2015 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE

Operation Check When Not Using Measuring Devices

WARNING: This page is about a different car, the 2015 Subaru Outback and 2015 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: When checking operation, be sure to apply the parking brake securely.

When an operation check is performed with no measuring devices, a faulty part cannot be identified correctly. But it is possible to identify the outline of the defect by performing the check according to the following procedures.

  • Air tightness check 
    1. Start the engine, and idle it for 1 to 2 minutes, then turn it OFF.
    2. Depress the brake pedal several times applying the normal pedal force.
      NOTE: The pedal stroke should be the longest at the 1st depression, and it should become shorter at each successive depression.
    3. If no change occurs in the pedal height when pressed, the vacuum booster assembly is faulty.
      Fig 1: Identifying Normal And NG Brake Pedal Application Force
      G10276718Courtesy of SUBARU OF AMERICA, INC.
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.