LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2000 >> LX 470 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Emission Systems & Sub-Systems >> Fuel Evaporation System >> Fuel EVAP System Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fuel EVAP System Test

NOTE: Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister and fuel EVAP system.
  1. Inspect all lines and connections for sharp bends or damage. Inspect fuel tank for damage, cracks or fuel leakage. Inspect fuel tank cap for cracks or deformed gasket. Replace components if defective or damaged.
  2. Start engine and warm engine to normal operating temperature. Shut engine off. Connect vacuum gauge from EVAP system test kit to EVAP service port. EVAP service port is located in purge vacuum hose for EVAP system near charcoal canister in engine compartment. See Figure.
  3. EVAP Vacuum Switching Valve (VSV) must be operated. If scan tool is available, go to next step. If scan tool is not available, go to step  5.
  4. Connect scan tool to data link connector No. 3. See Figure. Start engine. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate EVAP VSV. Go to step  6.
  5. Disconnect EVAP VSV electrical connector. EVAP VSV is located on driver's side center of intake manifold below intake manifold cover on top of engine and contains Black 2-Pin electrical connector with Blue/Black and Black/Yellow wires. See Figure. Using jumper wires, connect battery voltage and ground to electrical terminals on EVAP VSV to operate EVAP VSV. Start engine. Go to next step.
  6. Check vacuum reading on vacuum gauge with engine idling. Vacuum should be .368-19.713 in Hg. for more than 5 seconds. If vacuum is within specification, go to next step. If vacuum reading is not within specification, check for loose or restricted vacuum hose to EVAP service port, or for malfunctioning EVAP VSV. To check EVAP VSV operation, see EVAP VACUUM SWITCHING VALVE .
  7. Shut engine off. If using scan tool to operate EVAP VSV, stop operation of EVAP VSV. Remove scan tool. Go to next step. If connecting battery voltage to EVAP VSV to operate EVAP VSV, disconnect jumper wires and reconnect electrical connector on EVAP VSV. Go to next step.
  8. Disconnect vacuum gauge from EVAP service port. Connect pressure gauge to EVAP service port. Install hose crimper on air drain hose near charcoal canister. See Fig 1. Charcoal canister is located in driver's side of engine compartment. See Figure.
    Fig 1: Installing Hose Crimper On Air Drain Hose
    G99B08756Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  9. Apply 13.5-15.5 in. H2 O of pressure to EVAP service port. After 2 minutes of applying the pressure, the pressure should be 7.7-8.8 in. H2 O. If pressure is within specification, remove hose crimper and go to next step. If pressure cannot be maintained, remove hose crimper and check for disconnected vacuum hose between EVAP VSV, charcoal canister and fuel tank. If vacuum hose is properly installed on EVAP VSV, charcoal canister and fuel tank, check for stuck open EVAP VSV. To check EVAP VSV operation, see EVAP VACUUM SWITCHING VALVE .
  10. With pressure still applied at EVAP service port, remove fuel tank cap and note pressure reading. Pressure should decrease when fuel tank cap is removed. If pressure decreases when fuel tank cap is removed, remove pressure gauge and go to next step. If pressure does not decrease when fuel tank cap is removed, remove pressure gauge and check for restricted vacuum hose between EVAP service port, charcoal canister and fuel tank. Repair or replace vacuum hose as necessary.
  11. Remove charcoal canister. Inspect charcoal canister for cracks or damage at all hose fittings. If charcoal canister is okay, go to next step. If charcoal canister is defective, replace charcoal canister.
  12. Apply .26 psi (.018 kg/cm2 ) air pressure to port "A" while holding port "B" closed. See Fig 2. Ensure air flows freely from port "D".
  13. Apply .26 psi (.018 kg/cm2 ) air pressure to port "A" while holding ports "B" and "D" closed. See Fig 2. Ensure no air flows from port "C".
  14. Using vacuum pump, apply 1.01 in. Hg of vacuum to port "B". Ensure vacuum does not decrease when port "C" is closed, and that vacuum decreases when port "C" is opened.
  15. While holding port "C" closed, use vacuum pump to apply .39 in. Hg of vacuum to port "A". Ensure air flows into port "B". Replace charcoal canister if defective.
  16. Reinstall charcoal canister. If fuel EVAP system operates properly, it may be necessary to check operation of EVAP Vacuum Switching Valve (VSV), vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV). See EVAP VACUUM SWITCHING VALVE , VAPOR PRESSURE SENSOR  and VAPOR PRESSURE SENSOR VACUUM SWITCHING VALVE  .
    Fig 2: Identifying Charcoal Canister Ports
    G98I12490Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
scientia non olet · About LEMON Manuals