Start and warm engine to normal operating temperature. With engine idling, disconnect top hose from No. 1 purge control valve on charcoal canister. Install a vacuum gauge to hose. Increase engine speed to 2500 RPM. Ensure vacuum exceeds 5.9 in. Hg. If not, check water thermo valve. Remove vacuum gauge. Reconnect vacuum hose.
Disconnect vacuum hose from port "B" of No. 3 purge control valve. Connect vacuum gauge and hose to valve port. See Figure . Accelerate engine to a speed greater than 1500 RPM. Note that vacuum is present at port. If vacuum is not present, check 3-way solenoid valve, No. 3 purge control valve, and terminal "2P" at ECU.
Remove vacuum gauge and hose. Reconnect vacuum hose to purge control valve. Disconnect fuel tank hose from charcoal canister. Connect vacuum pump/gauge to hose. Try to apply vacuum to hose. Vacuum should not be held. If vacuum is held, check 3-way valve or fuel tank hose for blockage.

Fig 1: Fuel Evaporation System (626)

Courtesy of MAZDA MOTORS CORP.

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

Fuel Injected Models: 626