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Home >> Toyota >> 2003 >> Matrix Base, FWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 13 (Engine Control System Self-Diagnostics - V6) >> Diagnostic Tests >> DTC P0441: Incorrect EVAP Purge Flow Or DTC P0446: EVAP Vent Control Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
  3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
  4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
  5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem does not exist, go to next step. If problem exists, replace fuel tank filler pipe as necessary.
  6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
  7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
  8. Check all EVAP system electrical component connections. If problem does not exist, go to next step. If problem exists, repair as necessary.
  9. Check vacuum hoses between charcoal canister and fuel tank, and between fuel tank filler pipe and fuel tank. If problem does not exist, go to next step. If problem exists, repair as necessary.
  10. Access ECM behind glove box. See Figure. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. 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.
  11. Turn ignition off. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 17 (Blue/Black wire) at ECM harness connector E5 and terminal No. 18 (White wire) at ECM harness connector E8. See Figure. Disconnect vacuum hose from vapor pressure sensor. See Figure. Vapor pressure sensor is mounted above fuel tank, near fuel level sensor. Connect a vacuum pump to vapor pressure sensor. Turn ignition on. Voltage should be 2.9-3.7 volts without vacuum applied, and .5 volt or less with 1.18 in. Hg applied. If voltage is not as specified, go to next step. If voltage is as specified, go to step  13.
  12. Check for an open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  13. Disconnect EVAP VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. See Figure. Connect a jumper wire by backprobing between ground and terminal No. 7 (Black/Red wire) at ECM harness connector E8. See Figure. With jumper wire connected, air applied to EVAP VSV port "E" should flow from port "F". See Fig 1. Remove jumper wire. With jumper wire removed, air applied to EVAP VSV port "E" should not flow from port "F". If EVAP VSV does not function as specified, go to next step. If EVAP VSV functions as specified, go to step  16.
  14. Connect all disconnected components. Check EVAP VSV operation. See FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If EVAP VSV is okay, go to next step. If EVAP VSV is not okay, replace EVAP VSV and charcoal canister. Also, clean vacuum hose between throttle body and EVAP VSV, and between EVAP VSV and charcoal canister.
  15. Check for an open or short in wiring between EFI relay and EVAP VSV, and between EVAP VSV and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  16. Disconnect canister closed valve VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. See Figure. Connect a jumper wire by backprobing between ground and terminal No. 10 (Pink wire) at ECM harness connector E5. See Figure. With jumper wire connected, air applied to canister closed valve VSV port "E" should not flow from port "F". See Fig 2. Remove jumper wire. With jumper wire removed, air applied to canister closed valve VSV port "E" should flow from port "F". If canister closed valve VSV does not function as specified, go to next step. If canister closed valve VSV functions as specified, go to step  19.
  17. Connect all disconnected components. Check canister closed valve VSV. See FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If canister closed valve VSV is okay, go to next step. If canister closed valve VSV is defective, replace canister closed valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and canister closed valve VSV.
  18. Check for an open or short in wiring between EFI relay and canister closed valve VSV, and between canister closed valve VSV and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  19. Disconnect pressure switching valve VSV vacuum hoses. Pressure switching valve VSV is located next to charcoal canister. Turn ignition on. Access ECM behind glove box. See Figure. Connect a jumper wire by backprobing between ground and terminal No. 3 (Green/Yellow wire) at ECM harness connector E6. See Figure. With jumper wire connected, air applied to pressure switching valve VSV port "E" should flow from port "F". See Fig 3. Remove jumper wire. With jumper wire removed, air applied to pressure switching valve VSV port "E" should not flow from port "F". If pressure switching valve VSV does not function as specified, go to next step. If pressure switching valve VSV functions as specified, go to step  22.
  20. Connect all disconnected components. Check pressure switching valve VSV. See FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If pressure switching valve VSV is okay, go to next step. If pressure switching valve VSV is defective, replace pressure switching valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and pressure switching valve VSV, and between pressure switching valve VSV and fuel tank.
    21. NOTE: Circuit between pressure switching valve VSV and ECM changes color. Circuit is a Green/Yellow wire at ECM and is a Blue/Red wire at pressure switching valve VSV.
  21. Check for an open or short in wiring between EFI relay and pressure switching valve VSV, and between pressure switching valve VSV and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  22. Charcoal canister or fuel tank overfill check valve maybe defective. Check fuel evaporative system. See FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. Repair as necessary.
Fig 1: Identifying EVAP Vacuum Switching Valve Vacuum Ports
G96D09634Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Identifying Canister Closed Valve Vacuum Switching Valve Vacuum Ports
G99G54151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Identifying Pressure Switching Valve Vacuum Switching Valve Vacuum Ports
G99A52753Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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