Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

PERFORM ACTIVE TEST BY INTELLIGENT TESTER (HEADLIGHT RELAY)

Select the ACTIVE TEST, use the intelligent tester (with CAN VIM) to generate a control command, and then check that the headlight illuminates.

Driver side junction block ECU

ACTIVE TEST DETAIL - DRIVER SIDE JUNCTION BLOCK ECU

Item	Test Details	Diagnostic Note
HEAD LIGHT	Headlight relay ON / OFF	-

OK: Headlight illuminates.

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

NG: Go to Next step

INSPECT RELAY (Marking: HEAD LP)

Remove the HEAD LP relay from the engine room No. 1 relay block.

Fig 1: Identifying Head LP Relay Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance of the relay.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
1 - 2	10 kΩ or higher
1 - 2	Below 1Ω (when battery voltage is applied to terminals 3 and 4)

NG: REPLACE RELAY

OK: Go to Next step

CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - BODY GROUND)

Fig 2: Identifying Driver Side Junction Block ECU Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Disconnect the D2 ECU connector.
2. Using a service wire, connect D2-7 (HRLY) on the wire harness side and body ground.
3. Check that the headlight illuminates.
  OK: Headlight illuminates.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE