Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: High Beam Headlight Circuit

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Exterior / Lighting (ext) / Lighting System(for Hv Model Without Cornering Light) / High Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the high beam headlights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Check the operation of the low beam headlights. If the low beam headlights do not operate normally, refer to Problem Symptoms Table.

    Click here

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

    Click here

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Main Body > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Head Light Hi

High beam headlights

OFF or ON

-
Body Electrical > Main Body > Active Test

Tester Display

Head Light Hi

OK:

High beam headlights illuminate.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT DIM RELAY

(a) Inspect the DIM relay.

Click here

NG

REPLACE DIM RELAY
OK

3.

CHECK HARNESS AND CONNECTOR (POWER SOURCE - DIM RELAY)

(a) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

1 (DIM relay) - Body ground

Power switch off

11 to 14 V

3 (DIM relay) - Body ground

Power switch off

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (DIM RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) Disconnect the G33 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (DIM relay) - G33-13 (DIM)

Always

Below 1 Ω

2 (DIM relay) or G33-13 (DIM) - Body ground

Always

10 kΩ or higher
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
    Headlight Dimmer Switch Circuit

    How To Proceed With Troubleshooting

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