Theft Warning Siren Circuit

DESCRIPTION

The theft warning siren has an internal battery. If any of the vehicle's battery or communication line is opened, the theft warning siren detects it by itself and sounds. Although the theft warning siren sounds by receiving a signal from the multiplex network body ECU usually, the theft warning siren can sound by its internal battery in case that the circuit of the vehicle's battery is opened.
The multiplex network body ECU sends an arming signal to the theft warning siren while transferring to the Armed State, and it also sounds a disarming signal to the siren while switching to the Disarmed State. Besides, the multiplex network body ECU can cause the theft warning siren to sound by sending an alarm signal during the Alarm Sounding State.

WIRING DIAGRAM

INSPECTION PROCEDURE

1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch ON.

3. Turn the intelligent tester main switch on.

4. Select the item below in the ACTIVE TEST and then check that the horn operate.

   BODY (Multiplex network body ECU): 

   Item	Test Details	Diagnostic Note
   Security Horn	Security horn (theft warning siren) ON/OFF	-

   OK:

   The theft warning siren sounds or stops correctly when operating it through the intelligent tester.
   

NG	Go to step 2

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN THE PROBLEM SYMPTOMS TABLE

2. INSPECT FUSE (FUEL OPN)

1. Remove the FUEL OPN fuse from the instrument panel J/B.

2. Measure the resistance.

   Resistance:

   Below 1 Ω
   

NG	REPLACE FUSE

OK

3. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B ASSEMBLY - BATTERY)

1. Install the FUEL OPN fuse to instrument panel J/B.

2. Disconnect the 1A connector.

3. Measure the voltage according to the value(s) in the table below.

   Voltage:

   Tester Connection	Condition	Specified Condition
   1A-1 - Body ground	Always	10 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B ASSEMBLY - THEFT WARNING SIREN ASSEMBLY)

1. Disconnect the 1J connector and T18 siren connector.

2. Measure the resistance according to the value(s) in the table below.

   Resistance:

   Symbol (Tester Connection)	Specified Condition
   1J-6 - +B (T18-1)	Below 1 Ω
   1J-6 or +B (T18-1) - Body ground	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5. CHECK THEFT WARNING SIREN ASSEMBLY

1. Reconnect 1A and 1J J/B connectors, and T18 siren connector.

2. Measure the voltage according to the value(s) in the table below.

   Voltage:

   Symbol (Tester Connection)	Condition	Specified Condition
   +B (T18-1) - Body ground	Always	10 to 14 V
   GND (T18-2) - Body ground	Always	Below 1 V
   CONT (T18-3) - Body ground	When switched from armed state or arming preparation state to disarmed state (1)	Pulse generation*1 (Using an oscilloscope)
   	When switched from arming preparation state to armed state (2)	Pulse generation*2 (Using an oscilloscope)
   	Normal condition (Except (1) and (2))	Approx. 1.4 V

3. Wave pattern (^*1, ^*2)
   

NG	REPLACE THEFT WARNING SIREN ASSEMBLY

OK

6. CHECK HARNESS AND CONNECTOR (MULTIPLEX NETWORK BODY ECU - THEFT WARNING SIREN ASSEMBLY)

1. Disconnect the B7 ECU connector and T18 siren connector.

2. Measure the resistance according to the value(s) in the table below.

   Resistance:

   Symbol (Tester Connection)	Specified Condition
   SSCL (B7-12) - CONT (T18-3)	Below 1 Ω

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7. CHECK HARNESS AND CONNECTOR (THEFT WARNING SIREN ASSEMBLY - BODY GROUND)

1. Disconnect T18 siren connector.

2. Measure the resistance according to the value(s) in the table below.

   Resistance:

   Symbol (Tester Connection)	Specified Condition
   GND (T18-2) - Body ground	Below 1 Ω

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE INSTRUMENT PANEL J/B ASSEMBLY