LIGHTING SYSTEM Daytime Running Light Relay Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the daytime running lights (low-intensity high beam headlights) via the engine room junction block assembly.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK OPERATION (HIGH BEAM HEADLIGHTS)

   
   

   1. Check the operation of the high beam headlights.

      OK
      The high beam headlights operate normally.

   
   

   NG

   GO TO PROBLEM SYMPTOMS TABLE

   OK

2. PERFORM ACTIVE TEST USING TECHSTREAM

   
   

   1. Connect the Techstream to the DLC3.

   2. Turn the ignition switch to ON.

   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

   CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY Click here

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

3. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY

   
   

   1. Using a voltmeter, check the signal reading of the engine room junction block assembly Click here.

      OK
      Output signal reading is normal.

   
   

   NG

   INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) Click here

   OK

4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE AND BODY GROUND)

   
   

   1. Remove the engine room junction block assembly from the engine room relay block and junction block assembly Click here.

      

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

      Standard Voltage
      Tester Connection Condition Specified Condition A-1 (BATT) - Body ground Always 11 to 14 V B-1 (ALT) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1F-3 (GND1) - Body ground Always Below 1 Ω 1G-4 (GND2) - Body ground Always Below 1 Ω

      Text in Illustration

      *a

      Component without engine room junction block assembly (Engine Room Relay Block and Junction Block Assembly)

      -

      -

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

   
   

   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 - 3D-23 Always Below 1 Ω 3D-23 - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

   
   

   1. Remove the instrument panel junction block assembly Click here.

   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-23 - MB-25 (DRL) Always Below 1 Ω

   
   

   NG

   REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

   OK

7. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY

   
   

   1. Replace the engine room junction block assembly with a new or a known good one Click here.

   2. Check that the daytime running lights operate normally.

      OK
      The daytime running lights operate normally.

   
   

   NG

   REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

   OK

   END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE)