2005 Toyota PriusFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. INSPECT ECM (+B VOLTAGE) 
    1. Turn the power switch ON (IG).
    2. Measure the voltage between the specified terminals of the E5 and E7 ECM connectors.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      +B (E7-4) - E1 (E5-28) 9 to 14 V
      Fig 1: Identifying E5 And E7 ECM Connectors Terminals
      G02619678Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See  PROBLEM SYMPTOMS TABLE   ) 
    2. NG: GO TO NEXT STEP 
  2. CHECK HARNESS AND CONNECTOR (ECM-BODY GROUND) 
    1. Disconnect the E5 ECM connector.
    2. Check the resistance between the wire harness side connectors.

      Standard (Check for open): 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      E1 (E5-28) - Body ground Below 1 Ω
    3. Reconnect the ECM connector.
      Fig 2: Identifying ECM Connector Terminals
      G02619679Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: GO TO NEXT STEP 
  3. INSPECT ECM (IGSW VOLTAGE) 
    1. Turn the power switch ON (IG).
    2. Measure the voltage between the specified terminals of the E5 and E6 ECM connectors.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      IGSW (E6-9) - E1 (E5-28) 9 to 14 V
      Fig 3: Identifying E5 And E6 ECM Connectors Terminals
      G02619680Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: Go to step   7 . 
    2. NG: GO TO NEXT STEP 
  4. CHECK FUSE (IGN FUSE) 
    1. Remove the IGN fuse from the driver side J/B.
    2. Check the resistance of the IGN fuse.

      Standard: Below 1 Ω 

    3. Reinstall the IGN fuse.
      Fig 4: Identifying IGN Fuse Location
      G02619681Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE 
    2. OK: GO TO NEXT STEP 
  5. INSPECT INTEGRATION RELAY (IG2 RELAY) 
    1. Remove the integration relay from the engine room R/B.
    2. Inspect the IG2 relay.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      (3K-1) - (3I-4) 10 kΩ or higher
      (3K-1) - (3I-4) Below 1Ω (Apply battery voltage to terminals 3I-2 and 3I-3)
    3. Reinstall the integration relay.
      Fig 5: Inspecting Integration Relay (IG2 Relay)
      G02619682Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE INTEGRATION RELAY 
    2. OK: GO TO NEXT STEP 
  6. CHECK FUSE (AM2 FUSE) 
    1. Remove the AM2 fuse from the engine room R/B.
    2. Check the resistance of the AM2 fuse.

      Standard: Below 1 Ω 

    3. Reinstall the AM2 fuse.
      Fig 6: Identifying AM2 Fuse Location
      G02619683Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE 
    2. OK: GO TO NEXT STEP 

      CHECK AND REPAIR HARNESS AND CONNECTOR (BATTERY - IG2 RELAY, IG2 RELAY - ECM) 

  7. INSPECT ECM (MREL VOLTAGE) 
    1. Turn the power switch ON (IG).
    2. Measure the voltage between the specified terminals of the E5 and E7 ECM connectors.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      MREL (E7-7)-E1 (E5-28) 9 to 14 V
      Fig 7: Identifying E5 And E7 ECM Connectors Terminals
      G02619684Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE ECM (See  ECM (1NZ-FXE)  ) 
    2. OK: GO TO NEXT STEP 
  8. CHECK FUSE (EFI FUSE) 
    1. Remove the EFI fuse from the engine room R/B.
    2. Check the resistance of the EFI fuse.

      Standard: Below 1 Ω 

    3. Reinstall the EFI fuse.
      Fig 8: Identifying EFI Fuse Location
      G02619685Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE 
    2. OK: GO TO NEXT STEP 
  9. INSPECT INTEGRATION RELAY (EFI M RELAY) 
    1. Remove the integration relay from the engine room R/B.
    2. Inspect the EFI M relay.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

      Tester Connection Specified Condition
      (3K-1)- (3I-8) 10 kΩ or higher
      (3K-1)- (3I-8) Below 1 Ω (Apply battery voltage to terminals 3I-6 and 3I-7)
    3. Reinstall the integration relay.
      Fig 9: Inspecting Integration Relay (EFI M Relay)
      G02619686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE INTEGRATION RELAY 
    2. OK: GO TO NEXT STEP 
  10. CHECK HARNESS AND CONNECTOR (EFI M RELAY - ECM, EFI M RELAY - BODY GROUND) 
    1. Check the harness and connectors between the EFI M relay and ECM connector.
      1. Remove the integration relay from the engine room R/B.
      2. Disconnect the E7 ECM connector.
      3. Check the resistance between the wire harness side connectors.

        Standard (Check for open): 

        TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

        Tester Connection Specified Condition
        EFI M relay (3I-6) - MREL (E7-7) Below 1 Ω
        Fig 10: Identifying EFI M Relay Location
        G02619687Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard (Check for short): 

        TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

        Tester Connection Specified Condition
        EFI M relay (3I-6) or MREL (E7-7) - Body ground 10 kΩ or higher
      4. Reinstall the integration relay.
      5. Reconnect the ECM connector.
    2. Check the harness and the connectors between the EFI M relay and the body ground.
      1. Remove the integration relay from the engine room R/B.
      2. Check the resistance between the wire harness side connector and the body ground.
        Fig 11: Identifying E7 ECM Connector Terminals
        G02619688Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard (Check for open): 

        TESTER CONNECTION SPECIFIED CONDITION DESCRIPTION

        Tester Connection Specified Condition
        EFI M relay (3I-7) - Body ground Below 1 Ω
      3. Reinstall the integration relay.
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: GO TO NEXT STEP 

      CHECK AND REPAIR HARNESS AND CONNECTOR (TERMINAL +B OF ECM - BATTERY POSITIVE TERMINAL) 

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.