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ECM Power Source Circuit: Procedure

  1. INSPECT ECM (POWER SOURCE VOLTAGE) 
    Fig 1: Inspecting ECM (Power Source Voltage)
    GTY387571Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A34-6 (+B) - A36-4 (E01) Ignition switch ON 12 to 14 V
      A33-1 (+B2) - A36-4 (E01) Ignition switch ON 12 to 14 V
      TEXT IN ILLUSTRATION

      *a Component with harness connected
      (ECM)

    NG → See step   4 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A36-4 (E01) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. INSPECT ECM (IGSW TERMINAL VOLTAGE) 
    Fig 2: Inspecting ECM (IGSW Terminal Voltage)
    GTY387570Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A33-27 (IGSW) - A36-4 (E01) Ignition switch ON 10 to 13 V
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (ECM)

    NG → See step   8 

    OK → See step   13 

  4. INSPECT ECM (SSHUT TERMINAL VOLTAGE) 
    Fig 3: Inspecting ECM (SSHUT Terminal Voltage)
    GTY387569Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A35-13 (SSHUT) - A36-4 (E01) Ignition switch ON approximately 0 V
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (ECM)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. INSPECT RELAY (EFI MAIN1) 
    1. Inspect the EFI MAIN1 relay. Refer to ON-VEHICLE INSPECTION [03/2012 - ] - Step 1 .

    NG → REPLACE RELAY (EFI MAIN1) 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (EFI MAIN1 RELAY - ECM) 
    1. Remove the EFI MAIN1 relay from the engine room relay block assembly.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 1 - A35-13 (SSHUT) Always Below 1 Ω
      EFI MAIN1 relay terminal 3 - A34-6 (+B) Always Below 1 Ω
      EFI MAIN1 relay terminal 3 - A33-1 (+B2) Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 1 or A35-13 (SSHUT) - Body ground Always 10 kΩ or higher
      EFI MAIN1 relay terminal 3, A34-6 (+B) or A33-1 (+B2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. INSPECT TERMINAL VOLTAGE (EFI MAIN1 RELAY) 
    1. Remove the EFI MAIN1 relay from the engine room relay block assembly.
      Fig 4: Inspecting Terminal Voltage (EFI MAIN1 Relay)
      GTY388847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 2 - Body ground Always 11 to 14 V
      EFI MAIN1 relay terminal 5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block Assembly
      *2 EFI MAIN1 Relay Terminal

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM) 
    1. Remove the IG2 relay from the engine room relay block assembly.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 - A33-27 (IGSW) Always Below 1 Ω
      IG2 relay terminal 1 - Body ground Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 or A33-27 (IGSW) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. INSPECT RELAY (IG2) 
    1. Inspect the IG2 relay. Refer to ON-VEHICLE INSPECTION [03/2012 - ] - Step 4 .

    NG → REPLACE RELAY (IG2) 

    OK: Go to next step 

  10. INSPECT TERMINAL VOLTAGE (IG2 RELAY) 
    1. Remove the IG2 relay from the engine room relay block assembly.
      Fig 5: Inspecting Terminal Voltage (IG2 Relay)
      GTY388321Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IG2 relay terminal 5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block Assembly
      *2 IG2 Relay Terminal

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (IG2 RELAY - IGNITION OR STARTER SWITCH ASSEMBLY) 
    1. Remove the IG2 relay from the engine room relay block assembly.
    2. Disconnect the ignition or starter 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
      IG2 relay terminal 2 - D55-6 (IG2) Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 2 or D55-6 (IG2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  12. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly. Refer to INSPECTION [03/2012 - ] .

    NG → See step   14 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. REPLACE ECM. Refer to  REMOVAL [03/2012 - 05/2013] 
  14. REPLACE IGNITION OR STARTER SWITCH ASSEMBLY. Refer to  REMOVAL [03/2012 - ] 


  1. INSPECT ECM (POWER SOURCE VOLTAGE) 
    Fig 1: Inspecting ECM (Power Source Voltage)
    GTY387581Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A34-6 (+B) - A36-4 (E01) Ignition switch ON 12 to 14 V
      A33-1 (+B2) - A36-4 (E01) Ignition switch ON 12 to 14 V
      TEXT IN ILLUSTRATION

      *a Component with harness connected
      (ECM)

    NG → See step   4 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A36-4 (E01) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. INSPECT ECM (IGSW TERMINAL VOLTAGE) 
    Fig 2: Inspecting ECM (IGSW Terminal Voltage)
    GTY387580Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A33-27 (IGSW) - A36-4 (E01) Ignition switch ON 10 to 13 V
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (ECM)

    NG → See step   8 

    OK → See step   14 

  4. INSPECT ECM (SSHUT TERMINAL VOLTAGE) 
    Fig 3: Inspecting ECM (SSHUT Terminal Voltage)
    GTY392239Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A35-13 (SSHUT) - A36-4 (E01) Ignition switch ON approximately 0 V
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (ECM)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. INSPECT RELAY (EFI MAIN1) 
    1. Inspect the EFI MAIN1 relay. Refer to ON-VEHICLE INSPECTION [03/2012 - ] - Step 1 .

    NG → REPLACE RELAY (EFI MAIN1) 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (EFI MAIN1 RELAY - ECM) 
    1. Remove the EFI MAIN1 relay from the engine room relay block assembly.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 1 - A35-13 (SSHUT) Always Below 1 Ω
      EFI MAIN1 relay terminal 3 - A34-6 (+B) Always Below 1 Ω
      EFI MAIN1 relay terminal 3 - A33-1 (+B2) Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 1 or A35-13 (SSHUT) - Body ground Always 10 kΩ or higher
      EFI MAIN1 relay terminal 3, A34-6 (+B) or A33-1 (+B2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. INSPECT TERMINAL VOLTAGE (EFI MAIN1 RELAY) 
    1. Remove the EFI MAIN1 relay from the engine room relay block assembly.
      Fig 4: Inspecting Terminal Voltage (EFI MAIN1 Relay)
      GTY388847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      EFI MAIN1 relay terminal 2 - Body ground Always 11 to 14 V
      EFI MAIN1 relay terminal 5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block Assembly
      *2 EFI MAIN1 Relay Terminal

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM) 
    1. Remove the IG2 relay from the engine room relay block assembly.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 - A33-27 (IGSW) Always Below 1 Ω
      IG2 relay terminal 1 - Body ground Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 or A33-27 (IGSW) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. INSPECT RELAY (IG2) 
    1. Inspect the IG2 relay. Refer to ON-VEHICLE INSPECTION [03/2012 - ] - Step 4 .

    NG → REPLACE RELAY (IG2) 

    OK: Go to next step 

  10. INSPECT TERMINAL VOLTAGE (IG2 RELAY) 
    1. Remove the IG2 relay from the engine room relay block assembly.
      Fig 5: Inspecting Terminal Voltage (IG2 Relay)
      GTY388321Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IG2 relay terminal 5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block Assembly
      *2 IG2 Relay Terminal
      RESULT

      Result Proceed to
      NG A
      OK (w/ Smart Key System) B
      OK (w/o Smart Key System) C

    B → See step   11 

    C → See step   12 

    A → REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK HARNESS AND CONNECTOR (IG2 RELAY - CERTIFICATION ECU) 
    1. Remove the IG2 relay from the engine room relay block assembly.
    2. Disconnect the certification ECU (smart key ECU 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
      IG2 relay terminal 2 - D48-9 (IG2D) Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 2 or D48-9 (IG2D) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   16 

  12. CHECK HARNESS AND CONNECTOR (IG2 RELAY - IGNITION OR STARTER SWITCH ASSEMBLY) 
    1. Remove the IG2 relay from the engine room relay block assembly.
    2. Disconnect the ignition or starter 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
      IG2 relay terminal 2 - D55-6 (IG2) Always Below 1 Ω

      Standard Resistance (Check for short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 2 or D55-6 (IG2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  13. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly. Refer to INSPECTION [03/2012 - ] .

    NG → See step   15 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR 

  14. REPLACE ECM. Refer to  REMOVAL [05/2013 - ] 
  15. REPLACE IGNITION OR STARTER SWITCH ASSEMBLY. Refer to  REMOVAL [03/2012 - ] 
  16. GO TO SMART KEY SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2013 - ] 
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