Daytime Running Light Relay Circuit: Procedure

1. Choose the model to be inspected.

   Result

   Result	Proceed to
   for HID Headlight	A
   for Halogen Headlight	B

B → See step   10 

A: Go to next step 

1. Check the operation of the parking lights.

   OK

   The parking lights operate normally.

NG → See step   17 

OK: Go to next step 

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 daytime running lights illuminate.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Daytime Running Light	Daytime running lights	ON/OFF	-

   OK

   The daytime running lights illuminate.

NG → See step   4 

OK → See step   18 

1. Using a voltmeter, check the signal reading of the engine room junction block assembly. Refer to ON-VEHICLE INSPECTION .

   OK

   Output signal reading is normal.

NG → See step   19 

OK: Go to next step 

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 3D main body ECU (multiplex network body ECU) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1F-6 (DRLS) - 3D-25	Always	Below 1 Ω
   3D-25 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the instrument panel junction block assembly. Refer to REMOVAL .
   Fig 1: Measuring Resistance Of Instrument Panel Junction Block Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3D-25 - MB-25 (DRL)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   20 

OK: Go to next step 

1. Disconnect the 1G engine room junction block assembly connector.
2. Disconnect the A14 headlight assembly LH connector.
3. Disconnect the A42 headlight assembly RH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1G-8 (LDRL) - A14-1 (B)	Always	Below 1 Ω
   1G-8 (LDRL) - A42-1 (B)	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the engine room junction block assembly with a new or known good one. Refer to REMOVAL .
2. Check that the daytime running lights operate normally.

   OK

   The daytime running lights operate normally.

NG → See step   21 

OK → END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE) 

1. Check the operation of the high beam headlights.

   OK

   The high beam headlights operate normally.

NG → See step   17 

OK: Go to next step 

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 daytime running lights illuminate.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Daytime Running Light	Daytime running lights	ON/OFF	-

   OK

   The daytime running lights illuminate.

NG → See step   12 

OK → See step   18 

1. Using a voltmeter, check the signal reading of the engine room junction block assembly. Refer to ON-VEHICLE INSPECTION .

   OK

   Output signal reading is normal.

NG → See step   19 

OK: Go to next step 

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 3D main body ECU (multiplex network body ECU) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1F-14 (DRLS) - 3D-25	Always	Below 1 Ω
   3D-25 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the instrument panel junction block assembly. Refer to REMOVAL .
   Fig 2: Measuring Resistance Of Instrument Panel Junction Block Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3D-25 - MB-25 (DRL)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   20 

OK: Go to next step 

1. Replace the engine room junction block assembly with a new or known good one. Refer to REMOVAL .
2. Check that the daytime running lights operate normally.

   OK

   The daytime running lights operate normally.

NG → See step   21 

OK → END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE)