2007 Toyota Prius BaseFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

HINT:

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
  • Malfunctioning areas can be found by performing the ACTIVE TEST / A/F CONTROL operation. The A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble area are malfunctioning or not.
    1. Perform the ACTIVE TEST A/F CONTROL operation.
  • The A/F CONTROL operation lowers the injection volume 12.5% or increases the injection volume 25%.
    1. Connect the intelligent tester to the DLC3.
    2. Turn the power switch ON (IG).
    3. Put the engine in inspection mode (See SFI SYSTEMΒ  ).
    4. Warm up the engine by running the engine at 2,500 rpm, depressing the accelerator pedal more than 60% for approximately 90 seconds.
    5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
    6. Perform the A/F CONTROL operation with the engine in an idle condition (press the right or left button).

Result:Β 

A/F sensor reacts in accordance with increase and decrease of injection volume:Β 

+25% β†’ rich output: Less than 3.0 VΒ 

-12.5% β†’ lean output: More than 3.35 VΒ 

Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:Β 

+25% β†’ rich output: More than 0.55 VΒ 

-12.5% β†’ lean output: Less than 0.4 VΒ 

NOTE: The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has about 20 seconds of delay at maximum.
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:

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