Headlight Leveling ECU Power Source Circuit: Procedure

WARNING: This page is about a different car, the 2011 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT IGNITION RELAY NO. 1

Inspect IG1 relay continuity.

Fig 1: Identifying IG1 Relay Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Remove the IG1 relay from the instrument panel J/B.

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

Standard resistance

Tester Connection	Specified Condition
3 - 5	10 kΩ or higher
3 - 5	Below 1 Ω (When battery voltage is applied to terminal 1 - 2)

NG → REPLACE IGNITION RELAY NO. 1

OK: Go to next step

INSPECT HEADLIGHT BEAM LEVEL CONTROL ECU

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

Fig 2: Identifying Headlight Beam Level Control ECU Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard voltage

Tester Connection	Condition	Specified Condition
A21-14 - A21-1	Ignition switch off → Ignition switch on (IG)	Below 1 V → 10 to 14 V

NG → See step 3

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

CHECK HARNESS AND CONNECTOR (BATTERY - HEADLIGHT BEAM LEVEL CONTROL ECU)

Disconnect connector A21 of the headlight beam level control ECU.