Code No.34: Free-wheel engage solenoid valve system
OPERATION
The system voltage from the ignition switch is imposed
to the free-wheel engage solenoid valves (terminal No.1), when the driving
condition is shifted to 2WD the terminal No.41 of the transfer-ECU is
grounded, which operates the free-wheel engage solenoid valves.
DIAGNOSIS CODE SET CONDITIONS
In the case that the free-wheel
engage solenoid valves operation and free-wheel engage solenoid valves
operation command (transfer shift lever, front propeller shaft speed sensor
and rear propeller shaft speed sensor) do not match, the code No.34 is set as
the open circuit or the short circuit of the free-wheel engage solenoid valve
system.
PROBABLE CAUSES
- Malfunction of free-wheel engage solenoid valve
- Damaged harness wires and connectors
- Malfunction of the transfer-ECU
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STEP 1. M.U.T.-III data list
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Item 30: Free-wheel engage solenoid valve
(Refer to data list reference table  ).
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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 2.
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STEP 2. Check the free-wheel engage solenoid valve.
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Refer to GROUP 26 - On-vehicle Service .
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Q.
Is the check result normal?
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Go to Step 3.
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Replace the free-wheel engage solenoid
valve (Refer to GROUP 26 - Solenoid Valve and Vacuum Hose ).
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STEP 3. Measure the voltage at free-wheel engage solenoid valve
connectors A-34 and A-35.
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(1)Disconnect the connectors, and measure the voltage between
terminal No.2 and earth at the wiring harness side.
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(2)Turn the ignition switch to the ON
position.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 4.
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STEP 4. Connector check: A-15 J/C (2), A-34, A-35 free-wheel engage
solenoid valve connectors, D-241 intermediate connector, D-405 J/B
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 5.
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Repair
the defective connector.
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STEP 5. Check the harness between free-wheel engage solenoid valve
connectors A-34, A-35 terminal No.2 and J/B connector D-405 terminal
No.25.
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Check the power supply line for short
circuit.
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Q.
Is the check result normal?
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Go to Step 10.
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Repair
the wiring harness.
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STEP 6. Measure the voltage at transfer-ECU connector
D-123.
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(1)Disconnect the connector, and measure the voltage between
terminal No.41 and earth at the wiring harness side.
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(2)Turn the ignition switch to the ON position.
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(3)Transmission gear should be neutral
position.
OK:
- When the transfer shift lever position is other than 2H, voltage
should measure system voltage.
- When the transfer shift lever position is 2H, voltage should measure 1
V or less.
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Q.
Is the check result normal?
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Go to Step 9.
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Go to Step 7.
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STEP 7. Connector check: A-16 J/C (3), A-34, A-35 free-wheel engage
solenoid valve connectors, A-03 <LHD>, D-137
<RHD>, D-225 intermediate connectors, D-123 transfer-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 8.
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Repair
the defective connector.
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STEP 8. Check the harness between free-wheel engage solenoid valve
connectors A-34, A-35 terminal No.1 and transfer-ECU connector D-123
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 10.
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Repair
the wiring harness.
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STEP 9. Connector check: D-123 transfer-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 10.
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Repair
the defective connector.
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STEP 10. M.U.T.-III data list
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Item 30: Free-wheel engage solenoid valve
(Refer to data list reference table ).
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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 transfer-ECU.
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