DYNAMIC RADAR CRUISE CONTROL SYSTEM ECU Power Source Circuit

DESCRIPTION

This circuit provides power to operate the driving support ECU. The driving support ECU determines information about the vehicle in front based on data from the radar sensor, and then decides how much acceleration and/or deceleration is needed to maintain the set distance. The driving support ECU also requests the skid control ECU to apply braking and to sound the buzzer.

WIRING DIAGRAM

A019M2RE04

INSPECTION PROCEDURE

Tech Tips

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK DRIVING SUPPORT ECU (B VOLTAGE)


    1. A019MFKE08
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Driving Support ECU)

      Disconnect the driving support ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C1-30 (B) - Body ground Engine switch on (IG) 11 to 14 V

    3. Reconnect the driving support ECU connector.


    NG

    INSPECT IGNITION RELAY NO. 1 Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - BODY GROUND)


    1. A019MFKE09
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Driving Support ECU)

      Disconnect the driving support ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C1-25 (GND) - Body ground Always Below 1 Ω

    3. Reconnect the driving support ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

  3. INSPECT IGNITION RELAY NO. 1


    1. A019MW3E46

      Remove the IG1 relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 No battery voltage applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the IG1 relay.


    NG

    REPLACE IGNITION RELAY NO. 1

    OK

  4. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - ENGINE ROOM RELAY BLOCK)


    1. A019M5DE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Driving Support ECU)
      *2 Engine Room Relay Block

      Disconnect the driving support ECU connector.

    2. Remove the IG1 relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C1-30 (B) - 3 (IG1 relay) Always Below 1 Ω

    4. Install the IG1 relay.

    5. Reconnect the driving support ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (IG1 RELAY POWER SOURCE CIRCUIT)


    1. A019OS7E01
      Text in Illustration
      *1 Engine Room Relay Block

      Disconnect the IG1 relay from the engine room relay block.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      5 (IG1 relay) - Body ground Always 11 to 14 V

    3. Reconnect the IG1 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (IG1 RELAY - BODY GROUND)


    1. A019OS7E01
      Text in Illustration
      *1 Engine Room Relay Block

      Disconnect the IG1 relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (IG1 relay) - Body ground Always Below 1 Ω

    3. Reconnect the IG1 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR


    1. Disconnect the power management control ECU connector.

      A019M0TE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Management Control ECU)

      		 *2 Engine Room Relay Block

    2. Remove the IG1 relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      1 (IG1 relay terminal) - F8-20 (IG1D) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1 (IG1 relay terminal) - F8-20 (IG1D) - Body ground Always 10 kΩ or higher

    4. Reconnect the power management control ECU connector.

    5. Reinstall the IG1 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    GO TO ENTRY AND START SYSTEM (FOR START FUNCTION) Click here