LEXUS LS430 2003 Factory Repair Manual

LOCATION
Fig. 1: Identifying Horn System Components And Replacements Location

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SYSTEM DIAGRAM
Fig. 2: Identifying Horn System Diagram

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PROBLEM SYMPTOMS TABLE
Fig. 3: Problem Symptoms Table

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INSPECTION
1.INSPECT FUSE (HORN)

a. Check the resistance of the HORN fuse.
Standard: Below 1 ohms
If the result is not as specified, replace the fuse.
Fig. 4: Inspecting Fuse (Horn)

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2.INSPECT HIGH PITCHED HORN ASSY
a. Check operation of the horn.
OK:
HIGH PITCHED HORN ASSY TABLE
Measurement ConditionSpecified Condition
Battery positive (+) --> Terminal 1, Battery negative (-) --> Horn bracketHorn sounds

Fig. 5: Inspecting High Pitched Horn Assy
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If the result is not as specified, replace the horn assy.
3.INSPECT LOW PITCHED HORN ASSY
a. Check operation of the horn.
OK:
LOW PITCHED HORN ASSY TABLE
Measurement ConditionSpecified Condition
Battery positive (+) -> Terminal 1, Battery negative
(-) -> Horn bracketHorn sounds

Fig. 6: Inspecting Low Pitched Horn Assy
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If the result is not as specified, replace the horn assy.
If all the check results are as specified above and the wire harness is normal, replace the horn button
switch (steering wheel pad) (see REPLACEMENT
).
REPLACEMENT
1.REMOVE LOW PITCHED HORN ASSY
a. Disconnect the connector.
b. Remove the bolt and horn.
2.REMOVE HIGH PITCHED HORN ASSY
a. Disconnect the connector.
b. Remove the bolt and horn.

Fig. 7: Removing LO/HIGH Pitched Horn Assy
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3.INSTALL LOW PITCHED HORN ASSY
a. Place the stay onto the baffle part in the radiator support upper, and then install the horn with the
bolt.
Torque: 20 N.m (204 kgf.cm, 15 ft.lbf)
b. Connect the connector.
4.INSTALL HIGH PITCHED HORN ASSY
a. Place the stay onto the baffle part in the radiator support upper, and then install the horn with the
bolt.
Torque: 20 N.m (204 kgf.cm, 15 ft.lbf)
b. Connect the connector.

LOCATION
Fig. 1: Identifying Ignition System Components And Replacement Location

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SYSTEM DIAGRAM
The ECM determines ignition timing based on signals from various sensors.

Fig. 2: Ignition System Diagram (1 Of 2)
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Fig. 3: Ignition System Diagram (2 Of 2)
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ON-VEHICLE INSPECTION
1.INSPECT IGNITION COIL ASSY (WITH IGNITER) AND PERFORM SPARK TEST
a. Check for DTCs.
b. Check if sparks occur.
1. Remove the ignition coil (see REPLACEMENT
).
2. Remove the spark plug.
3. Install the spark plug to the ignition coil, and connect the ignition coil connector.
4. Disconnect the 8 injector connectors.
5. Ground the spark plu
g.

6. Visually check if spark occurs while the engine is being cranked.
If a spark does not occur, perform the test as follows:
Fig. 4: Spark Test Flow Diagram

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7. Using a 16 mm (0.63 in.) plug wrench, install the spark plugs.
Torque: 18 N.m (180 kgf.cm, 13 ft.lbf)
8. Install the ignition coils (see REPLACEMENT
).