Inspection Procedure
1: The ignition switch (ACC) signal is not received.
caution
Before
replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication
circuit are normal.
When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition
key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine
cannot be started. Register the encrypted code as described in Immobilizer System - How
to Register Key ID .)
COMMENTS ON TROUBLE SYMPTOM
If there is an error to the input signal (ACC) from the ignition switch <Vehicles
without KOS> or OSS-ECU <Vehicles with one touch start system>, or
if the ACC relay in ETACS-ECU does not function normally, the ignition switch (ACC) signal is
no longer output to the communication line.
PROBABLE CAUSES
Malfunction of the ETACS-ECU
Malfunction of the ignition switch <Vehicles without KOS>
Malfunction of the OSS-ECU <Vehicles with one touch start system>
Damaged harness wires and connectors
DIAGNOSIS PROCEDURE
STEP 1. Voltage measurement at ETACS-ECU connector (ACC
terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the "ACC" position.
(3)Check the voltage between the ETACS-ECU connector (ACC terminal) and body earth. OK: System voltage
Q.
Is the check result normal?
Go to Step 5.
NO <vehicles with one touch start system> : Go to Step 2.
NO <vehicles without one touch start system> : Go to Step 3.
STEP 2. Check the M.U.T.-III Diagnosis code for other systems
Check that the OSS-ECU set a diagnosis code.
Q.
Is the diagnosis code set?
Diagnose the OSS-ECU. Refer to GROUP 42B, Troubleshooting .
Go to Step 4.
STEP 3. Ignition switch check
Check the ignition switch. Refer to .
Q.
Is the check result normal?
Go to Step 4.
Troubleshoot the ignition switch. Refer to Inspection Procedure 2 "Malfunction
of the ignition switch power supply system" .
STEP 4. Check of short to power supply, short to earth, and open circuit
in ACC line between ignition switch (ACC) <Vehicles without KOS> or OSS-ECU
(ACC) <Vehicles with one touch start system> and ETACS-ECU connector.
Q.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
STEP 5. M.U.T.-III data list
Check the input signals from the ignition switch (ACC).
Turn the ignition switch to the ACC position.
Item No.
Item name
Normal condition
Item 288
ACC switch
ON
OK: Normal condition is displayed.
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 ).
.)
