Headlight Relay Circuit [08/2015 - 08/2019]: Procedure

1. Using the Techstream, perform the Active Test (Refer to DATA LIST / ACTIVE TEST [08/2015 - 08/2016] , or refer to DATA LIST / ACTIVE TEST [08/2016 - 08/2019] ).
   MAIN BODY
   
   

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

   OK

   Headlight relay operates (low beam headlights illuminate).

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

(Refer to REMOVAL [08/2015 - 08/2019] )

Result: 

NG 

See step  2

1. Remove the headlight relay from the engine room relay block.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

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

Result: 

NG 

REPLACE HEADLIGHT RELAY [H-LP LO] 

Result: 

OK 

See step  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the headlight relay from the engine room relay block assembly.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Headlight relay terminal 1 - Body ground	Always	11 to 14 V
   Headlight relay terminal 5 - Body ground

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Headlight Relay)

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Remove the headlight relay from the engine room relay block assembly.
2. Disconnect the 2F driver side junction block assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Headlight relay terminal 2 - 2F-40	Always	Below 1 Ω
   2F-40 - Body ground	Always	10 kΩ or higher

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the driver side junction block assembly (Refer to REMOVAL [08/2015 - 08/2019] ).
2. Remove the main body ECU from the driver side junction block assembly (Refer to REMOVAL [08/2015 - 08/2019] ).
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A-15 (HRLY) - 2F-40	Always	Below 1 Ω

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [08/2015 - 08/2016] , or refer to PROBLEM SYMPTOMS TABLE [08/2016 - 08/2019] )

Result: 

NG 

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY