Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the armed state to the alarm sounding state, the main body ECU (multiplex network body ECU) transmits a signal to cause the horn to sound at intervals of 0.4 seconds.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
    • for HEV Model:

      Click here

    • for Gasoline Model:

      Click here

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

PROCEDURE

1.

INSPECT HORN

(a) Press the horn switch and check if the horn sounds.

Result

Proceed to

Horn sounds

A

Horn does not sound

B

B

GO TO HORN SYSTEM

A

2.

INSPECT POWER DISTRIBUTION BOX ASSEMBLY

(a) Remove the main body ECU (multiplex network body ECU).

Click here

*a

Component without harness connected

(Power Distribution Box Assembly)

-

-

(b) Disconnect the 8E power distribution box assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

8E-11 - MB-23 (HORN)

Always

Below 1 Ω

NG

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

OK

3.

CHECK HARNESS AND CONNECTOR (HORN RELAY - POWER DISTRIBUTION BOX ASSEMBLY)

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

*1

No. 1 Engine Room Relay Block

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

HORN relay holder terminal 2 - 8E-11

Always

Below 1 Ω

HORN relay holder terminal 2 or 8E-11 - Other terminals and body ground

Always

10 kΩ or higher

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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