Code No.U1006
Security alarm siren LIN timeout <Vehicles with security alarm sensor>
caution
Before replacing the ECU, ensure that the communication
circuit is normal.
JUDGEMENT CRITERIA
The ETACS-ECU will set diagnosis code No. U1006 when no signals are received from the
security alarm siren.
PROBABLE CAUSES
Faulty security alarm siren
Faulty LIN cutoff control unit
Malfunction of the LIN bus
DIAGNOSIS PROCEDURE
STEP 1. Resistance measurement at the security alarm siren
connector
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the security alarm siren connector (earth terminal)
and the body earth. OK: Continuity exists (2 Ω or less)
Q.
Is the check result normal?
Go to Step 3.
Go to Step 2.
STEP 2. Check of open circuit in body earth line between security
alarm siren connector (earth terminal) and the body earth.
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 connector(s) or wiring harness.
STEP 3. Voltage measurement at the security alarm siren connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the voltage between the security alarm siren connector (LITI terminal)
and the body earth. OK: System voltage
Q.
Is the check result normal?
Go to Step 5.
Go to Step 4.
STEP 4. Check of short to power supply, short to earth, and open circuit
in LITI line between ETACS-ECU connector and security alarm siren connector.
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 connector(s) or wiring harness.
STEP 5. Check of open circuit in BUP4 line between ETACS-ECU connector
and security alarm siren connector.
Q.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
STEP 6. Replace the security alarm siren temporarily, and check whether
the diagnosis code is set.
Check again if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if diagnosis code is set.
Q.
Is the diagnosis code set?
Replace the security alarm siren.
A poor connection, open circuit, or other intermittent malfunctions in the LIN
bus lines between the security alarm sensor and the ETACS-ECU (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction ).