaxle to lock-up
ON or OFF
Can be used to check shift solenoid valve SLU and SL operation.
[Vehicle Condition]
Vehicle speed: 60 km/h (37 mph) or more
Powertrain > Engine and ECT > Active Test
Tester Display
Activate the Lock Up
Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
Tip: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
CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0741)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Powertrain > Engine and ECT > Trouble Codes
Read the DTCs using the GTS.
Result
Result
Proceed to
Only P0741 is output
A
P0741 and other DTCs are output
B
Tip:If any other codes besides P0741 are output, perform the troubleshooting for those DTCs first.
INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL)
-
*a
Component without harness connected
(Transmission Wire)
Remove the wiring harness connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
A-6 (SL) - Body ground
20°C (68°F)
11 to 15 Ω
Result
Proceed to
OK
NG
NG INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)Click here
-
INSPECT SHIFT SOLENOID VALVE SL (OPERATION)
-
*1
Shift Solenoid Valve SL
Remove shift solenoid valve SL.
Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.
OK
Measurement Condition
Specified Condition
Battery positive (+) → Shift solenoid valve SL connector
Battery negative (-) → Shift solenoid valve SL body
Valve moves and makes an operating noise
Result
Proceed to
OK
NG
-
INSPECT TRANSMISSION VALVE BODY ASSEMBLY
Check the transmission valve body assembly.
OK
There are no foreign objects on any valve.
Result
Proceed to
OK
NG
INSPECT TORQUE CONVERTER ASSEMBLY
Check the torque converter assembly.
OK
The torque converter operates normally.
Result
Proceed to
OK
NG
INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)
-
*1
Shift Solenoid Valve SL
Remove shift solenoid valve SL.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
Shift solenoid valve SL connector terminal - Shift solenoid valve SL body
20°C (68°F)
11 to 15 Ω
Result
Proceed to
OK
NG
-