Theft Warning Siren Circuit

DESCRIPTION

The theft warning siren (self power siren) has an internal battery. If the vehicle battery cable is disconnected or any of the communication lines are open, the theft warning siren (self power siren) detects this and sounds its siren.
Although the theft warning siren (self power siren) usually sounds by receiving a signal from the main body ECU (instrument panel junction block), the theft warning siren (self power siren) can sound by its internal battery in case the vehicle battery cable is disconnected.
The main body ECU (instrument panel junction block) sends an arming signal to the theft warning siren (self power siren) while transferring to the armed state, and it also sends a disarming signal to the siren while switching to the disarmed state. Also, the main body ECU (instrument panel junction block) can cause the theft warning siren (self power siren) to sound by sending an alarm signal during the alarm sounding state.

WIRING DIAGRAM

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (THEFT WARNING SIREN [SELF POWER SIREN])

Operate the intelligent tester according to the steps on the display and select "Active Test".

Main Body
Tester Display	Test Part	Control Range	Diagnostic Note
Security Horn2	Theft warning siren (self power siren)	ON / OFF	-

OK
Siren operates normally.

NG

CHECK THEFT WARNING SIREN (SELF POWER SIREN) Click here

OK

REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)

CHECK THEFT WARNING SIREN (SELF POWER SIREN)

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

Standard Voltage

Tester Connection	Condition	Specified Condition
H15-1 (+B) - Body ground	Always	11 to 14 V
H15-2 (GND) - Body ground	Always	Below 1 V
H15-3 (CONT) - Body ground	Switched from armed state or arming preparation state to disarmed state (1)	Wave pattern (1) shown in chart below
	Switched from arming preparation state to armed state (2)	Wave pattern (2) shown in chart below
	Normal condition (Except (1) and (2))	1 to 2 V

Result
Result	Proceed to
OK (for Sedan)	A
OK (for Wagon)	B
NG	C

B

REPLACE THEFT WARNING SIREN (SELF POWER SIREN) Click here

C

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU [INSTRUMENT PANEL JUNCTION BLOCK] - THEFT WARNING SIREN [SELF POWER SIREN]) Click here

A

REPLACE THEFT WARNING SIREN (SELF POWER SIREN) Click here

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU [INSTRUMENT PANEL JUNCTION BLOCK] - THEFT WARNING SIREN [SELF POWER SIREN])

Text in Illustration
*1	Front view of wire harness connector (to Main Body ECU [Instrument Panel Junction Block])
*2	Front view of wire harness connector (to Theft Warning Siren [Self Power Siren])

Disconnect the D80 ECU connector.
Disconnect the H15 siren connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
D80-6 (SSCL) - H15-3 (CONT)	Always	Below 1 Ω
D80-6 (SSCL) or H15-3 (CONT) - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

CHECK HARNESS AND CONNECTOR (THEFT WARNING SIREN [SELF POWER SIREN] - BODY GROUND)

Text in Illustration
*1	Front view of wire harness connector (to Theft Warning Siren [Self Power Siren])

Disconnect the H15 siren connector.