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Diagnosis & Repair (Using Hand-Held Tester)

WARNING: This page is about a different car, the 2003 Lexus RX 300. 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 the hand-held tester. Perform EVAP SYS CHECK (or EVAP LEAK TEST). Check display on hand-held tester. If scan tool detects a leak on the fuel tank side, go to next step. If scan tool detects a leak on the canister side, go to step  24. If scan tool detects a leak on the EVAP system, go to step  42.
  2. Check if fuel tank cap is an original manufacturer's cap. If fuel tank cap is an original manufacturer's cap, go to next step. If fuel tank cap is not an original manufacturer cap, replace cap with a manufacturer's cap.
  3. Check if fuel cap is installed properly. Reinstall cap as necessary. If fuel cap is installed properly, go to next step.
  4. Check for damaged fuel tank cap and gasket. Replace fuel tank cap as necessary. If fuel tank cap and gasket are okay, go to next step.
  5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. Replace filler neck as necessary. If filler neck is okay, go to next step.
  6. Connect the hand-held tester to the DLC3. Select the ENHANCED OBD2/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 EVAP (ALON)/ALL in the ACTIVE TEST and operate VSV for EVAP. Check when VSV for EVAP is operated by the hand-held tester, and check whether disconnected hose applies suction to your finger. If system is okay, VSV is ON and disconnected hose applies suction to your finger. If VSV is OFF, disconnected hose applies no suction to your finger. See Fig 1. If system operates, go to step  10. If system does not operate, go to next step.
    Fig 1: Checking VSV Operation
    G00165068Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. Check vacuum hoses between intake manifold and VSV for EVAP, and VSV for EVAP and charcoal canister. Check hoses for correct installation, looseness and damage. Repair as necessary. If vacuum hoses are okay, go to next step.
  8. Check operation of VSV for EVAP. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Replace VSV for EVAP as necessary. If okay, go to next step.
  9. Check for open and short in harness and connector between EFI relay and VSV for EVAP, and VSV for EVAP and ECM. Repair as necessary. If okay, check and replace ECM.
  10. Turn ignition off. Disconnect the vacuum hose for the VSV from the charcoal canister. Turn the ignition switch ON and push the hand-held tester main switch ON. Select ENHANCED OBD2/ACTIVE TEST mode on the hand-held tester. Select the item INTAKE CTL VSV/ALL in the ACTIVE TEST and operate VSV for EVAP. Check the VSV operation when it is operated by the hand-held tester. If VSV is ON, air does not flow from port "E" to port "F". If VSV is OFF, air from port "E" flows out through port "F". See Fig 2. If okay, go to step  14. If not okay, go to next step.
    Fig 2: Checking VSV For CCV
    G00165069Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  11. Check for correct routing, looseness, damage and blockage in vacuum hoses between canister closed valve VSV and charcoal canister. Repair as necessary. If hose is okay, go to next step.
  12. Check canister closed valve VSV. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If canister closed valve VSV is not okay, replace canister closed valve VSV and charcoal canister. Also clean vacuum hoses between charcoal canister and canister closed valve VSV. If canister closed valve VSV is okay, go to next step.
  13. Check for an open or short in wiring harness between EFI main relay, canister closed valve VSV and ECM. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary. If wiring is okay, replace ECM and retest system.
  14. Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Ensure ignition is on. Select ENHANCED OBD2/ACTIVE TEST mode on scan tool. Select item TANK BYPASS VSV/ALL in ACTIVE TEST and operate VSV for EVAP. Check VSV operation when it is operated by 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 Fig 3. If okay, go to step  17. If not okay, go to next step.
    Fig 3: Checking VSV For Pressure Switching Valve
    G00165070Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  15. Check pressure switching valve VSV. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. If pressure switching valve VSV is not okay, replace pressure switching valve VSV. If pressure switching valve VSV is okay, go to next step.
  16. Check for an open or short in wiring harness between EFI main relay and VSV for pressure switching valve, and VSV for pressure switching valve and ECM. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary. If wiring is okay, replace ECM and retest system.
  17. Check for cracks, deformation and loose connection of fuel tank, fuel tank filler pipe, and hoses and tubes around fuel tank. See Fig 4. If okay, go to next step. If not okay, repair as necessary.
    Fig 4: Checking For Cracks, Deformation & Loose Connections
    G00165071Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  18. Check vacuum hoses between vapor pressure sensor and fuel tank, and charcoal canister and VSV for pressure switching valve. Ensure vacuum hose is connected correctly and for cracks, holes and damage. Repair as necessary. If okay, go to next step.
  19. Check for proper connection of fuel tank and fuel evaporation pipe, fuel evaporation pipe and fuel tube under floor, fuel tube under floor and charcoal canister. Check hose and tube for cracks, holes and damages. Repair or replace as necessary. If okay, go to next step.
  20. Access ECM behind glove box. Turn the ignition switch ON. Measure the voltage between terminals VC and E2 of the ECM connector. See Fig 5. Voltage should be 4.5-5.5 volts. If okay, go to next step. If not okay, replace ECM.
    Fig 5: Checking Voltage At Terminals VC & E2
    G00165072Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  21. Access ECM behind glove box. Turn the ignition switch ON. Backprobing ECM harness connector, connect DVOM between terminals. Measure the voltage between terminals PTNK and E2 of ECM connectors. Disconnect the vacuum hose from the vapor pressure sensor. Using the MITYVAC (Hand-Held Vacuum Pump), apply a vacuum of 4.0 kPa (30 mm Hg, 1.18 in. Hg) to the vapor pressure sensor. Vacuum applied to the vapor pressure sensor must be less than 66.7 kPa (500 mm Hg, 19.7 in. Hg). If voltage is 2.9-3.7, or 0.5 volts or less, go to step  23. If not, go to next step.
    Fig 6: Checking Voltage At Terminals E2 & PTNK At ECM Connector
    G00165073Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  22. Check for open or short in harness and connector between vapor pressure sensor and ECM. Repair as necessary. If okay, replace vapor pressure sensor.
  23. Check fuel tank and fuel tank overfill check valve for cracks and damage. Repair as necessary. If okay, it is possible that fuel cap was not properly closed at one time.
  24. Connect the hand-held tester to the DLC3. Select the ENHANCED OBD2/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. When VSV is ON, disconnected hose applies suction to your finger. When VSV is OFF, disconnected hose applies no suction to your finger. See Fig 1. If system is okay, go to step  28. If system is not okay, go to next step.
  25. 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, holes, damage and blockages. Repair as necessary. If okay, go to next step.
  26. Check operation of VSV for EVAP. See SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Replace as necessary. If okay, go to next step.
  27. Check for open and short in harness and connector between EFI relay and VSV for EVAP, and VSV for EVAP and ECM. If okay, check and replace ECM. If not okay, repair or replace harness or connector.
  28. 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 the ENHANCED OBD2/ACTIVE TEST mode on the hand-held tester. Select INTAKE CTL VSV/ALL in the ACTIVE TEST and operate VSV for EVAP. 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 Fig 2. If okay, go to step  32. If not okay, go to next step.
  29. Check vacuum hose between VSV for CCV 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, holes damage, and blockages. Repair or replace as necessary. If okay, go to next step.
  30. Check operation of VSV for CCV. See SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Replace VSV for CCV as necessary. If okay, go to next step.
  31. Check for open and short in harness and connector between EFI relay and VSV for CCV, and VSV for CCV and ECM. Repair or replace harness or connector as necessary. If okay, check and replace ECM.
  32. Turn the ignition switch ON and push the hand-held tester main switch ON. Select the ENHANCED OBD2/ACTIVE TEST mode on the hand-held tester. Select the item TANK BYPASS VSV/ALL in the ACTIVE TEST and operate VSV for EVAP. 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 Fig 3. If okay, go to step  35. If not okay, go to next step.
  33. Check operation of VSV for pressure switching valve. See SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Replace as necessary. If okay, go to next step.
  34. Check for open and short in harness and connector between EFI relay and VSV for pressure switching valve, and VSV for pressure switching valve and ECM. If not okay, repair or replace harness or connector. If okay, check and replace ECM.
  35. Check for cracks, deformation and loose connection of charcoal canister and hoses and tubes around charcoal canister. See Fig 4. Repair or replace as necessary. If okay, go to next step.
  36. Check that vacuum hoses are connected correctly. Check vacuum hoses for looseness and disconnection. Check the vacuum hoses for cracks, holes and damages. Repair or replace as necessary. If okay, go to next step.
  37. 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. Check the hose and tube for cracks, holes and damages. Repair or replace as necessary. If okay, go to next step.
  38. Check charcoal canister for cracks, holes and damage. Repair or replace as necessary. If okay, go to next step.
  39. Remove the glove compartment. Turn the ignition switch ON. Measure the voltage between terminals VC and E2 of the ECM connector. See Fig 5. If okay, voltage should be 4.5-5.5 volts. Go to next step. If not okay, check and replace ECM.
  40. Remove the glove compartment. Turn the ignition switch ON. 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 (4.0 kPa, 30 mm Hg) to the vapor pressure sensor. The vacuum applied to the vapor pressure sensor must be less than 19.7 in. Hg (66.7 kPa, 500 mm Hg). Voltage should be 2.9-3.7 volts, or 0.5 volts or less. See Fig 6. If voltage is okay, check and replace ECM. If voltage is not okay, go to next step.
  41. Check for open and short in harness and connector between vapor pressure sensor and ECM. Repair or replace harness or connector as necessary. If okay, replace vapor pressure sensor.
  42. Connect the hand-held tester to the DLC3. Select the ENHANCED OBD2/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 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. When VSV is ON, disconnected hose applies suction to your finger. When VSV is OFF, disconnected hose applies no suction to your finger. See Fig 1. If okay, go to step  46. If not okay, go to next step.
  43. 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, holes, damage and blockages. Repair or replace as necessary. If okay, go to next step.
  44. Check operation of VSV for EVAP. See SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Replace VSV for EVAP as necessary. If okay, go to next step.
  45. Check for open and short in harness and connector between EFI relay and VSV for EVAP, and VSV for EVAP and ECM. Repair or replace harness or connector. If okay, check and replace ECM.
  46. 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 the ENHANCED OBD2/ACTIVE TEST mode on the hand-held tester. Select the item INTAKE CTL VSV/ALL in the ACTIVE TEST and operate VSV for EVAP 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 Fig 2. If okay, go to step  50. If not okay, go to next step.
  47. Check vacuum hose between VSV for CCV 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, holes damage, and blockages. Repair or replace as necessary. If okay, go to next step.
  48. Check operation of VSV for CCV. See SYSTEM & COMPONENT TESTING - ES300 & RX300 article. If not okay, replace VSV for CCV. If okay, go to next step.
  49. Check for open and short in harness and connector between EFI relay and VSV for CCV, and VSV for CCV and ECM. Repair or replace harness or connector. If okay, check and replace ECM.
  50. Turn the ignition switch ON and push the hand-held tester main switch ON. Select the ENHANCED OBD2/ACTIVE TEST mode on the hand-held tester. Select the item TANK BYPASS VSV/ALL in the ACTIVE TEST and operate VSV for EVAP CHECK. Check the VSV operation when it is operated by the hand-held tester. 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 Fig 3. If okay, go to step  53. If not okay, go to next step.
  51. Check operation of VSV for pressure switching valve. Replace VSV for pressure switching valve as necessary. If okay, go to next step.
  52. Check for open and short in harness and connector between EFI relay and VSV for pressure switching valve, and VSV for pressure switching valve and ECM. Repair or replace harness or connector. If okay, check and replace ECM.
  53. 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 Fig 4. Repair or replace as necessary. If okay, go to next step.
  54. Check vacuum hoses between vapor pressure sensor and fuel tank, and charcoal canister and VSV for pressure switching valve. Check that the vacuum hose is connected correctly. Check the vacuum hose for looseness and disconnection. Check the vacuum hose for cracks, holes and damages. Repair or replace as necessary. If okay, go to next step.
  55. Check vacuum hoses. Check that the vacuum hose is connected correctly. Check the vacuum hose for looseness and disconnection. Check the vacuum hose for cracks, holes and damages. Repair or replace as necessary. If okay, go to next step.
  56. Remove the glove compartment. Turn the ignition switch ON. Measure the voltage between terminals VC and E2 of the ECM connector. See Fig 5. If voltage is 4.5-5.5 volts, go to next step. If voltage is not to specification, check and replace ECM.
  57. Remove the glove compartment. Turn the ignition switch ON. 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 (4.0 kPa, 30 mm Hg) to the vapor pressure sensor. See Fig 6. Vacuum applied to the vapor pressure sensor must be less than 19.7 in. Hg (66.7 kPa, 500 mm Hg). If okay, voltage should be 2.9-3.7 volts, or 0.5 volts or less. Check and replace ECM. If voltage is not okay, go to next step.
  58. Check for open and short in harness and connector between vapor pressure sensor and ECM. Repair or replace harness or connector. If okay, replace vapor pressure sensor.
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