DTC Confirmation Test (Overall Function Check)

Malfunction is detected when EVAP system is not functioning properly or there is a leak in hose between EVAP Control System Pressure Sensor (EVAP-CSPS) and intake manifold. Possible causes are:

• EVAP Canister Purge Volume Control Valve (EVAP-CPVCV) stuck closed.
• Faulty EVAP-CSPS or circuit.
• Blockage or leak in hoses.
• EVAP canister cracked.
• Fault in EVAP-CPVCV circuit.
• Defective closed Throttle Position (TP) switch.
• Plugged purge port.
• Defective EVAP Canister Vent Control Valve (EVAP-CVCV).

To check overall function of purge flow monitoring system, start engine and warm to normal operating temperature. Turn ignition off and wait at least 5 seconds. Start engine and wait at least 70 seconds. With engine idling, measure and record voltage between ECM terminal No. 67 (EVAP-CSPS signal) and ground by backprobing. See Figure. Raise drive wheels and support vehicle. While monitoring voltage, maintain the following conditions for at least one minute:

• A/C on.
• Steering wheel turned fully.
• Headlights on.
• Engine speed at 3000 RPM.
• Rear window defogger on.
• Transmission in any forward gear.

Ensure voltage remains .1 volt less than voltage measured at idle for at least one second.