THEFT DETERRENT SYSTEM Security Horn Circuit

DESCRIPTION

When the theft deterrent system is in the alarm sounding state, the main body ECU outputs a signal repeatedly at 0.4 second intervals, causing the security horn assembly to sound.

WIRING DIAGRAM

A009B8LE05

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SECURITY HORN)


    1. Operate the intelligent tester according to the steps on the display and select Active Test Click here.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Security Horn Security horn ON/OFF -
      OK
      Security horn operates normally.

    NG

    INSPECT S-HORN RELAY Click here

    OK

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

  2. INSPECT S-HORN RELAY


    1. A00951AE01

      Remove the S-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 is not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE S-HORN RELAY

    OK

  3. INSPECT SECURITY HORN ASSEMBLY


    1. Remove the security horn Click here.

    2. Apply battery voltage to the horn connector and check the operation of the horn.

      OK
      Measurement Condition Specified Condition

      Battery positive (+) → Terminal 1

      Battery negative (-) → Horn bracket

      		 Horn sounds

    NG

    REPLACE SECURITY HORN ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - MAIN BODY ECU AND SECURITY HORN)


    1. Remove the S-HORN relay from the engine room relay block.

    2. Remove the main body ECU Click here.

    3. Disconnect the A26 horn connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay block S-HORN relay terminal 1 - A-17 (SH) Always Below 1 Ω
      Relay block S-HORN relay terminal 3 - A26-1 Always Below 1 Ω
      A-17 (SH) - Body ground Always 10 kΩ or higher
      A26-1 - Body ground Always 10 kΩ or higher

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Relay block S-HORN relay terminal 2 - Body ground Always 11 to 14 V
      Relay block S-HORN relay terminal 5 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here