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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 (Using Hand-Held Tester)

Diagnosis & Repair (Using Hand-Held Tester)

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. Connect the hand-held tester to the DLC3. Select the ENHANCED OBD2/SYSTEM CHECK/EVAP SYS CHECK (or EVAP LEAK TEST) mode on hand-held tester. Perform EVAP SYS CHECK (or EVAP LEAK TEST). If scan tool detects a leak on the fuel tank side or canister side, go to DTC P0441 OR DTC P0446 . If scan tool detects a leak on EVAP system, go to next step.
  2. Check that fuel tank cap is genuine Lexus parts. Replace as necessary. If okay, go to next step.
  3. Check that fuel tank cap is correctly installed. Replace as necessary. If okay, go to next step.
  4. Check fuel tank cap. Replace as necessary. If okay, go to next step.
  5. Check filler neck for damage. Replace as necessary. If okay, go to next step.
  6. Connect the hand-held tester to the DLC3. Select the ACTIVE TEST mode on the hand-held tester. Disconnect the vacuum hose for the VSV for the EVAP from the charcoal canister. Start the engine. Select the item EVAP (ALON)/ALL in the ACTIVE TEST and operate VSV for EVAP. When the VSV for the EVAP is operated by the hand-held tester, check whether the disconnected hose applies, suction to your finger. With VSV ON, disconnected hose applies suction to your finger. With VSV OFF, disconnected hose applies no suction to your finger. See Figure. If okay, go to step  10. If not okay, go to next step.
  7. Check vacuum hose between intake manifold and VSV for EVAP, and VSV for EVAP and charcoal canister. Check that the vacuum hose is connected correctly. Check the vacuum hose for looseness and disconnection. Check the vacuum hose for cracks, hole and damage. Repair as necessary. If okay, go to next step.
  8. Remove EVAP VSV. Using ohmmeter, measure resistance between VSV terminals. With VSV temperature at 68°F (20°C), resistance should be 30-34 ohms. Measure resistance between each terminal and body of valve. Resistance should be infinite. If resistance is as specified, using fused jumper wires, apply battery voltage and ground to EVAP VSV terminals. Apply compressed air to EVAP VSV port "E". Air should flow from port "F". See Figure. Disconnect fused jumper wires. Air should not flow from port "F". If EVAP VSV does not operate as specified, or if resistance was not as specified, replace EVAP VSV and charcoal canister. After replacing components, clean vacuum hoses between EVAP VSV and throttle body, and between EVAP VSV and charcoal canister. If EVAP VSV operates as specified, go to next step. Replace as necessary. If okay, go to next step.
  9. 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 as necessary. If okay, replace ECM.
  10. Connect the hand-held tester to the DLC3. Disconnect the vacuum hose for the VSV for the CCV from the charcoal canister. Turn the ignition switch ON and push the hand-held tester main switch ON. Select ACTIVE TEST mode on hand-held tester. Check the VSV operation when it is operated by the hand-held tester. 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  14. If not okay, go to next step.
  11. Check vacuum hose between VSV for CCV and charcoal canister. Repair as necessary. If okay, go to next step.
  12. 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 VSV does not operate as specified, or if resistance was not as specified, replace VSV. If VSV is okay, go to next step.
  13. 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.
  14. Connect the hand-held tester to the DLC3. Turn the ignition switch ON and push the hand-held tester main switch ON. Select the ACTIVE TEST mode on the hand-held tester. Check the VSV operation when it is operated by the hand-held tester. If VSV is ON, air from port "E" flows out through port "F". If VSV is OFF, air does not flow from port "E" to port "F". See Figure. If okay, go to step  17. If not okay, go to next step.
  15. Check operation of VSV for pressure switching valve. Using ohmmeter, measure resistance between VSV terminals. With VSV temperature at 68°F (20°C), resistance should be 37-44 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 "E". Air should not flow from port "F". Using fused jumper wires, apply battery voltage and ground to VSV terminals. Air should flow from port "F". See Figure. If VSV does not operate as specified, or if resistance was not as specified, replace VSV. If VSV is okay, go to next step.
  16. 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.
  17. Check whether hose close to fuel tank has been modified, and check whether there are signs of any accident near fuel tank. See Figure. Repair as necessary. If okay, go to next step.
  18. Check vacuum hoses 4, 5, 7 and 8. See Figure. Repair as necessary. If okay, go to next step.
  19. 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.
  20. Check charcoal canister for cracks, holes and damage. Replace as necessary. If okay, go to next step.
  21. Remove the engine room ECU cover. Turn the ignition switch ON. Measure the voltage between terminals VPTK and EPTK of the ECM connector. See Figure. If voltage is 4.5-5.5 volts, go to next step. If not, replace ECM.
  22. 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 (30 mm Hg ) to the vapor pressure sensor. 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 with vacuum hose disconnected or 0.5 volts or less with vacuum applied, go to step  24. If not, go to next step.
  23. Check for open and short in harness and connector between vapor pressure sensor and ECM. Repair as necessary. If okay, go to next step.
  24. Check for open and short in harness and connector between vapor pressure sensor and ECM. Repair as necessary. If okay, replace vapor pressure sensor.
  25. Check fuel tank and fuel tank over fill check valve for cracks and damage. Replace fuel tank or fuel tank over fill check valve. It is possible that vehicle user did not properly close fuel tank cap.
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