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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 106 (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 (Using OBD-II Scan Tool)
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Diagnosis & Repair (Using OBD-II Scan Tool)

WARNING: This page is about a different car, the 2003 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check that fuel tank cap is a Lexus part. Replace as necessary. If okay, go to next step.
  2. Ensure fuel cap is correctly installed. Correctly install 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. Repair 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. 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 or connect VSV or sensor connector 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 EVAP pipe, fuel EVAP pipe and fuel tube under the floor, fuel tube under the floor and charcoal canister. Check the hose and tube for cracks, holes and damage. 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 or connect VSV or sensor connector 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 ECM hood. Turn the ignition switch ON. Measure the voltage between terminals VC and E2 of ECM connector E5. 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. Measure voltage between terminals PTNK and E2 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. (30 mm Hg) to the vapor pressure sensor. Vacuum applied to vapor pressure sensor must be less than 19.7 in.(500 mm Hg). If voltage is 2.9-3.7 volts with vacuum hose disconnected, and .5 volts or less 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 ECM connector E2 and ground, then disconnect wire. 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.
  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 as necessary. If okay, replace ECM.
  16. Check the VSV function. Connect jumper wire between terminal CCV of the ECM connector E4 and body ground, then disconnect wire. 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 step  12 under DIAGNOSIS & REPAIR (USING HAND-HELD TESTER). If okay, go to next step. If not okay, replace VSV and charcoal canister. 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 or replace harness or connector as necessary. If okay, replace ECM.
  19. Check VSV function by connecting jumper wire between terminal TBP of the ECM connector E5 and body ground, then disconnect wire. 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. See step  15 under DIAGNOSIS & REPAIR (USING HAND-HELD TESTER). 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, replace ECM.
  22. Check fuel tank over fill check valve. Check fuel tank overfill check valve by disconnecting purge line hose and EVAP line hose from the charcoal canister. Disconnect air drain hose from the canister tank, and plug end. Pressurize .58 psi to purge port and ensure there is ventilation through EVAP line hose. If fuel tank is full, as float value of fill check valve is closed and has no ventilation, it is necessary to check fuel volume. Check if there is anything stuck in vent line hose and EVAP line hose. If there is nothing stuck in hoses, replace fuel cutoff valve and fill check valve. Reconnect purge line hose and EVAP line hose to the charcoal canister. Reconnect the air drain hose to the canister tank. If okay, replace charcoal canister.
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