LIGHTING SYSTEM Low Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the headlight relays located within the integration relay.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the intelligent tester on.

   4. Enter the following menus: Body / Main Body / Active Test.

   5. Check that the relays operate.

      Main Body

      Tester Display	Test Part	Control Range	Diagnostic Note
      Headlight Relay	Headlight relays	ON/OFF	-

      OK
      Headlight relays operate. (Low beam headlights illuminate.)

   
   

   NG

   CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BATTERY AND BODY GROUND) Click here

   OK

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

2. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BATTERY AND BODY GROUND)

   
   

   1. Disconnect the 1H and 1G No. 1 integration relay connectors.

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

      Standard Voltage
      Tester Connector Condition Specified Condition 1H-7 (BATT) - Body ground Always 11 to 14 V 1G-14 (IG1) - Body ground Power switch on (IG) 11 to 14 V

      Standard Resistance
      Tester Connection Condition Specified Condition 1H-3 (GND2) - Body ground Always Below 1 Ω 1G-22 (GND1) - Body ground Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

   
   

   1. Disconnect the 1G No. 1 integration relay connector.

   2. Disconnect the 2C instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1G-9 (HL4) - 2C-32 Always Below 1 Ω 1G-9 (HL4) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

   
   
   1. 

      Text in Illustration

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

      Remove the instrument panel junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 2C-32 - A-15 (HRLY) Always Below 1 Ω 2C-32 - Body ground Always 10 kΩ or higher

   
   

   NG

   REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

   OK

5. REPLACE NO. 1 INTEGRATION RELAY

   
   

   1. Replace the No. 1 integration relay with a new or known good one Click here.

   2. Check that the low beam headlights operate normally.

      OK
      Low beam headlights operate normally.

   
   

   NG

   REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

   OK

   END