Emission Control System: Other Toyota Sequoia I

PURPOSE

The emission control systems are installed to reduce the amount of HC, CO and NOx exhausted from the engine, (3) and (4), to prevent the atmospheric release of blow-by gas-containing HC (1) and evaporated fuel containing HC being released from the fuel tank (2).

The function of each system is shown in the table: (Scheme 17)

Scheme 17

DRAWING

For a schematic drawing of the emission control system, see illustration. (Scheme 18)

Scheme 18

Scheme 19

Scheme 20

Scheme 21

1. Remove V-bank cover.
2. Inspect PCV valve: Remove the PCV valve. Install a clean hose to the PCV valve. Inspect the PCV valve operation. CAUTION: Do not suck air through the valve. Petroleum substances inside the valve are harmful. Blow air into the cylinder head side, and check that air passes through easily. (Scheme 19) Blow air into the intake manifold side, and check that air passes through with difficulty. (Scheme 20) If operation is not as specified, replace the PCV valve. Remove the clean hose from the PCV valve. Reinstall the PCV valve.
3. Visually inspect hoses, connections and gaskets for cracks, leaks or damage. (Scheme 21)
4. Reinstall V-bank cover.

COMPONENTS

For locations of EVAP components, see illustration. (Scheme 22)

Scheme 22

Scheme 23

Scheme 24

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Scheme 26

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

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Scheme 35

Scheme 36

Scheme 37

Scheme 38

1. Visually inspect lines and connections for loose connections, sharp bends or damage.
2. Visually inspect fuel tank for deformation, cracks or fuel leakage.
3. Visually inspect if fuel tank cap and/or gasket are deformed or damaged. (Scheme 23) If necessary, repair or replace the cap.
4. Inspect EVAP system line: Warm up the engine and stop the engine. Allow the engine to warm up to normal operating temperature. Install a vacuum gauge (EVAP control system test equipment vacuum gauge) to the EVAP service port on the purge line. (Scheme 24) TOYOTA Hand-Held Tester: Forced driving of the VSV for the EVAP. Connect a TOYOTA hand-held tester to the DLC3. Start the engine. Push the TOYOTA hand-held tester main switch ON. Use the ACTIVE TEST mode on the TOYOTA hand-held tester to operate the VSV for the EVAP. If you have no TOYOTA Hand-Held Tester: forced driving of the VSV for the EVAP. Disconnect the VSV connector for the EVAP. Connect the positive (+) and negative (-) leads from the battery to the VSV terminals for the EVAP. (Scheme 26) Start the engine. NOTE: 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. Check the vacuum at idle. Vacuum: maintain at 0.368 - 19.713 in.Hg (5 - 268 in.Aq) for over 5 seconds. (Scheme 27) TOYOTA Hand-Held Tester: Conclude forced driving of the VSV for the EVAP. Stop the engine. Disconnect the TOYOTA hand-held tester from the DLC3. If you have no TOYOTA Hand-Held Tester: Conclude forced driving of the VSV for the EVAP. Stop the engine. Disconnect the positive (+) and negative (-) leads from the battery from the VSV terminals for the EVAP. Connect the VSV connector for the EVAP. Disconnect the vacuum gauge from the EVAP service port on the purge line. Connect a pressure gauge to the EVAP service port on the purge line. Check the pressure. Close off the yellow marked position of the air drain hose with a hose clipper or similar instrument. (Scheme 28) NOTE: 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. Add the pressure (13.5 - 15.5 in.Aq) from the EVAP service port. (Scheme 29) Pressure: 2 minutes after the pressure is added, the gauge should be over 7.7 - 8.8 in.Aq. NOTE: 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. Check if the pressure decreases when the fuel tank cap is removed while adding pressure. (Scheme 30) Disconnect the pressure gauge from the EVAP service port on the purge line.
5. Check airtightness in fuel tank and filler pipe: 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/cm 2, 0.58 psi). (Scheme 31) Check that the internal pressure of the fuel tank can be held for 1 minute. Check the connected portions of each hose and pipe. Check the installed parts on the fuel tank. If there is no abnormality, replace the fuel tank and filler pipe. Reconnect the EVAP line hose to the charcoal canister.
6. Inspect fuel cutoff valve and fill check valve: Disconnect the purge line hose and EVAP line hose from the charcoal canister. (Scheme 31) Plug the cap to the air drain hose. (Scheme 32) NOTE: 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). Pressurize 4 kPa (41 gf/cm 2, 0.58 psi) to the purge port and check that there is ventilation through the EVAP line hose. 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. Reconnect the purge line hose and EVAP line hose to the charcoal canister.
7. Check air inlet line: Disconnect the air inlet line hose from the charcoal canister. (Scheme 33) Check that there is ventilation in the air inlet line. Reconnect the air inlet line hose to the charcoal canister.
8. Remove charcoal canister assembly.
9. Inspect charcoal canister Visually check the charcoal canister for cracks or damage. (Scheme 34) Inspect the charcoal canister operation. While holding the purge port closed, blow air (1.76 kPa, 18 gf/cm 2, 0.26 psi) into the EVAP port and check that air flows from the air drain port. (Scheme 35) 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. (Scheme 36) 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. (Scheme 37) 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. (Scheme 38) If operation is not as specified, replace the charcoal canister. Remove the cap from the vent port.
10. Inspect VSV for EVAP.
11. Inspect VSV for Canister Closed Valve (CCV).
12. Inspect VSV for pressure switching valve.
13. Inspect vapor pressure sensor.
14. Reinstall charcoal canister assembly.

For three-way catalytic converter component locations, see illustration. (Scheme 39)

Scheme 39