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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 100 (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 SC 430. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check that fuel tank cap is a Lexus genuine part. 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. 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. See Figure. Repair as necessary. 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 8, 9, 10 and 11. See Figure. Repair as necessary. If okay, go to next step.
  10. Turn the ignition switch ON. Measure the voltage between terminals VPTK and EPTK 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. Turn the ignition switch ON. Measure the voltage between terminals PTNK and EPTK of ECM connector E5. See Figure. Disconnect the vacuum hose from the vapor pressure sensor. Using the MITYVAC (hand-held vacuum pump), apply a vacuum of 1.18 in. Hg (30mm Hg) to the vapor pressure sensor. Vacuum applied to vapor pressure sensor must be less than 19.7 in. Hg (500mm Hg). If voltage is 2.9-3.7 volts, then changes to 0.5 volts with vacuum applied, go to step  13. If not, go to next step.
  12. Check the wire harness between the VSV 2-pin connector for pressure switching valve and ECM connector. Disconnect the V12 VSV 2-pin connector for EVAP. See Figure. Disconnect the E5 ECM connector. Check the continuity between the wire harness side connectors between 2-pin connector terminal No. 1 and ECM E5 connector terminal TBP. Continuity should be present. Ensure no continuity is present between 2-pin connector terminal No. 1 or ECM E5 connector terminal TBP and ECM connector E3 terminal E1. See Figure. Check the wire harness between the VSV for pressure switching valve and EFI relay. Inspect EFI No. 2 fuse. Replace as necessary. Disconnect the V12 VSV 2-pin connector. Remove the EFI relay from the engine room No. 2 relay block. Check continuity between wire harness side of 2-pin connector terminal No. 2 and EFI relay terminal No. 3. If continuity is present, replace vapor pressure sensor assembly. If continuity is not present, repair or replace harness or connector.
  13. Turn the ignition switch ON. Check VSV for EVAP function. Connect jumper wire between terminal PRG of the ECM E2 connector and E1 of ECM E3 connector (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. Check that the air flows with difficulty from ports "E" to "F". See Figure. Apply battery voltage across the terminals. Check that air flows without resistance from ports "E" to "F". See Figure. If okay, go to next step. If not okay, replace VSV and charcoal canister. Clean vacuum hoses between throttle body and VSV for EVAP, and VSV for EVAP and charcoal canister.
  15. Check the wire harness between the VSV 2-pin connector for EVAP and ECM connector. Disconnect the V4 VSV 2-pin connector for EVAP. See Figure. Disconnect the ECM E2 connector. Check the continuity between the wire harness side connectors between 2-pin connector terminal No. 1 and ECM E2 connector terminal PRG. Continuity should be present. Ensure no continuity is present between 2-pin connector terminal No. 1 or ECM E2 connector terminal PRG and ECM connector E3 terminal E1. See Figure. Check the wire harness between the VSV for EVAP and EFI relay. Inspect EFI No. 2 fuse. Replace as necessary. Disconnect the V4 VSV 2-pin connector. Remove the EFI relay from the engine room No. 2 relay block. Check continuity between wire harness side of 2-pin connector terminal No. 2 and EFI relay terminal No. 3. If continuity is present, replace ECM. If continuity is not present, repair or replace harness or connector.
  16. Turn the ignition switch ON. Connect jumper wire between terminal CCV of ECM connector E4 and terminal E1 of connector E3, then disconnect jumper wire. When VSV is ON, air from port "E" flows out through port "F". When VSV is OFF, air does not flow from ports "E" to "F". See Figure. If okay, go to step  19. If not okay, go to next step.
  17. Check operation of VSV for CCV by checking that air flows from ports "A" to "B". See Figure. Apply battery positive voltage across the terminals. Check that the air does not flow from ports "A" to "B". See Figure. 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 the wire harness between the VSV 2-pin connector for CCV and ECM connector. Disconnect the V3 VSV 2-pin connector for EVAP. See Figure. Disconnect the ECM E4 connector. Check the continuity between the wire harness side connectors between 2-pin connector terminal No. 1 and ECM E4 connector terminal CCV. Continuity should be present. Ensure no continuity is present between 2-pin connector terminal No. 1 or E4 connector CCV and ECM connector E3 terminal E1. See Figure. Check the wire harness between the VSV for CCV and EFI relay. Inspect EFI No. 2 fuse. Replace as necessary. Disconnect the V3 VSV 2-pin connector. Remove the EFI relay from the engine room No. 2 relay block. Check continuity between wire harness side of 2-pin connector terminal No. 2 and EFI relay terminal No. 3. If continuity is present, replace ECM. If continuity is not present, repair or replace harness or connector.
  19. Turn the ignition switch ON. Connect jumper wire between terminal TBP of the ECM E5 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  22. If not okay, go to next step.
  20. Check operation of VSV for pressure switching valve. Check that the air flows with difficulty from ports "E" to "F". See Figure. Apply battery positive voltage across the terminals. Check that air flows from ports "E" to "F". See Figure. 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 the wire harness between the VSV 2-pin connector for pressure switching valve and ECM connector. Disconnect the V12 VSV 2-pin connector for EVAP. See Figure. Disconnect the E5 ECM connector. Check the continuity between the wire harness side connectors between 2-pin connector terminal No. 1 and ECM E5 connector terminal TBP. See Figure. Continuity should be present. Ensure no continuity is present between 2-pin connector terminal No. 1 or terminal TBP E5 connector and connector E3 terminal E1. Check the wire harness between the VSV for pressure switching valve and EFI relay. Inspect EFI No. 2 fuse. Replace as necessary. Disconnect the V12 VSV 2-pin connector. Remove the EFI relay from the engine room No. 2 relay block. Check continuity between wire harness side of 2-pin connector terminal No. 1 and EFI relay terminal No. 3. If continuity is present, replace ECM. If continuity is not present, repair or replace harness or connector.
  22. Check fuel tank over fill check valve by disconnecting purge line hose and EVAP line hose from the charcoal canister. Plug the cap to the air drain hose. Apply .58 psi (4 kPa) of pressure to the purge port and check that there is ventilation in the EVAP line. Check if there is anything stuck in the purge line hose and EVAP line hose. If there is nothing stuck in hoses, replace fuel cut off valve and over fill check valve. Reconnect purge line hose and EVAP line hose to charcoal canister. If okay, replace charcoal canister.
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