Code No. C1422: Power supply low voltage
Code No. C1423: Power supply high voltage
OPERATION
- If the easy select 4WD, rear differential lock system <Vehicles with rear differential lock system> and freewheel mechanism <Vehicles with freewheel mechanism> does not work, or does not communicate with the M.U.T.-III, transfer-ECU power supply circuit, earth circuit, or transfer-ECU may have a problem.
- If the super select 4WD and rear differential lock system <Vehicles with rear differential lock system> does not work, or does not communicate with the M.U.T.-III, transfer-ECU power supply circuit, earth circuit, or transfer-ECU may have a problem.
DIAGNOSIS CODE SET CONDITIONS
- When power supply voltage drops to 9.7 V or less, code No.C1422 is set as low voltage.
- When power supply voltage rises to 16.3 V or more, code No.C1423 is set as high voltage.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Malfunction of the transfer-ECU
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STEP 1. Resistance measurement at transfer-ECU connector (GND1 terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the transfer-ECU connector (GND1 terminal) and body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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 Go to Step 3.
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 Go to Step 2.
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STEP 2. Check of open circuit in GND1 line between transfer-ECU connector and body earth.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction  ).
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Repair the connector(s) or wiring harness.
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STEP 3. Voltage measurement at transfer-ECU connector (+B1 terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Check the voltage between the transfer-ECU connector (+B1 terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 5.
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Go to Step 4.
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STEP 4. Check of short to power supply, short to earth, and open circuit in +B1 line between fusible link and transfer-ECU connector.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
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Repair the connector(s) or wiring harness.
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STEP 5. Retest the system
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Check that the transfer-ECU functions work normally.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
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Replace the transfer-ECU (Refer to ).
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