Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Check horn using LEXUS hand-held tester.
PREPARATION:

Connect the LEXUS hand-held tester to the DLC3.

CHECK:

Check the horn using ACTIVE LIST.
1. OK : Proceed to next circuit inspection shown on problem symptom table (See PROBLEM SYMPTOMS TABLE ).
2. NG : Go to next step.
Check HORN fuse.
CHECK:

Check continuity of HORN fuse.

OK:

Continuity
1. NG : Replace the failure fuse.
2. OK : Go to next step.
Check voltage between terminal FHOR and E of front light ECU connector.
PREPARATION:
1. Turn the ignition switch OFF.
2. Disconnect the front light ECU connector.
CHECK:

Measure voltage between terminal FHOR and E.

OK:

Voltage: 10 - 14 V
1. OK : Proceed to next circuit inspection shown on problem symptoms table (See PROBLEM SYMPTOMS TABLE ).
2. NG : Go to next step.
Check horn (See INSPECTION ).
1. NG : Replace horn.
2. OK : Go to next step.
Check wire harness and connector between horn and front light ECU (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
1. NG : Repair or replace wire harness or connector.
2. OK : Proceed to next circuit inspection shown on problem symptoms table (See PROBLEM SYMPTOMS TABLE ).