ECD SYSTEM Air Conditioning Signal Circuit

DESCRIPTION

When the A/C compressor is on, the A/C amplifier sends the A/C signal to the ECM, then ECM increases the fuel injection volume to improve driveability during engine idling.

WIRING DIAGRAM

A01BG9WE01

INSPECTION PROCEDURE

When using intelligent tester:

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (AIR CONDITIONER SIGNAL)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Air conditioning switch on.

    4. Select the item "Powertrain/Engine and ECT/Data List/A/C Signal" and read its value displayed on the intelligent tester.

      Result
      A/C Compressor Display
      OFF A/C Signal OFF
      ON A/C Signal ON

    NG

    INSPECT ECM (CHECK VOLTAGE) Click here

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

  2. INSPECT ECM (CHECK VOLTAGE)


    1. A01BCNHE16

      Start the engine.

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

      Standard voltage
      Tester Connection Connection Specified Condition
      AC1 (B8-2) - Body ground A/C compressor ON Below 1.5 V
      AC1 (B8-2) - Body ground A/C compressor OFF 7.5 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONER AMPLIFIER) Click here

    OK

    REPLACE ECM

  3. CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONER AMPLIFIER)


    1. A01BD1TE02

      Disconnect the A/C amplifier H19 connector.

    2. Disconnect the ECM B8 connector.

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

      Standard resistance (Check for open)
      Tester Connection Specified Condition

      AC1 (H19-8) (*1) - AC1 (B8-2)

      		 Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      AC1 (B8-2) - Body ground 10 kΩ or higher

      Tech Tips

      *1: Terminal arrangement Click here.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONER AMPLIFIER

When not using intelligent tester:

PROCEDURE


  1. INSPECT ECM (CHECK VOLTAGE)


    1. A01BCNHE16

      Start the engine.

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

      Standard voltage
      Tester Connection Connection Specified Condition
      AC1 (B8-2) - Body ground A/C compressor ON Below 1.5 V
      AC1 (B8-2) - Body ground A/C compressor OFF 7.5 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONER AMPLIFIER) Click here

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

  2. CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONER AMPLIFIER)


    1. A01BD1TE02

      Disconnect the A/C amplifier H19 connector.

    2. Disconnect the ECM B8 connector.

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

      Standard resistance (Check for open)
      Tester Connection Specified Condition

      AC1 (H19-8) (*1) - AC1 (B8-2)

      		 Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      AC1 (B8-2) - Body ground 10 kΩ or higher

      Tech Tips

      *1: Terminal arrangement Click here.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONER AMPLIFIER