2008 Toyota Prius BaseFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK MIL CONDITION 
    1. Perform troubleshooting in accordance with the chart below.

      Result 

      RESULT CHART

      Condition Proceed to
      MIL remains ON A
      MIL does not illuminate B

    B:  Go to step  4

    A: Go to next step. 

  2. CLEAR DTC 
    1. Connect Techstream to the DLC3.
    2. Turn the power ON (IG).
    3. Turn the tester ON.
    4. Read DTCs (see DTC CHECK / CLEAR  ).
    5. Clear the DTCs (see DTC CHECK / CLEAR  ).
    6. Check that the MIL is not illuminated.

      OK: 

      MIL is not illuminated. 

    OK: REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

    NG: Go to next step. 

  3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) 
    1. Disconnect the E6 ECM connector.
    2. Turn the power switch ON (IG).
    3. Check that the MIL is not illuminated.

      OK: 

      MIL is not illuminated. 

    4. Reconnect the ECM connector.

    OK: REPLACE ECM 

    Fig 1: Identifying E6 ECM Connector Terminal
    G05188980Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK AND REPAIR HARNESS AND CONNECTOR (COMBINATION METER - ECM) 

  4. CHECK THAT MIL IS ILLUMINATED 
    1. Check that the MIL is illuminated when the power switch is turned ON (IG).

      Standard: 

      MIL is illuminated. 

    OK: SYSTEM OK 

    NG: Go to next step. 

  5. CHECK THAT ENGINE STARTS 
    1. Turn the power switch ON (IG).
    2. Start the engine.

      Result 

      RESULT CHART

      Result Proceed To
      Engine starts A
      Engine does not start* B
      HINT:
      *: Techstream cannot communicate with the ECM.

    B:  GO TO VC OUTPUT CIRCUIT 

    A: Go to next step. 

  6. INSPECT COMBINATION METER ECU (MIL CIRCUIT) 
    1. See the combination meter troubleshooting (see HOW TO PROCEED WITH TROUBLESHOOTING ).

    NG: REPAIR OR REPLACE BULB OR COMBINATION METER ASSEMBLY 

    OK: CHECK AND REPAIR HARNESS AND CONNECTOR (COMBINATION METER - ECM) 

Factory Service Tools

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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.

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