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 mechanical problems.
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
P0741 |
When both of the following are detected (2-trip detection logic):
|
|
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.
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.
(Engine speed is at least 70 rpm greater than the input turbine speed.)
MONITOR STRATEGY
Related DTCs |
P0741: Shift solenoid valve SL OFF malfunction Shift solenoid valve SL ON malfunction |
Required sensors/Components |
Shift solenoid valve SL, Speed sensor (NT), Speed sensor (NC), Crankshaft position sensor (NE), Throttle position sensor (VPA1), Mass air flow sensor (MAF), Transmission temperature sensor (THO1), Engine coolant temperature sensor (ECT) |
Frequency of operation |
Continuous |
Duration |
OFF malfunction 3.5 sec. |
MIL operation |
2 driving cycles |
Sequence of operation |
None |
TYPICAL ENABLING CONDITIONS
ALL:
The monitor will run whenever this DTC is not present. (Not circuit malfunction) |
P0712, P0713 (ATF temperature sensor circuit (TFT sensor)) P0115, P0117, P0118 (ECT sensor circuit) P0715, P0717 (Turbine speed sensor circuit) P0791, P0793 (Intermediate shaft speed sensor circuit) P0748 (Shift solenoid valve SL1 circuit) P0778 (Shift solenoid valve SL2 circuit) P0798 (Shift solenoid valve SL3 circuit) P2810 (Shift solenoid valve SL4 circuit) P2759 (Shift solenoid valve SLU circuit) P2769, P2770 (Shift solenoid valve SL circuit) P0327, P0328, P0332, P0333 (KCS sensor circuit) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0604, P0606, P060A, P060B, P060D, P060E, P0657, P1607, P2102, P2103, P2111, P2112, P2118, P2119, P2135 ((ETCS) Electronic throttle control system) U0100 (CAN communication system) |
ECT (Engine coolant temperature) |
40°C (104°F) or more |
Spark advance from Max. retard timing by KCS control |
0°CA or more |
Transmission range |
"D" |
TFT (Transmission fluid temperature) |
-10°C (14°F) or more |
TFT (Transmission fluid temperature) sensor circuit |
No circuit malfunction |
ECT (Engine coolant temperature) sensor circuit |
No circuit malfunction |
Turbine speed sensor circuit |
No circuit malfunction |
Intermediate shaft speed sensor circuit |
No circuit malfunction |
Shift solenoid valve SL1 circuit |
No circuit malfunction |
Shift solenoid valve SL2 circuit |
No circuit malfunction |
Shift solenoid valve SL3 circuit |
No circuit malfunction |
Shift solenoid valve SL4 circuit |
No circuit malfunction |
Shift solenoid valve SLU circuit |
No circuit malfunction |
Shift solenoid valve SL circuit |
No circuit malfunction |
(KCS) Knock control sensor circuit |
No circuit malfunction |
(ETCS) Electronic throttle control system |
Not system down |
CAN communication system |
Not system down |
Engine |
Starting |
TCM selected gear |
Not 1st |
Vehicle speed |
15.5 mph (25 km/h) or more |
Turbine speed/Output speed (NT/NO) with 1st |
3.304 to 7.724 |
Turbine speed/Output speed (NT/NO) with 2nd |
1.901 to 2.340 |
Turbine speed/Output speed (NT/NO) with 3rd |
1.399 to 1.649 |
Turbine speed/Output speed (NT/NO) with 4th |
0.998 to 1.138 |
Turbine speed/Output speed (NT/NO) with 5th |
0.705 to 0.836 |
Turbine speed/Output speed (NT/NO) with 6th |
0.568 to 0.695 |
TYPICAL MALFUNCTION THRESHOLDS
OFF malfunction:
Following conditions are met |
(a) and (b) |
(a) Engine Speed - Turbine speed |
70 rpm or more |
(b) Transmission fluid pressure switch |
ON |
CAUTION / NOTICE / HINT
NOTICE:
Perform the universal trip to clear permanent DTCs (See page ).
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.
Tester Display |
Test Part |
Control Range |
Diagnostic Note |
---|---|---|---|
Activate the Lock Up |
[Test Details] Controls the shift solenoid SLU and SL to set the automatic transaxle to the lock-up condition. [Vehicle Condition]
|
[Lock-up] 0: OFF 1: ON |
Possible to check SLU and SL solenoid operation. |
HINT:
(h) Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT:
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.
Display (DTC Output) |
Proceed to |
---|---|
Only "P0741" is output |
A |
"P0741" and other DTCs |
B |
HINT:
If any other codes besides "P0741" are output, perform the troubleshooting for those DTCs first.
B |
GO TO DTC CHART |
|
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:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
6 (SL) - Body ground |
20°C (68°F) |
11 to 15 Ω |
OK |
GO TO STEP 4 |
|
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:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
Solenoid Connector (SL) - Solenoid Body (SL) |
20°C (68°F) |
11 to 15 Ω |
*1 |
Shift Solenoid Valve SL |
OK |
REPLACE TRANSMISSION WIRE |
NG |
REPLACE SHIFT SOLENOID VALVE SL |
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.
Text in Illustration
*1 |
Shift Solenoid Valve SL |
NG |
REPLACE SHIFT SOLENOID VALVE SL |
|
5. |
INSPECT TRANSMISSION VALVE BODY ASSEMBLY |
(a) Check the transmission valve body assembly (See page ).
OK:
There are no foreign objects on each valve and they operate smoothly.
NG |
REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY |
|
6. |
INSPECT TORQUE CONVERTER ASSEMBLY |
(a) Check the torque converter assembly (See page ).
OK:
The torque converter operates normally.
OK |
REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY |
NG |
REPLACE TORQUE CONVERTER ASSEMBLY |
Interior lights list
Your Toyota is equipped with the illuminated entry system to assist in entering
the vehicle. Due to the function of the system, the lights shown in the following
illustration automatically turn on/off according to the presence of the electronic
key (vehi ...
Terminals Of Ecu
TERMINALS OF ECU
1. CHECK POWER BACK DOOR ECU (POWER BACK DOOR MOTOR UNIT) (w/ POWER BACK DOOR
SYSTEM)
(a) Disconnect the L20 power back door ECU connector.
(b) Measure the voltage and resistance according to the value(s) in the table
below.
...
Headlight Beam Level Control Actuator Circuit
DESCRIPTION
The headlight leveling ECU assembly actuates the headlight leveling motor according
to vehicle conditions.
WIRING DIAGRAM
PROCEDURE
1.
READ VALUE USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) ...