Caution: Do not breathe the air through the EVAP component tubes or hoses. The fuel vapors inside the EVAP components may cause personal injury.

Important: Before diagnosing any EVAP control system malfunction, perform a careful visual inspection of the EVAP control system components and of the connecting hoses .

1. Allow the engine to cool to room temperature.
2. Start the engine.



3. Disconnect the purge hose (1) from the EVAP canister purge valve (2).
4. Place a finger against the end of the disconnected hose in order to check for vacuum. Vacuum should not be felt if the engine temperature is below a normal operating temperature.
5. Connect the purge hose to the EVAP canister,and warm the engine to a normal operating temperature.
6. Disconnect the purge hose (1) from the EVAP canister purge valve (2).

Important: The EVAP control system does not purge the EVAP canister unless the engine is sufficiently warmed up, and the heated oxygen sensor (HO2S) is activated. When the purge hose is disconnected, as in Step 6, some air may be drawn into the purge line. As a result, the powertrain control module (PCM) may detect a change in the purge gas concentration and may stop the purge. This is a normal action and may be the cause of a failure to detect vacuum in step 7. If vacuum is not present in Step 7, continued testing of the EVAP system may be necessary in order to avoid the replacement of good parts.

7. Place a finger over the disconnected hose in order to check for a vacuum. Vacuum should be felt with the engine running at normal operating temperature.

Failure of the EVAP control system to pass any of these checks indicates a possible malfunction that will require further inspection.

1. Disconnect the four hoses from the EVAP canister.
2. Blow air into the tank port A (3) of the EVAP canister. The air should flow freely through the EVAP canister and out of the purge port (2), out of the tank port B (1), and out of the air port (4).
3. Replace the EVAP canister if the EVAP canister fails the above check. Refer to Evaporative Emission Canister Replacement .
4. Connect the four hoses to the EVAP canister.

1. Disconnect the electrical connector from the EVAP canister purge valve.
2. Measure the resistance between the electrical terminals of the EVAP canister purge valve (2) with the DMM (1). The resistance should be between 30-34 ohms at 20°C (68°F).
3. Replace the EVAP canister purge valve if the resistance is not between 30-34 ohms at 20°C (68°F). Proceed to step 4 if the resistance is within the specification. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .



4. Disconnect the vacuum hose (1) of the EVAP canister purge valve from the intake manifold pipe.
5. Disconnect the vacuum hose (2) from the EVAP canister purge pipe.
6. Blow air into the vacuum hose (2) that was disconnected from the EVAP canister purge pipe. Air should not pass through the EVAP canister purge valve (3) and exit from the intake manifold hose (1).



7. Connect 12 volts DC to the electrical terminals of the EVAP canister purge valve .
8. Blow air into the vacuum hose (2) that was disconnected from the EVAP canister purge pipe. Air should pass through the EVAP canister purge valve and exit from the intake manifold hose (1).
9. Replace the EVAP canister purge valve if the EVAP canister purge valve failed this inspection. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .
10. Connect the vacuum hoses to the EVAP canister purge valve.
11. Connect the electrical connector to the EVAP canister purge valve.

1. Disconnect the electrical connector from the EVAP-canister vent solenoid.
2. Use the DMM in order to measure the resistance between the electrical terminals of the EVAP-canister vent solenoid (2). The resistance should be 25-30 ohms at 20°C (68°F).
3. Replace the EVAP-canister vent solenoid if the resistance is not 25-30 ohms at 20°C (68°F). Proceed to step 4 if the resistance is within the specification. Refer to Evaporative Emission Canister Vent Solenoid Replacement .



4. Disconnect the EVAP-canister vent solenoid hose from the EVAP canister.
5. Blow air into the EVAP-canister vent hose that is disconnected from the EVAP canister. Air should pass through the EVAP-canister vent solenoid.



6. Connect 12 volts DC to the electrical terminals of the EVAP canister vent solenoid .
7. Blow air into the EVAP-canister vent vacuum hose that was disconnected from the EVAP canister. Air should not pass through the EVAP-canister vent solenoid and exit from the other end.
8. Replace the EVAP-canister vent solenoid, if the EVAP-canister vent solenoid failed this inspection. Refer to Evaporative Emission Canister Vent Solenoid Replacement .
9. Reconnect the hose to the EVAP-canister vent solenoid.
10. Reconnect the electrical connector to the EVAP-canister vent solenoid.

1. Disconnect the electrical terminals from the EVAP pressure control valve.
2. Measure the resistance between the electrical terminals of the EVAP pressure control valve with the DMM. The resistance should be 33-39 ohms at 20°C (68°F).
3. Replace the EVAP pressure control valve if the resistance is not 30-34 ohms at 20°C (68°F). Proceed to step 3 if the resistance is within the specification. Refer to Evaporative Emission Tank Pressure Control Solenoid Valve Replace .



4. Disconnect the vacuum hoses from the EVAP tank pressure valve.
5. Blow air into the port of the EVAP pressure control valve (3). Air should not pass through the EVAP pressure control valve (2) and exit from the port (1).



6. Connect 12 volts DC to the electrical terminals of the EVAP pressure control valve.
7. Blow air into the port of the EVAP pressure control valve (3). Air should pass through the EVAP pressure control valve (2) and exit from port (1).
8. Replace the EVAP pressure control valve if the valve failed this inspection. Refer to Evaporative Emission Tank Pressure Control Solenoid Valve Replace .
9. Reconnect the vacuum hoses to the EVAP pressure control valve.
10. Reconnect the electrical connector to the EVAP pressure control valve.

Tools Required

J 23738-A Hand Vacuum Pump

1. Connect a hose to the fuel tank side of the pressure control valve on the fuel tank.
2. Blow hard into the hose. Some air should pass through the valve from the fuel tank side to the canister side when blown hard.



3. Remove the hose from the fuel tank side, and connect the hose to the canister side of the pressure control valve.
4. Blow easily into the hose. Even lightly blown air should pass smoothly through the valve from the canister side to the fuel tank side.
5. Replace the pressure control valve if the valve fails any of the above checks. Refer to Fuel Tank Pressure Control Valve Replacement .