Warm engine to normal operating temperature. Stop engine and disconnect outlet hose from bottom of air control valve. Start engine and run at idle speed.
Disconnect vacuum hose from vacuum delay valve at air control valve. Air should be discharged from outlet port of air control valve. Reconnect vacuum hose. Air should not be discharged from outlet port.
Disconnect and plug vacuum hose from water thermo valve at air control valve. Using a "T" fitting and additional tubing, install "T" between intake manifold and evaporative shutter valve.
Connect additional tubing to "T" and water thermo valve port of control valve so intake manifold vacuum is applied directly to control valve. Air should be discharged from air control valve outlet port.
Disconnect and plug tubing, that was just connected to water thermo valve port of control valve. Air should not be discharged from air control valve outlet port. If air control valve does not respond as described, replace air control valve.

Fig 1: Testing Air Control Valve Disconnect outlet hose from bottom of control valve.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Air Control Valve