Low Beam Headlight Circuit [10/2014 - 10/2015]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. Check that the relay operates.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Headlight Relay	Headlight relay (Low beam headlights)	ON/OFF	-

   OK

   Headlight relay operates (Low beam headlights illuminate).

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] )

Result: 

NG 

See step  2

1. Remove the H-LP relay from the engine room relay block and junction block assembly.
2. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Voltage not applied between terminals 1 and 2	10 kΩ or higher
   3 - 5	Voltage applied between terminals 1 and 2	Below 1 Ω

Result: 

NG 

REPLACE H-LP RELAY 

Result: 

OK 

See step  3

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Relay terminal 2 - Body ground	Always	11 to 14 V
   Relay terminal 5 - Body ground	Always	11 to 14 V

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Disconnect the A15*1 or A11*2 headlight assembly LH connector.
2. Disconnect the A41*1 or A38*2 headlight assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   *1
   
   

   Tester Connection	Condition	Specified Condition
   Relay terminal 3 - A15-2 (LO)	Always	Below 1 Ω
   Relay terminal 3 - A41-2 (LO)	Always	Below 1 Ω
   Relay terminal 3 - Body ground	Always	10 kΩ or higher

   *2
   
   

   Tester Connection	Condition	Specified Condition
   Relay terminal 3 - A11-2 (LO)	Always	Below 1 Ω
   Relay terminal 3 - A38-2 (LO)	Always	Below 1 Ω
   Relay terminal 3 - Body ground	Always	10 kΩ or higher

   • *1: for HID Headlight
   • *2: for Halogen Headlight

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Disconnect the 3D instrument panel junction block assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 1 - 3D-12	Always	Below 1 Ω
   Relay terminal 1 - Body ground	Always	10 kΩ or higher

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Remove the instrument panel junction block assembly (Refer to REMOVAL [10/2014 - ] ).
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3D-12 - MB-15 (HRLY)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Instrument Panel Junction Block Assembly)

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

(Refer to REMOVAL [10/2014 - ] )

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )