Diesel Data: Automotive Repair

Security Horn Circuit








THEFT DETERRENT SYSTEM: Security Horn Circuit

Security Horn Circuit

DESCRIPTION

When the theft deterrent system is operating, a relay in the multiplex network body ECU turns ON and OFF continuously at 0.2 second intervals, causing the security horn to sound.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT SECURITY HORN ASSEMBLY





(a) Apply battery voltage to the horn and check operation of the horn.
Standard:





NG -- REPLACE SECURITY HORN ASSEMBLY
OK -- Continue to next step.
2. CHECK WIRE HARNESS (MULTIPLEX NETWORK BODY ECU - SECURITY HORN ASSEMBLY)





(a) Disconnect the B9 ECU connector.
(b) Disconnect the T1 horn connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE MULTIPLEX NETWORK BODY ECU