Power Brake Unit Function Inspection
WARNING: This page is about a different car, the 2004 Mazda MX-5 Miata, 2003 Mazda MX-5 Miata, and 2002 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
Step 1
- With the engine stopped, depress the pedal a few times.
- With the pedal depressed, start the engine. If the pedal moves down slightly immediately after the engine starts, the unit is operating.
Step 2
- Start the engine.
- Stop the engine after it has run for 1 or 2 minutes.
- Depress the pedal with the usual force.
- If the first pedal stroke is long and becomes shorter with subsequent strokes, the unit is operating.
- If a problem is found, inspect for damage or improper connection of the check valve or vacuum hose. Repair if necessary and inspect it once again.
Step 3
- Start the engine.
- Depress the pedal with the usual force.
- Stop the engine with the pedal held depressed.
- Hold the pedal down for about 30 seconds.
- If the pedal height does not change, the unit is operating.
- If there is a problem, inspect for damage or improper connection of the check valve or vacuum hose. Repair if necessary and inspect it once again.
- If the nature of the problem is still not clear after following the above steps, follow the more detailed inspection, described in Inspection Using Gauges. See POWER BRAKE UNIT FUNCTION INSPECTION (INSPECTION USING GAUGES) .