Code No. P0741: Abnormality in Lockup Function
DIAGNOSTIC FUNCTION
Abnormality is detected by the CVT-ECU when the torque converter slip speed is high during lockup control.
JUDGEMENT CRITERIA
- While the lock-up control, all the conditions listed below remain for 30 seconds.
- Slip speed is higher than the judgement value.
- The lock-up differential pressure is more than 0.2 MPa.
PROBABLE CAUSES
- Malfunction of the CVT assembly (Faulty lockup solenoid valve or valve body assembly)
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STEP 1. Check the following connector
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Check the terminals for a contact status problem and internal short circuit.
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Q.
Is the check result normal?
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Go to Step 2.
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Repair the defective connector.
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STEP 2. Measure the output wave pattern of the lockup solenoid valve at CVT-ECU connector (LULS terminal).
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(1)Connect the CVT assembly connector.
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(3)During the lockup control.
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(4)Connect an oscilloscope, and measure the voltage between CVT-ECU connector LULS terminal and body earth. OK: A wave pattern such as the one shown on (Check Procedure Using an Oscilloscope) should be output, and the maximum value should be 11 V or more and the minimum value should be 1 V or less. There should be no noise in the output wave pattern.
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Q.
Is the check result normal?
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Go to Step 3.
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Refer to diagnosis code No. P2763: Lockup Solenoid Valve (open circuit/ short to power supply) , or diagnosis code No.P2764: Lockup Solenoid Valve (short to earth) .
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STEP 3. Symptom recheck after erasing diagnosis code
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to the LOCK (OFF) position, and then wait for one minute. Then drive the vehicle until the engine has been warmed up.
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(3)Check if the diagnosis code is stored.
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Q.
Is the diagnosis code stored?
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Replace the CVT assembly.
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions .).
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