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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 98 (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 LS 430. 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. 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. 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. Remove the engine room ECU cover. 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. Measure the voltage between terminals PTNK and EPTK of the ECM connectors. 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 (4.0 kPa) to the vapor pressure sensor. Vacuum applied to vapor pressure sensor must be less than 19.7 in. Hg (66.7 kPa). If voltage is 2.9-3.7 volts with vacuum hose disconnected or less than 0.5 volts with vacuum applied, 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 PRG 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. 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 main 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. Using ohmmeter, measure resistance between VSV terminals. With VSV temperature at 68°F (20°C), resistance should be 25-30 ohms. Measure resistance between each terminal and body of valve. Resistance should be infinite. If resistance is as specified, apply air to EVAP VSV port "A". Air should flow from port "B". See Figure. Using fused jumper wires, apply battery voltage and ground to VSV terminals. No air should flow from port "B". 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 main 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, go to step  22. If not okay, go to next step.
  20. Check operation of VSV for pressure switching valve. 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 main relay and VSV for pressure switching valve, and VSV for pressure switching valve and ECM. Repair as necessary. If okay, check and replace ECM.
  22. Check fuel tank over fill check valve. See Figure and Figure . Replace as necessary. If okay, replace charcoal canister.
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