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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 99 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0442: Evaporative Emission Control System Leak Detected (Small Leak) Or DTC P0456: Evaporative Emission Control System Leak Detected (Very Small Leak) >> Diagnosis & Repair (OBD-II Scan Tool)

Diagnosis & Repair (OBD-II Scan Tool)

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check that fuel tank cap is Lexus genuine parts. Replace as necessary. If okay, go to next step.
  2. Check that fuel tank cap is correctly installed. Correctly install fuel tank cap as necessary. If okay, go to next step.
  3. Check fuel tank cap for damage. Replace as necessary. If okay, go to next step.
  4. Check filler neck for damage. Replace filler pipe as necessary. If okay, go to next step.
  5. Check whether hose close to fuel tank has been modified, and check whether there are signs of any accident near fuel tank or charcoal canister. See Figure. Check for cracks, deformation and loose connection of fuel tank, charcoal canister, fuel tank filler pipe, hoses and tubes around fuel tank and charcoal canister. If okay, go to next step.
  6. Check vacuum hoses between vapor pressure sensor and fuel tank, charcoal canister and VSV for pressure switching valve, and VSV for pressure switching valve and charcoal canister. Repair as necessary. If okay, go to next step.
  7. Check hose and tube between fuel tank and charcoal canister. Check for proper connection of the fuel tank and fuel evaporation pipe, fuel evaporation pipe and fuel tube under the floor, fuel tube under the floor and charcoal canister. Repair as necessary. If okay, go to next step.
  8. Check VSV connector for EVAP, VSV connector for CCV, VSV connector for pressure switching valve and vapor pressure sensor connector for looseness and disconnection. Repair as necessary. If okay, go to next step.
  9. Check vacuum hoses. See Figure. Repair as necessary. If okay, go to next step.
  10. Remove glove compartment door. Turn the ignition switch ON. Measure the voltage between terminals VC and E2 of ECM connector. See Figure. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, check and replace ECM.
  11. Measure the voltage between terminals PTNK and E2 of the ECM connectors. Disconnect the vacuum hose from the vapor pressure sensor. Using the MITYVAC (hand-held vacuum pump), apply a vacuum of 1.18 in. Hg (30 mm Hg) to the vapor pressure sensor. See Figure. Vacuum applied to vapor pressure sensor must be less than 19.7 in. Hg (500 mm Hg). If voltage is 2.9-3.7 volts when vacuum hose is disconnected, then drops to less than 0.5 volts, go to step  13. If not, go to next step.
  12. Check for open and short in harness and connector between vapor pressure sensor and ECM. Repair as necessary. If okay, replace vapor pressure sensor.
  13. Connect jumper wire between terminal EVP1 of the ECM connector and body ground (ON), then disconnect jumper wire (OFF). When VSV is on, air from port "E" flows out through port "F". When VSV Is OFF, air does not flow from port "E" to port "F". See Figure. If okay, go to step  16. If not okay, go to next step.
  14. Check operation of VSV for EVAP. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - LX470 article. If okay, go to next step. If not okay, replace VSV and clean vacuum hoses between throttle body and VSV for EVAP, and VSV for EVAP and charcoal canister, and then check charcoal canister.
  15. Check for open and short in harness and connector between EFI or ECD relay and VSV for EVAP, and VSV for EVAP and ECM. Repair or replace harness or connector as necessary. If okay, check and replace ECM.
  16. Connect jumper wire between terminal CCV of the ECM connector and body ground (ON), then disconnect jumper wire (OFF). When VSV is ON, air does not flow from port "E" to port "F". When VSV is OFF, air from port "E" flows out through port "F". See Figure. If okay, go to step  19. If not okay, go to next step.
  17. Check operation of VSV for CCV. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEMS & COMPONENT TESTING - LX470. If okay, go to next step. If not okay, replace VSV and charcoal canister, and then clean vacuum hose between charcoal canister and VSV for CCV.
  18. Check for open and short in harness and connector between EFI or ECD relay and VSV for CCV, and VSV for CCV and ECM. Repair as necessary. If okay, check and replace ECM.
  19. Connect jumper wire between terminal TBP of the ECM and body ground (ON), then disconnect jumper wire (OFF). When VSV is ON, air from port "E" flows out through port "F". When VSV is OFF, air does not flow from port "E" to port "F". See Figure. If okay, check and replace charcoal canister. If not okay, go to next step.
  20. Check operation of VSV for pressure switching valve. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - LX470 article. If okay, go to next step. If not okay, replace VSV and charcoal canister, and then clean vacuum hoses between charcoal canister and VSV for pressure switching valve, and VSV for pressure switching valve and fuel tank.
  21. Check for open and short in harness and connector between EFI or ECD relay and VSV for pressure switching valve, and VSV for pressure switching valve and ECM. Repair as necessary. If okay, check and replace ECM.
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