THEFT DETERRENT SYSTEM (w/ Smart Entry and Start System) Security Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the armed state to the alarm sounding state, the main body ECU (driver side junction block assembly) controls the security horn.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the engine switch on (IG).

   3. Turn the GTS on.

   4. Select the item below in the Active Test and then check that the security horn assembly operates.

      Main Body

      Tester Display	Test Part	Control Range	Diagnostic Note
      Security Horn	Security horn	ON/OFF	-

      OK
      The security horn assembly sounds and stops correctly when operated through the GTS.

   
   

   NG

   INSPECT SECURITY HORN ASSEMBLY Click here

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

2. INSPECT SECURITY HORN ASSEMBLY

   
   

   1. 

      Remove the security horn assembly Click here.

   2. Check the operation of the security horn assembly.

      OK
      Measurement Condition Specified Condition Battery positive (+) → Terminal 1 Horn sounds Battery negative (-) → Horn body

   
   

   NG

   REPLACE SECURITY HORN ASSEMBLY Click here

   OK

3. INSPECT SEC HORN RELAY

   
   

   1. 

      Remove the SEC HORN relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 Ω 3 - 5 Battery voltage not applied between terminals 1 and 2 10 kΩ or higher

   
   

   NG

   REPLACE SEC HORN RELAY

   OK

4. CHECK HARNESS AND CONNECTOR (SEC HORN RELAY POWER SOURCE)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block
      *2	SEC HORN Relay Terminal

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

      Standard Voltage
      Tester Connection Condition Specified Condition Engine room relay block SEC HORN relay terminal 1 - Body ground Always 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. CHECK HARNESS AND CONNECTOR (SEC HORN RELAY - MAIN BODY ECU)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block
      *2	SEC HORN Relay Terminal
      *3	Front view of wire harness connector (to Main Body ECU (Driver Side Junction Block Assembly))

      Disconnect the D51 main body ECU (driver side junction block assembly) connector.

   2. Measure the resistance on the relay block side according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Engine room relay block SEC HORN relay terminal 1 - D51-6 (SH) Always Below 1 Ω Engine room relay block SEC HORN relay terminal 1 - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK HARNESS AND CONNECTOR (SEC HORN RELAY POWER SOURCE)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block
      *2	SEC HORN Relay Terminal

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

      Standard Voltage
      Tester Connection Condition Specified Condition Engine room relay block SEC HORN relay terminal 3 - Body ground Always 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. CHECK HARNESS AND CONNECTOR (SEC HORN RELAY - SECURITY HORN ASSEMBLY)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block
      *2	SEC HORN Relay Terminal
      *3	Front view of wire harness connector (to Security Horn Assembly)

      Disconnect the A23 security horn assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Engine room relay block SEC HORN relay terminal 5 - A23-1 Always Below 1 Ω Engine room relay block SEC HORN relay terminal 5 - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY) Click here