Code No.U1500
Column ECU LIN timeout/Not equip
caution |
Before replacing the ECU, ensure that the communication
circuit is normal.
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JUDGEMENT CRITERIA
The ETACS-ECU will set diagnosis code No. U1500 when no signals are received from the
column switch (column switch ECU).
PROBABLE CAUSES
- Faulty column switch
- Malfunction of the LIN bus
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STEP 1. Resistance measurement at the column switch connector
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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 column switch connector (earth terminal) and
the 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 body earth line between column switch
connector (earth terminal) 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 the column switch connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the voltage between the column switch connector (power supply terminal)
and the 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, and open circuit in power
supply line between column switch connector and junction block 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. Check of open circuit in LIN line between ETACS-ECU connector
and column switch connector.
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Q.
Is the check result normal?
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Go to Step 6.
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Repair the connector(s) or wiring harness.
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STEP 6. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set in the ETACS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch from LOCK (OFF) position to ON position.
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(3)Check if diagnosis code is set.
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Q.
Is the diagnosis code set?
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Replace the column switch.
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A poor connection, open circuit, or other intermittent malfunctions in the LIN
bus lines between the column switch and the ETACS-ECU (Refer to GROUP 00 -
How to Cope
with Intermittent Malfunction ).
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