Horn Circuit

THEFT DETERRENT: THEFT DETERRENT SYSTEM: Horn Circuit
- Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the arming state to the alarm sounding state, the theft warning ECU transmits a signal to cause the horns to sound at intervals of 0.4 seconds.

WIRING DIAGRAM





INSEPCTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (VEHICLE HORN)

(a) Select the Active Test, use the Techstream (with CAN VIM) to generate a control command, and then check that the vehicle horns sound.

Theft Deterrent





OK:

Vehicle horns sound normally.

OK -- REPLACE THEFT WARNING ECU ASSEMBLY
NG -- Continue to next step.

2. CHECK OPERATION (VEHICLE HORN)





(a) Remove the multiplex network front light ECU from the engine room No. 2 relay block.

(b) Using a service wire, short-circuit terminal 1 of the ECU. Then check that the vehicle horns sound.

OK:

Vehicle horns sound normally.

OK -- REPLACE MULTIPLEX NETWORK FRONT LIGHT ECU
NG -- Continue to next step.

3. INSPECT FUSE (HORN)

(a) Remove the HORN fuse from the engine room No. 1 relay block.

(b) Measure the resistance of the fuse.

Standard resistance:

Below 1 Ohms

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

4. INSPECT HORN RELAY

(a) Remove the HORN relay from the engine room No. 2 relay block.





(b) Measure the resistance of the relay.

Standard resistance:





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

5. INSPECT LOW PITCHED HORN ASSEMBLY





(a) Apply battery voltage and check operation of the low pitched horn.

OK:





NG -- REPLACE LOW PITCHED HORN ASSEMBLY
OK -- Continue to next step.

6. INSPECT HIGH PITCHED HORN ASSEMBLY





(a) Apply battery voltage and check operation of the high pitched horn.

OK:





NG -- REPLACE HIGH PITCHED HORN ASSEMBLY
OK -- Continue to next step.

7. CHECK WIRE HARNESS (HORN RELAY - FRONT LIGHT ECU, HORN AND BATTERY)





(a) Remove the horn relay from the engine room No. 2 relay block.

(b) Remove the multiplex network front light ECU from the engine room No. 2 relay block.

(c) Disconnect the H12 and H13 horn connectors.

(d) Measure the resistance and voltage of the wire harness side connectors.

Standard resistance:





Standard voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE