THEFT DETERRENT SYSTEM 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 horns to sound.

WIRING DIAGRAM

*1	HORN
*2	No. 1 Integration Relay (Horn Relay)
*3	Main Body ECU (Multiplex Network Body ECU)

PROCEDURE

1. CHECK HORN OPERATION

   
   

   1. Press the horn switch and check if the horns sound.

      OK
      Horns operate normally.

   
   

   NG

   GO TO HORN SYSTEM Click here

   OK

2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VEHICLE 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
      Vehicle Horn	Vehicle horns	ON/OFF	-

      OK
      Horns operate normally.

   
   

   OK

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

   NG

3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - MAIN BODY ECU)

   
   

   1. Disconnect the 1A relay connector.

   2. Remove the main body ECU Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1A-7 - A-28 (HORN) Always Below 1 Ω 1A-7 or A-28 (HORN) - Body ground Always 10 kΩ or higher

   
   

   OK

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

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR