Note:
| • | Engine temperature, accessory load, and elevation level will affect engine vacuum. |
| • | Vacuum readings will decrease by approximately 2.7 kPA (0.8 in Hg) for every 305 m (1000 ft) of elevation above sea level. |
- Disconnect the engine vacuum hose from the vacuum brake booster check valve.
- Install a vacuum gage to the engine vacuum hose.
- Start the engine and allow the engine to idle until normal operating temperatures are reached.
- With the vehicle in PARK, the engine idling, and the air conditioning (A/C) system OFF, check to see if the engine vacuum reading is within the specified normal engine vacuum range.
Specification
| • | Mechanical Vacuum Pump:
90 - 95 kPa (1305 - 1378 psi) |
| • | Electric Vacuum Pump:
40 - 70 kPa (580 - 1015 psi) |
- Turn the ignition OFF.
- If the engine vacuum reading is within the specified normal range, proceed to step 10.
- If the engine vacuum reading is NOT within the specified normal range, inspect the engine vacuum hose for the following conditions:
| • | Loose connection to the engine |
| • | Collapse, deformation or contamination |
- If any of these conditions were found with the engine vacuum hose, replace the hose, then repeat steps 2-4.
- If none of these conditions were found with the engine vacuum hose, then there is an engine vacuum source problem, check the engine vacuum system.
- Remove the vacuum brake booster check valve from the booster.
- Install the check valve to the engine vacuum hose.
- Install the vacuum gage to the check valve.
- Start the engine and allow the engine to idle in PARK with the A/C system OFF, until normal operating temperatures are reached.
- Turn the ignition OFF.
- Check to see if the engine vacuum reading is maintained within the specified normal engine vacuum range.
Specification
| • | Mechanical Vacuum Pump:
90 - 95 kPa (1305 - 1378 psi) |
| • | Electric Vacuum Pump:
40 - 70 kPa (580 - 1015 psi) |
- If the engine vacuum reading is maintained within the specified normal range, proceed to step 18.
- If the engine vacuum reading is NOT maintained within the specified normal range, replace the brake booster check valve, then repeat steps 11-15.
- Inspect the brake booster check valve grommet for the following conditions:
| • | Loose connection to the vacuum brake booster |
| • | Deformation or contamination |
- If any of these conditions were found with the check valve grommet, replace the grommet.
