Evaporative Emission (EVAP) Control System: Inspection

Visually check for loose connections, sharp bends or damage.

Visually check for deformation, cracks or fuel leakage.

Visually check if the cap and/or gasket are deformed or damaged.

If necessary, repair or replace the cap.

Fig 1: Identifying Gasket

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1. Warm up the engine and stop the engine.

   Allow the engine to warm up to normal operating temperature.

2. Install a vacuum gauge (EVAP control system test equipment vacuum gauge) to the EVAP service port on the purge line.
   Fig 2: Installing Vacuum Gauge To EVAP System Line

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3. LEXUS Hand-Held tester:

   Forced driving of the VSV for the EVAP.

   1. Connect a LEXUS hand-held tester to the DLC3.
   2. Start the engine.
   3. Push the LEXUS hand-held tester main switch ON.
   4. Use the ACTIVE TEST mode on the LEXUS handheld tester to operate the VSV for the EVAP.
   Fig 3: Connecting LEXUS Hand-Held Tester To DLC3

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4. If you have no LEXUS Hand-Held Tester:

   Forced driving of the VSV for the EVAP.

   1. Disconnect the VSV connector for the EVAP.
   2. Connect the positive (+) and negative (-) leads from the battery to the VSV terminals for the EVAP.
   3. Start the engine.
   Fig 4: Operating VSV Without LEXUS Hand-Held Tester

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5. Check the vacuum at idle.

   Vacuum: 

   Maintain at 0.368 - 19.713 in.Hg (5 - 268 in.Aq) for over 5 seconds 

   HINT:

   If the vacuum does not change, you can conclude that the hose connecting the VSV to the service port has come loose or is blocked, or the VSV is malfunctioning.

   Fig 5: Checking Vacuum At Vacuum Gauge

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6. LEXUS Hand-Held Tester:

   Conclude forced driving of the VSV for the EVAP.

   1. Stop the engine.
   2. Disconnect the LEXUS hand-held tester from the DLC3.
7. If you have no LEXUS Hand-Held Tester:

   Conclude forced driving of the VSV for the EVAP.

   1. Stop the engine.
   2. Disconnect the positive (+) and negative (-) leads from the battery from the VSV terminals for the EVAP.
   3. Connect the VSV connector for the EVAP.
8. Disconnect the vacuum gauge from the EVAP service port on the purge line.
9. Connect a pressure gauge to the EVAP service port on the purge line.
10. Check the pressure.
    1. Close off the air drain hose at the marked position of the canister with a hose clipper or similar instrument.
       Fig 6: Closing Air Drain Hose

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    2. Add the pressure (13.5 - 15.5 in.Aq) from the EVAP service port.

       Pressure: 

       minutes after the pressure is added, the gauge should be over 7.7 - 8.8 in.Aq. 

       HINT:

       If you can't add pressure, you can conclude that the hose connecting the VSV ~ canister ~ fuel tank has slipped off or the VSV is open.

       Fig 7: Adding Pressure From EVAP Service Port

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    3. Check if the pressure decreases when the fuel tank cap is removed while adding pressure.

    HINT:

    If the pressure does not decrease when the filler cap is removed, then you can conclude that the hose connecting the service port to the fuel tank is blocked, etc.

11. Disconnect the pressure gauge from the EVAP service port on the purge line.

Fig 8: Removing Fuel Tank Cap To Release Pressure

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1. Disconnect the EVAP line hose from the charcoal canister side and then pressurize and make the internal pressure in the fuel tank 4 kPa (41 gf/cm² , 0.58 psi).
2. Check that the internal pressure of the fuel tank can be hold for 1 minute.
3. Check the connected portions of each hose and pipe.
4. Check the installed parts on the fuel tank.

   If there is no abnormality, replace the fuel tank and filler pipe.

5. Reconnect the EVAP line hose to the charcoal canister.

Fig 9: Disconnecting EVAP Line Hose From Charcoal Canister

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1. Disconnect the purge line hose and EVAP line hose from the charcoal canister.
2. Plug the cap to the air drain hose.
3. Pressurize 4 kPa (41 gf/cm² , 0.58 psi) to the purge port and check that there is ventilation through the EVAP line hose.

   HINT:

   In the condition that the fuel is full, as the float value of the fill check valve is closed and has no ventilation, it is necessary to check the fuel amount (volume).

4. Check if there is any struck in the vent line hose and EVAP line hose.

   If there is no stuck in hoses, replace the fuel cutoff valve and fill check valve.

5. Reconnect the purge line hose and EVAP line hose to the charcoal canister.

Fig 10: Disconnecting Purge Line Hose And EVAP Line Hose From Charcoal Canister

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1. Disconnect the air inlet line hose from the charcoal canister.
2. Check that there is ventilation in the air inlet line.
3. Reconnect the air inlet line hose to the charcoal canister.

Fig 11: Disconnecting Air Inlet Line Hose From Charcoal Canister

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1. Visually check the charcoal canister for cracks or damage.
   Fig 12: Checking Charcoal Canister

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2. Inspect the charcoal canister operation.
   1. While holding the purge port closed, blow air (1.76 kPa, 18 gf/cm² , 0.26 psi) into the EVAP port and check that air flows from the air drain port.
      Fig 13: Checking Air Flows From Air Drain Port

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   2. While holding the purge port and the air drain port closed, blow air (1.76 kPa, 18 gf/cm> ² , 0.26 psi) into the EVAP port and check that air does not flow from the air inlet port.
      Fig 14: Checking Flow From Air Inlet Port

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   3. Apply vacuum (3.43 kPa, 25.7 mmHg, 1.01 in.Hg) to the purge port, check that the vacuum does not decrease when the air inlet port is closed, and check that the vacuum decreases when the air inlet port is released.
      Fig 15: Applying Vacuum To Purge Port

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   4. While holding the air inlet port closed, apply vacuum (3.43 kPa, 25.7 mmHg, 1.01 in Hg) to the EVAP port and check that air flows into the purge port.

      If operation is not as specified, replace the charcoal canister.

   5. Remove the cap from the vent port.
   Fig 16: Checking Air Flows Into Purge Port

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