AUTOMATIC TRANSAXLE SYSTEM ECU Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, voltage from the MREL terminal of the ECM is applied to the EFI-MAIN NO. 1 relay. This causes the contacts of the EFI-MAIN NO. 1 relay to close, which supplies power to terminal +B of the TCM.

WIRING DIAGRAM

A01QPITE01
*a from EFI-MAIN NO. 1 Fuse
*b EFI-MAIN NO. 1
*c CAN Communication Line

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)


    1. A01QRMUC12
      *a

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B79-8 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT ECU TERMINAL VOLTAGE (+B TERMINAL)


    1. A01QRMUC13
      *a

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B79-18 (+B) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  3. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - TCM)


    1. Remove the EFI-MAIN NO. 1 relay from the engine room relay block and junction block assembly.

    2. Disconnect the B79 TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (EFI-MAIN NO. 1 relay) - B79-18 (+B) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) or B79-18 (+B) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    GO TO ECD SYSTEM (ECM POWER SOURCE CIRCUIT) for 2AD-FTV: Click here for 2AD-FHV: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR