Horn Circuit

THEFT DETERRENT: THEFT DETERRENT SYSTEM: Horn Circuit

Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the armed state to the alarm sounding state, the main body ECU turns on the HORN relay, causing the horns to sound at intervals of 0.4 seconds.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (VEHICLE HORN)
(a) Select the Active Test, use Techstream (with CAN VIM) to generate a command, and then check the vehicle horns operation.

Main Body





OK:
Vehicle horns sound and stop.
OK -- REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY (MAIN BODY ECU)
NG -- Continue to next step.

2. CHECK HORN
(a) Press the horn switch and check if the vehicle horns sound.
OK:
Vehicle horns sound.
OK -- REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY (MAIN BODY ECU)
NG -- Continue to next step.

3. INSPECT FUSE (HORN)
(a) Remove the HORN fuse from the engine room junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.

4. CHECK HORN (HORN BATTERY VOLTAGE)




(a) Disconnect the H9 and H10 horn connectors.
(b) Measure the voltage of the wire harness side connectors.
Standard voltage:






OK -- REPLACE HORN
NG -- Continue to next step.

5. CHECK WIRE HARNESS (ENGINE ROOM JUNCTION BLOCK - BATTERY)




(a) Disconnect the 3M junction block connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

6. CHECK WIRE HARNESS (ENGINE ROOM JUNCTION BLOCK - HORN AND BODY GROUND)




(a) Disconnect the 3A, 3K and 3J junction block connectors.
(b) Disconnect the H9 and H10 horn connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

7. CHECK DRIVER SIDE JUNCTION BLOCK ASSEMBLY (OPERATION)




(a) Check that the horns sound.
OK:






OK -- REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY (MAIN BODY ECU)
NG -- Continue to next step.

8. CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK - ENGINE ROOM JUNCTION BLOCK AND BODY GROUND)




(a) Disconnect the 1A and 3A junction block connectors.
(b) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE ENGINE ROOM RELAY BLOCK