Functional Test

WARNING: This page is about a different car, the 2002 Acura MDX, 2002 Acura 3.5RL, 2002 Acura 3.2TL, and 2002 Acura 3.2CL. However, it is still accessible from the selected car via links, so may be relevant.

With engine stopped, press brake pedal several times to deplete vacuum reservoir, then press pedal hard and hold it for 15 seconds. If pedal sinks, either master cylinder is bypassing internally, or brake system (master cylinder, lines, modulator, proportioning valve, or caliper) is leaking. Start engine with pedal pressed. If pedal sinks slightly, vacuum booster is operating normally. If pedal height does not vary, booster or check valve is faulty. With engine running, press brake pedal lightly. Apply just enough pressure to hold back automatic transmission creep. If brake pedal sinks more than 0.4" (10 mm) in 3 minutes, the master cylinder is faulty. A slight change in pedal height when the A/C compressor cycles on and off is normal. (The A/C compressor load changes the vacuum available to booster.)