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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Control System Self-Diagnostics - 4-Cylinder) >> Diagnostic Tests >> DTC P0440: Evaporative Emission Control System, Or DTC P0442: Evaporative Emission Control System Leak Detected >> Diagnosis & Repair

Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If DTC P0441, DTC P0446, DTC P0450 or DTC P0451 is output after DTC P0440 or DTC P0442, perform appropriate test first before performing this test.
  1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
  3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
  4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
  5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem does not exist, go to next step. If problem exists, replace fuel tank filler pipe as necessary.
  6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
  7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
  8. Check charcoal canister for damage. If problem does not exist, go to next step. If problem exists, repair or replace as necessary.
  9. Access ECM behind glove box. See Figure. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. 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.
  10. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 21 (Blue/Black wire) at ECM harness connector E6 and terminal No. 18 (White wire) at ECM harness connector E8. See Figure. Remove fuel tank cap. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step  12.
  11. Check for an open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  12. Check fuel tank and fuel tank overfill valve. If problem exists, repair or replace fuel tank or fuel tank overfill valve as necessary. If problem does not exist, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.
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