STOP AND START SYSTEM STA Signal Circuit

DESCRIPTION

While the engine is being cranked, a starter operation request signal is sent to terminal STA of the ECM.

Tech Tips

If there is an open in the STA circuit of the ECM, stop and start control will be prohibited after the third time the engine is started by stop and start control.


  • Stop and start control will be prohibited until the ignition switch is turned off.

  • The MIL will not illuminate.

  • If there is an open in the STA circuit of the ECM, the engine can still be started using the ignition switch, as the ECM also receives the starter operation request signal from the engine stop and start ECU via CAN communication. (Stop and start control is prohibited as the reliability of the signal sent via CAN communication cannot be assured while the voltage drops during operation of the starter assembly.)

A01TCWPE02

WIRING DIAGRAM

A01TC24E01

PROCEDURE


  1. READ VALUE USING GTS (STARTER SIGNAL)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Starter Signal.


      Powertrain > Engine and ECT > Data List
      Tester Display
      Starter Signal

    5. Read the values displayed on the GTS when the ignition switch is to ON and to START.

      OK
      Tester Display Condition Normal Condition
      Starter Signal Ignition switch ON OFF
      Ignition switch START ON
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  2. CHECK HARNESS AND CONNECTOR (ECM - ST NO. 1 RELAY)


    1. Disconnect the A9 engine stop and start ECU connector.

    2. Disconnect the A173*1, A169*2, A101*3 or A50*4 ECM connector.


      • *1: for 8NR-FTS

      • *2: for 1ND-TV w/ Glow Plug Controller

      • *3: for 1ND-TV w/o Glow Plug Controller

      • *4: for 1WW

    3. Remove the ST NO. 1 relay from engine room relay block and junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A173-24 (STA) - ST NO. 1 relay terminal 2*1 Always Below 1 Ω
      A169-53 (STA) - ST NO. 1 relay terminal 2*2 Always Below 1 Ω
      A101-6 (STA) - ST NO. 1 relay terminal 2*3 Always Below 1 Ω
      A50-36 (STA) - ST NO. 1 relay terminal 2*4 Always Below 1 Ω

      • *1: for 8NR-FTS

      • *2: for 1ND-TV w/ Glow Plug Controller

      • *3: for 1ND-TV w/o Glow Plug Controller

      • *4: for 1WW

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR