Headlight Leveling ECU Power Source Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / HL Auto Leveling / Data List.
5. Read the display on the Techstream.
   HL AUTO LEVELING
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   +B	IG power supply voltage value / 0 to 20 V	11 to 14 V	-

   OK

   Normal condition listed above is displayed.

NG → See step   2 

OK → See step   5 

1. Disconnect the A48 headlight leveling ECU assembly connector.
   Fig 1: Identifying Headlight Leveling ECU Assembly Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A48-1 (IG) - Body ground	Power switch on (IG)	11 to 14 V
   A48-1 (IG) - Body ground	Power switch off	Below 1 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Headlight Leveling ECU Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying Headlight Leveling ECU Assembly Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A48-9 (E1) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Headlight Leveling ECU Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   4