SFI SYSTEM Starter Signal Circuit

DESCRIPTION

While the engine is being cranked, current flows from terminal ST1 of the ignition switch*1 or terminal STAR of the power management control ECU*2 to the clutch pedal switch and also flows to terminal STA of the ECM (STA Signal).


WIRING DIAGRAM

A01IRM1E04
A01IQ94E05

INSPECTION PROCEDURE

Note

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

Tech Tips

This chart is based on the premise that the engine can crank normally. If the engine cannot crank normally, proceed to the problem symptoms table Click here.

PROCEDURE


  1. CHECK IF VEHICLE IS EQUIPPED WITH ENTRY AND START SYSTEM


    1. Confirm the entry and start system.

      Result
      Result Proceed to
      w/o Entry and Start System A
      w/ Entry and Start System B

    B

    READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL) Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read the value.

      OK
      Ignition Switch Position Starter Signal
      ON Close (OFF)
      START Open (ON)

    NG

    CHECK ST RELAY (POWER SOURCE) Click here

    OK

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

  3. CHECK ST RELAY (POWER SOURCE)


    1. A01IN0NE01
      Text in Illustration
      *1 No. 3 Relay Block
      *2 ST Relay

      Remove the ST relay from the No. 3 relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      ST relay terminal 1 - Body ground Engine cranking 11 to 14 V

      Tech Tips

      The engine does not crank because the relay is not installed.

    3. Reinstall the ST relay.

      Result
      Result Proceed to
      OK A
      NG B

    B

    CHECK HARNESS AND CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY) Click here

    A

  4. INSPECT ST RELAY


    1. A01IOTM

      Remove the ST relay from the No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage is not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the ST relay.


    NG

    REPLACE ST RELAY

    OK

  5. CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)


    1. A01IN0NE01
      Text in Illustration
      *1 No. 3 Relay Block
      *2 ST Relay

      Remove the ST relay from the No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      ST relay terminal 2 - Body ground Always Below 1 Ω

    3. Reinstall the ST relay.

      Result
      Result Proceed to
      OK A
      NG B

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - BODY GROUND)

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - CLUTCH START SWITCH ASSEMBLY)

  6. CHECK HARNESS AND CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY)


    1. A01IU01E02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Clutch Start Switch Assembly)
      *2 No. 3 Relay Block
      *3 ST Relay

      Remove the ST relay from the No. 3 relay block.

    2. Disconnect the clutch start switch assembly connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      ST relay terminal 1 - A4-1 Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      ST relay terminal 1 or A4-1 - Body ground Always 10 kΩ or higher

    4. Reinstall the ST relay.

    5. Reconnect the clutch start switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY)

    OK

  7. INSPECT CLUTCH START SWITCH ASSEMBLY


    1. Inspect the clutch start switch assembly Click here.


    NG

    REPLACE CLUTCH START SWITCH ASSEMBLY Click here

    OK

  8. CHECK HARNESS AND CONNECTOR (CLUTCH START SWITCH ASSEMBLY - IGNITION SWITCH ASSEMBLY)


    1. A01IRE9E03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Clutch Start Switch Assembly)
      *2

      Front view of wire harness connector

      (to Ignition Switch Assembly)

      Disconnect the clutch start switch assembly connector.

    2. Disconnect the ignition switch assembly connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      A4-2 - H6-1 (ST1) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      A4-2 or H6-1 (ST1) - Body ground Always 10 kΩ or higher

    4. Reconnect the clutch start switch assembly connector.

    5. Reconnect the ignition switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CLUTCH START SWITCH ASSEMBLY - IGNITION SWITCH ASSEMBLY)

    OK

  9. INSPECT IGNITION SWITCH ASSEMBLY


    1. A01IT63E06
      Text in Illustration
      *1

      Component without harness connected

      (Ignition Switch Assembly)

      Disconnect the ignition switch assembly connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      All terminals Off 10 kΩ or higher
      2 (AM1) - 1 (ST1) START Below 1 Ω

    3. Reconnect the ignition switch assembly connector.


    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY)

  10. READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read the value.

      OK
      Ignition Switch Position Starter Signal
      ON Close (OFF)
      START Open (ON)

    NG

    CHECK ST RELAY (POWER SOURCE) Click here

    OK

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

  11. CHECK ST RELAY (POWER SOURCE)


    1. A01IN0NE01
      Text in Illustration
      *1 No. 3 Relay Block
      *2 ST Relay

      Remove the ST relay from the No. 3 relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      ST relay terminal 1 - Body ground Engine cranking 11 to 14 V

      Tech Tips

      The engine does not crank because the relay is not installed.

    3. Reinstall the ST relay.

      Result
      Result Proceed to
      OK A
      NG B

    B

    CHECK HARNESS AND CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY) Click here

    A

  12. INSPECT ST RELAY


    1. A01IOTM

      Remove the ST relay from the No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage is not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the ST relay.


    NG

    REPLACE ST RELAY

    OK

  13. CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)


    1. A01IN0NE01
      Text in Illustration
      *1 No. 3 Relay Block
      *2 ST Relay

      Remove the ST relay from the No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      ST relay terminal 2 - Body ground Always Below 1 Ω

    3. Reinstall the ST relay.

      Result
      Result Proceed to
      OK A
      NG B

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - BODY GROUND)

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - CLUTCH START SWITCH ASSEMBLY)

  14. CHECK HARNESS AND CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY)


    1. A01IU01E02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Clutch Start Switch Assembly)
      *2 No. 3 Relay Block
      *3 ST Relay

      Remove the ST relay from the No. 3 relay block.

    2. Disconnect the clutch start switch assembly connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      ST relay terminal 1 - A4-1 Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      ST relay terminal 1 or A4-1 - Body ground Always 10 kΩ or higher

    4. Reinstall the ST relay.

    5. Reconnect the clutch start switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - CLUTCH START SWITCH ASSEMBLY)

    OK

  15. INSPECT CLUTCH START SWITCH ASSEMBLY


    1. Inspection the clutch start switch assembly Click here.


    NG

    REPLACE CLUTCH START SWITCH ASSEMBLY Click here

    OK

  16. CHECK HARNESS AND CONNECTOR (CLUTCH START SWITCH ASSEMBLY - POWER MANAGEMENT CONTROL ECU)


    1. A01IPBKE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Clutch Start Switch Assembly)
      *2

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the clutch start switch assembly connector.

    2. Disconnect the power management control ECU connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      A4-2 - H70-3 (STAR) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      A4-2 or H70-3 (STAR) - Body ground Always 10 kΩ or higher

    4. Reconnect the clutch start switch assembly connector.

    5. Reconnect the power management control ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CLUTCH START SWITCH ASSEMBLY - POWER MANAGEMENT CONTROL ECU)

    OK

    GO TO ENTRY AND START SYSTEM Click here