Basic Test
WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
- With engine off, depress and release the brake pedal several times to purge all vacuum from the power brake booster.
- Depress and hold the pedal with light effort (15 to 25 lbs. pressure), then start the engine.
The pedal should fall slightly, then hold. Less effort should be needed to apply the pedal at this time. If the pedal fell as indicated, perform the VACUUM LEAK TEST listed after the BASIC TEST. If the pedal did not fall, continue on with this BASIC TEST.
- Disconnect the vacuum hose on the side of the vacuum check valve that leads to the speed control, then connect a vacuum gauge to the open vacuum port on the valve.
- Start the engine.
- When the engine is at warm operating temperature, allow it to idle and check the vacuum at the gauge.
If the vacuum supply is 12 inches Hg (40.5 kPa) or more, the power brake booster is defective and must be replaced. If the vacuum supply is below 12 inches, continue on with this BASIC TEST.
- Shut off the engine.
- Connect the vacuum gauge to the vacuum reference port on the engine intake manifold.
- Start the engine and observe the vacuum gauge.
If the vacuum is still low, check the engine tune and repair as necessary. If the vacuum is above 12 inches, the hose or check to the booster has a restriction or leak.
Once an adequate vacuum supply is obtained, repeat the BASIC TEST.