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Home >> Toyota >> 1998 >> RAV4 Base, 4D Utility, AWD, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Self-Diagnostic Tests >> DTC P0441: Incorrect EVAP Purge Flow DTC P0446: Vent Control Malfunction >> Diagnosis & Repair (Using Toyota Scan Tool)
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Diagnosis & Repair (Using Toyota Scan Tool)

  1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. EVAP VSV is mounted on air filter housing. Vapor pressure sensor is located on firewall, near brake master cylinder. Vapor pressure sensor VSV is located on top of charcoal canister on left side of engine compartment. Repair as necessary. If connectors are okay, go to next step. For component locations, see appropriate illustration in THEORY/OPERATION article.
  2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. Replace vacuum hoses as necessary. If vacuum hoses are okay, go to next step. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article.
  3. Access ECM behind bottom center of instrument panel, in front of console. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E5 connector. See Figure. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
  4. Backprobing ECM connector, measure voltage between terminals No. 7 (Blue/Yellow wire) and No. 9 (Brown wire) at ECM E5 connector. Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to sensor. If voltage is 3.0-3.6 volts without vacuum applied and 1.3-2.1 volts with .59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
  5. Check for open or short circuit in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace vapor pressure sensor.
  6. Connect scan tool to DLC No. 3. Turn ignition on. Using scan tool, select ACTIVE TEST mode. Disconnect EVAP VSV vacuum hose from charcoal canister. See Fig 1-5. Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by scan tool, vacuum should be present. When EVAP VSV is not activated, no vacuum should be present. If vacuum is as specified, go to step 10). If vacuum is not as specified, go to next step.
    Fig 1: Testing EVAP Vacuum Switching Valve (VSV) VSV On
    G98I10213Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 2: Testing EVAP Vacuum Switching Valve (VSV) VSV Off
    G98H10212Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. Check vacuum hose between intake manifold and EVAP VSV, and between EVAP VSV and charcoal canister. Check for correct routing, damage, blockage and for proper connections. Replace vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
  8. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
  9. Check for open or short circuit in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
  10. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted on top of charcoal canister in left side of engine compartment. Apply air pressure to VSV port "E". See Fig 3. Air from port "E" should flow from port "G" only. Using scan tool, select ACTIVE TEST mode. With VSV on, air from port "E" should flow from port "F". If VSV operates as specified, go to step 13). If VSV does not operate as specified, go to next step.
  11. Check vapor pressure sensor VSV operation. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
  12. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
  13. Turn ignition on. Disconnect vapor pressure sensor VSV connector. Start and run engine. Using scan tool, select ACTIVE TEST mode. Measure voltage between terminals No. 7 (Blue/Yellow wire) and No. 9 (Brown wire) at ECM E5 connector. With EVAP VSV activated, voltage should be 2 volts or less. If voltage is as specified, go to step 15). If voltage is not as specified, go to next step.
  14. Check vacuum hose between charcoal canister and vapor pressure sensor VSV. Also, check vacuum hose between vapor pressure sensor and vapor pressure sensor VSV. Check for correct routing, damage, blockage and for proper connections. Replace vacuum hose as necessary. If vacuum hose is okay, go to next step.
  15. Remove fuel tank cap. Disconnect vapor pressure sensor VSV connector. Using scan tool, select ACTIVE TEST mode. Start engine. Using scan tool, switch EVAP VSV on. Backprobing ECM connector, measure voltage between terminals No. 7 (Blue/Yellow wire) and No. 9 (Brown wire) at ECM E5 connector 5 seconds after switching EVAP VSV from on to off. If voltage is 2.5 volts or less, replace charcoal canister. If voltage is more than 2.5 volts, go to next step.
  16. Check charcoal canister. See appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary. If charcoal canister is okay, replace ECM.
Fig 3: Identifying Vapor Pressure Sensor Vacuum Switching Valve (VSV)
G96C10183Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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