Chevrolet Workshop Service and Repair Manuals

1.

System operating properly.

Green & Yellow

1.

PCV valve or system partially plugged.

2.

Slight kink in tester hose.

3.

Slight engine blow-by.

4.

Plugs from kit or engine vacuum lines are not properly sealed.

5.

Tester knob improperly set.

Yellow

1.

PCV valve or system partially plugged.

2.

Tester hose kinked or blocked.

3.

Blow-by at maximum capacity of PCV valve.

4.

Plugs from kit or engine vacuum lines are not properly sealed.

5.

Tester knob improperly set.

Yellow & Red

1.

PCV valve or system partially or fully plugged.

2.

More engine blow-by than PCV valve can handle.

3.

Vent hose plugged or collapsed.

Red

1.

PCV valve or system fully plugged or stuck.

2.

Vent hose plugged or collapsed.

3.

Extreme blow-by.