- Remove the engine vacuum hose from the vacuum brake booster.
- Install a vacuum gage to the engine vacuum hose.
- Start the engine. Verify the transmission is in Park or Neutral.
- Allow the engine to idle until the engine reaches normal operating
temperatures.
- Check to see if the engine vacuum meets or exceeds the minimum
specification.
Specification
The minimum engine vacuum is 17 in Hg (57.6 kPa)
- Turn the ignition OFF.
- If the engine vacuum reading meets or exceeds the minimum specification,
verify the check valve operates properly.
- If the engine vacuum reading is less than the minimum specification,
inspect the vacuum booster pipe and hoses for the following conditions.
| • | Loose connection to the engine |
| • | Collapse, deformation or contamination |
- Replace any defective vacuum booster pipe or hose. Refer to
Vacuum Brake Booster Hose Replacement
.
Important: If the engine does not produce proper vacuum, the vehicle will have
driveablilty conditions in addition to the brake assist condition.
- If none of these conditions exist on the pipe and hoses, then there
is an engine vacuum source problem. Check the engine vacuum system. Refer
to the following:
