Check Operation

While the engine is OFF, depress the brake pedal several times applying the same pedal force, to check for a change in pedal height.

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With the brake pedal depressed, start the engine.
As the engine starts, the brake pedal should move slowly toward the floor. If the pedal height does not change, the vacuum booster assembly is faulty.
NOTE: If a faulty part is detected after inspection, check precisely with measuring devices.