СИСТЕМА ECD 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 the ECM increases the fuel injection volume to improve driveability during engine idling.

WIRING DIAGRAM

A01DZQEE01

INSPECTION PROCEDURE

When using intelligent tester:

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the A/C switch ON.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / A/C SIG.

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

    NG

    INSPECT ECM (AC1 VOLTAGE) Click here

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

  2. INSPECT ECM (AC1 VOLTAGE)


    1. A01E2VTE54

      Start the engine.

    2. Measure the voltage of the ECM connector.

      Standard voltage
      Tester Connection Connection Specified Condition
      E21-2 (AC1) - Body ground A/C compressor ON Below 1.5 V
      E21-2 (AC1) - Body ground A/C compressor OFF 7.5 to 14 V

    NG

    CHECK WIRE HARNESS (ECM - AIR CONDITIONING AMPLIFIER) Click here

    OK

    REPLACE ECM

  3. CHECK WIRE HARNESS (ECM - AIR CONDITIONING AMPLIFIER)


    1. A01E0T9E09

      Disconnect the A9 A/C amplifier connector.

    2. Disconnect the E21 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      A9-14 (AC1)* - E21-2 (AC1) Below 1 Ω
      E21-2 (AC1) - Body ground 10 kΩ or higher

      Tech Tips

      *: Terminal arrangement Click here.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER

When not using intelligent tester:

PROCEDURE


  1. INSPECT ECM (AC1 VOLTAGE)


    1. A01E2VTE55

      Start the engine.

    2. Measure the voltage of the ECM connector.

      Standard voltage
      Tester Connection Connection Specified Condition
      E21-2 (AC1) - Body ground A/C compressor ON Below 1.5 V
      E21-2 (AC1) - Body ground A/C compressor OFF 7.5 to 14 V

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

    NG

  2. CHECK WIRE HARNESS (ECM - AIR CONDITIONING AMPLIFIER)


    1. A01E0T9E09

      Disconnect the A9 A/C amplifier connector.

    2. Disconnect the E21 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      A9-4 (AC1)* - E21-2 (AC1) Below 1 Ω
      E21-2 (AC1) - Body ground 10 kΩ or higher

      Tech Tips

      *: Terminal arrangement Click here.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER