Daytime Running Light Circuit [01/2019 - 09/2022]: Procedure

1. Check the operation of the low beam headlights.

   OK

   The low beam headlights operate normally.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [01/2019 - 06/2021]  , or refer to  PROBLEM SYMPTOMS TABLE [06/2021 - 09/2022] 

Result: 

OK 

See step  2

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 / Main Body / Active Test.
5. Perform the Active Test according to the display on the Techstream.

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Daytime Running Light	Daytime running lights	OFF or ON	-

   Body Electrical > Main Body > Active Test 

   Tester Display
   Daytime Running Light

   OK

   Daytime running lights illuminate.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [01/2019 - 06/2021]  , or refer to  PROBLEM SYMPTOMS TABLE [06/2021 - 09/2022] 

Result: 

NG 

See step  3

1. Disconnect the 4B instrument panel junction block assembly connector.
2. Disconnect the A81 headlight assembly LH connector.
3. Disconnect the A80 headlight assembly RH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4B-28 - A81-1 (B)	Always	Below 1 Ω
   4B-28 - A80-1 (B)	Always	Below 1 Ω
   4B-28 or A81-1 (B) - Body ground	Always	10 kΩ or higher
   4B-28 or A80-1 (B) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4B-28 - MB-25 (DRL)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [01/2019 - 03/2019]  , or refer to  REMOVAL [03/2019 - 09/2022] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [01/2019 - 03/2019]  , or refer to  REMOVAL [03/2019 - 09/2022]