Code No.P1774: UD Solenoid Valve System
SOLENOID VALVE SYSTEM CIRCUIT
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OPERATION
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DIAGNOSIS CODE SET CONDITIONS
If the drive terminal voltage of the UD solenoid valve is 3.0 V or less, it is judged that there is a short-circuit or open circuit in the UD solenoid valve, and diagnosis code P1774 is set.
If diagnosis code P1774 is set 4 times, the transmission is fixed in 3rd as a fail-safe measure.
PROBABLE CAUSES
- Malfunction of UD solenoid valve
- Damaged harness wires and connectors
- Malfunction of the A/T-ECU
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STEP 1. M.U.T.-III diagnosis code
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Q.
Are diagnosis codes P1775 and P1776 set?
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 Go to Step 9.
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 Go to Step 2.
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STEP 2. M.U.T.-III actuator test
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Item 2: UD solenoid valve
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OK: Operating sound can be heard.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent Malfunction ).
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Go to Step 3.
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STEP 3. Connector check: B-108 A/T control solenoid valve assembly connector
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Check for the contact with terminals.
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the defective connector.
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STEP 4. Measure the resistance at A/T control solenoid valve assembly connector B-108.
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Disconnect the connector, and measure the resistance between terminal No.3 and No.9 at the solenoid valve side.
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OK: 2.7 -
3.4 Ω
(A/T fluid temperature 20°C)
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Q.
Is the check result normal?
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Go to Step 5.
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Check the UD solenoid valve and solenoid valve harness.
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STEP 5. Measure the voltage at A/T-ECU connector C-34.
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(1)Connect A/T control solenoid valve assembly connector B-108.
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(2)Turn the ignition switch to the ON position.
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(3)Measure the voltage between A/T-ECU connector C-34 terminal No.41 and earth.
OK: 6-9 V
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Q.
Is the check result normal?
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Go to Step 8.
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Go to Step 6.
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STEP 6. Connector check: A-10 intermediate connector, C-34 A/T-ECU connector
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Check for the contact with terminals.
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Q.
Is the check result normal?
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Go to Step 7.
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Repair the defective connector.
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STEP 7. Check the harness between A/T control solenoid valve assembly connector B-108 terminal No.3 and A/T-ECU connector C-34 terminal No.41.
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Check the output line for short or open circuit.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the wiring harness.
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STEP 8. M.U.T.-III actuator test
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Item 2: UD solenoid valve
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OK: Operating sound can be heard.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent Malfunction ).
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Replace the A/T-ECU.
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STEP 9. Connector check: B-108 A/T control solenoid valve assembly connector
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Check for the contact with terminals.
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Q.
Is the check result normal?
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Go to Step 10.
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Repair the defective connector.
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STEP 10. Measure the resistance at A/T control solenoid valve assembly connector B-108.
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Disconnect the connector, and measure the resistance between terminal No.3 and No.9 at the solenoid valve side.
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OK: 2.7 -
3.4 Ω
(A/T fluid temperature 20°C)
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Q.
Is the check result normal?
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Go to Step 11.
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Check the solenoid valve harness.
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STEP 11. Connector check: A-10 intermediate connector, A-16X A/T control relay connector
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Check for the contact with terminals.
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Q.
Is the check result normal?
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Go to Step 12.
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Repair the defective connector.
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STEP 12. Check the harness between A/T control solenoid valve assembly connector B-108 terminal No.9 and A/T control relay connector A-16X terminal No.3.
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Check the power supply line for short or open circuit.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the wiring harness.
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