The ETACS-ECU receives signal from the column-ECU. If signal cannot be received at all,
diagnosis code No.U1500 will be set.
COMMENT ON TROUBLE SYMPTOM
The M.U.T.-III shows a diagnosis code status as active.
Connector(s) or wiring harness in the LIN bus lines between the column-ECU and the
ETACS-ECU, the power supply system of the column-ECU, or the column-ECU itself may be defective.
The M.U.T.-III shows a diagnosis code status as stored.
If diagnosis code No.U1500 is stored as a past trouble, carry out diagnosis with
particular emphasis on wiring and connector(s) in the LIN bus line between the column-ECU and
the ETACS-ECU, and the power supply system of the column-ECU. For diagnosis procedures, refer
to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to
Treat Past Trouble .
STEP 2. Resistance measurement at the C-302 column switch connector
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the C-302 column switch connector terminal No. 4 and the
body earth. OK: Continuity exists (2 Ω or less)
Q.
Is the check result normal?
Go to Step 4.
Go to Step 3.
STEP 3. Check the wiring herness between C-302 column switch connector
terminal No. 4 to body earth
Check the earth wires for open circuit.
Q.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/inspection Service Points - How to Cope with Intermittent
Malfunction ).
Repair the wiring harness.
STEP 4. Voltage measurement at the C-302 column switch connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the voltage between the C-302 column switch connector terminal No. 1 and the body
earth. OK: System voltage
Q.
Is the check result normal?
Go to Step 6.
Go to Step 5.
STEP 5. Check the wiring herness between C-302 column switch connector
terminal No. 1 and the C-209 junction block connector terminal No. 2
Check the power supply line for open circuit and short circuit.
note
Prior to the wiring harness inspection, check joint connector C-132, and repair if necessary.
Q.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/inspection Service Points - How to Cope with Intermittent
Malfunction ).
Repair the wiring harness.
STEP 6. Check the wiring harness between C-219 ETACS-ECU connector
terminal No.54 and C-302 column switch connector terminal No.3.
Check the communication line for open circuit.
Q.
Is the check result normal?
Go to Step 7.
Repair the wiring harness. Go to Step 7.
STEP 7. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)On completion, check that the diagnosis code is reset.
Q.
Is the diagnosis code set?
Replace the lighting switch.
A poor connection, open circuit or other intermittent malfunction is present in
the LIN bus lines between the column-ECU and the ETACS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ).
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Go to Step 2.
Repair the defective connector. Go to Step 7.)
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