Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Wiring Diagram for Chart C-3 - Solenoid Valve Check
CHART C-3 - SOLENOID VALVE CHECK
Circuit Description:
Canister purge is controlled by a solenoid valve that allows manifold vacuum to purge the canister when de-energized. The ECM supplies a ground to
energize the solenoid (purge off). The solenoid is energized (no purge) by grounding the test terminal with the ignition "ON" and engine stopped, or with
the engine running if the following are met:
^
Engine run time less than specified.
^
Coolant temperature below a given value.
^
TPS below a given value.
If the above are not met, the solenoid valve is not energized.
Test Description:
1.
Checks to see if solenoid is energized and will not allow vacuum to pass.
2.
Checks to see if signal to energize solenoid (Light "ON") is present at the solenoid. Light "ON" is normal and would indicate no fault in ECM or
circuit to solenoid.
3.
Checks to see if solenoid passes vacuum when "test" terminal is ungrounded (solenoid de-energized). It should open and keep the pump from
building up a vacuum.
