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Home >> Acura >> 1997 >> 2.5TL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0440: EVAP Control System Leak Detected
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DTC P0440: EVAP Control System Leak Detected

  1. If DTC P0440 is set, check:
    • Vacuum connections.
    • Fuel tank or fuel filler cap.
    • EVAP control canister vent shut valve.
    • EVAP control canister vent shut valve circuit.
    • EVAP purge control solenoid valve.
    • EVAP purge control solenoid valve circuit.
    • EVAP bypass solenoid valve.
    • EVAP bypass solenoid valve circuit.
    • Fuel tank pressure sensor.
    • Fuel tank pressure sensor circuit.
    • EVAP control canister.
    • Throttle body.

    Repair as necessary. If no problems are found, go to next step.

  2. Disconnect EVAP control canister vent shut valve vacuum hose from EVAP three-way valve located on side of EVAP control canister. See Fig 1 . Turn ignition on. Apply vacuum to EVAP control canister vent shut valve vacuum hose. If EVAP control canister vent shut valve holds vacuum, go to next step. If valve does not hold vacuum, go to step 4).
  3. Turn ignition off. Disconnect EVAP control canister vent shut valve 2-pin connector. Turn ignition on. Apply vacuum to EVAP control canister vent shut valve hose. See Fig 1 . If valve does not hold vacuum, repair short in Yellow/Blue wire between EVAP control canister vent shut valve and PCM 26-pin connector terminal No. 23. See the WIRING DIAGRAMS article. If valve holds vacuum, replace EVAP control canister vent shut valve.
    Fig 1: Testing EVAP Vent Shut Valve
    G96D01355Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Turn ignition off. Connect a jumper wire between ground and PCM 26-pin connector terminal No. 23 (Yellow/Blue wire). Turn ignition on. Apply vacuum to EVAP control canister vent shut valve hose. If EVAP control canister vent shut valve does not hold vacuum, go to next step. If valve holds vacuum, go to step 7).
  5. Turn ignition off. Disconnect EVAP control canister vent shut valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP control canister vent shut valve 2-pin connector terminal No. 1 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between EVAP control canister vent shut valve and ECU fuse No. 4 (20-amp) in underdash fuse/relay box. See the WIRING DIAGRAMS article.
  6. Turn ignition off. Reconnect EVAP control canister vent shut valve 2-pin connector. Turn ignition on. Measure voltage between PCM 26-pin connector terminals No. 12 (Black wire) and No. 23 (Yellow/Blue wire). If battery voltage is present, replace EVAP control canister vent shut valve. If battery voltage is not present, repair open in Yellow/Blue wire between EVAP control canister vent shut valve and PCM. See the WIRING DIAGRAMS article.
  7. Disconnect upper vacuum hose from EVAP control canister diaphragm and connect a vacuum gauge to hose (should be routed from EVAP purge control solenoid valve). Ensure engine coolant temperature is less than 167°F (75°C). Start engine and allow to idle. Quickly increase engine speed to 3000 RPM. If vacuum exists, allow engine to idle and go to next step. If vacuum does not exist, turn engine off and go to step 10).
  8. Disconnect EVAP purge control solenoid valve 2-pin connector. Quickly increase engine speed to 3000 RPM. If vacuum does not exist, go to next step. If vacuum exists, inspect for proper vacuum hose routing. If hose routing is okay, replace EVAP purge control solenoid valve.
  9. Turn ignition off. Disconnect PCM 26-pin connector. See Figure . Check for continuity between ground and EVAP purge control sole noid valve 2-pin connector terminal No. 1 (Red/Yellow wire). If continuity exists, repair short in Red/Yellow wire. If continuity does not exist, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  10. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral, until radiator fan comes on. Allow engine to idle. Quickly increase engine speed to 3000 RPM. Check for vacuum at hose routed from EVAP purge control solenoid valve to EVAP control canister. If vacuum does not exist, go to next step. If vacuum exists, go to step 14).
  11. Turn ignition off. Disconnect EVAP purge control solenoid valve 2-pin connector. Start engine. Measure voltage between harness side of EVAP purge control solenoid valve 2-pin connector terminal No. 1 (Red/Yellow wire) and No. 2 (Black/Yellow wire). If battery voltage is not present, go to next step. If battery voltage is present, inspect for proper vacuum hose routing. If hose routing is okay, replace EVAP purge control solenoid valve.
  12. Measure voltage between ground and EVAP purge control solenoid valve 2-pin connector terminal No. 2 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between EVAP purge control solenoid valve and ECU fuse No. 4 (20-amp) in underdash fuse/relay box.
  13. Turn ignition off. Reconnect EVAP purge control solenoid valve 2-pin connector. Turn ignition on. Measure voltage between PCM 26-pin connector terminals No. 12 (Black wire) and No. 18 (Red/Yellow wire). If battery voltage is not present, repair open in Red/Yellow wire between EVAP purge control solenoid valve and PCM. If battery voltage is present, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  14. Check EVAP two-way valve. See the SYSTEM/COMPONENT TESTS article. If two-way valve is okay, go to next step. Replace two-way valve if it is not okay.
  15. Turn ignition off. Disconnect EVAP two-way valve lower hose. Turn ignition on and apply vacuum to EVAP two-way valve lower hose port. If valve does not hold vacuum, go to next step. If valve holds vacuum, go to step 17).
  16. Disconnect EVAP bypass solenoid valve 2-pin connector. If EVAP two-way valve holds vacuum, repair short in White/Blue wire between EVAP bypass solenoid valve and PCM 26-pin connector terminal No. 24. If EVAP two-way valve does not hold vacuum, replace EVAP bypass solenoid valve.
  17. Turn ignition off. Connect a jumper wire between ground and PCM 26-pin connector terminal No. 24 (White/Blue wire). Turn ignition on. If valve holds vacuum, go to next step. If EVAP two-way valve does not hold vacuum, check for leaks to atmosphere in the following components:
    • Fuel tank and fuel filler cap.
    • Fuel vapor line.
    • EVAP two-way valve.
    • EVAP bypass solenoid valve.
    • Fuel tank pressure sensor.
    • EVAP control canister.
    • EVAP control canister vent shut valve.
    • EVAP purge control solenoid valve.
    • Vacuum hoses and connections.

    Repair as necessary. If no problems are found, go to next step.

  18. Turn ignition off. Disconnect EVAP bypass solenoid valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP bypass solenoid valve 2-pin connector terminal No. 1 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between ECU fuse No. 4 (20-amp) and EVAP bypass solenoid valve.
  19. Turn ignition off. Reconnect EVAP bypass solenoid valve 2-pin connector. Turn ignition on. Measure voltage between PCM 26-pin connector terminals No. 12 (Black wire) and No. 24 (White/Blue wire). If battery voltage is present, replace EVAP bypass solenoid valve. If battery voltage is not present, repair White/Blue wire between EVAP bypass solenoid valve and PCM.
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