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Home >> Toyota >> 2000 >> MR2 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P0440: Evaporative Emission Control System >> Diagnosis & Repair

Diagnosis & Repair

  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 on driver's side of firewall behind driver's seat, luggage compartment lids and partition board. See Figure. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM harness connector E4. See Figure. Voltage should be 4.5-5.5 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace ECM.
  10. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 4 (Green/Black wire) at ECM harness connector E2 and terminal No. 18 (Brown wire) at ECM harness connector E4. Remove fuel tank cap. Turn ignition on. 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 for damage. 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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