LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 1997 >> Swift Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes (DTC) >> DTC P0440: Evaporative (EVAP) Emission Control System Malfunction
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0440: Evaporative (EVAP) Emission Control System Malfunction

NOTE: PCM may stop purge operation when EVAP hoses are disconnected with engine running. This is a normal condition due to a change in purge gas concentration detected by PCM.
  1. Ensure fuel filler cap is tight. Tighten or replace cap if necessary. Check vacuum hoses for leaks and proper routing. Repair as necessary. Go to next step.
  2. Ensure engine is cool. Disconnect purge hose from EVAP canister. Place a finger against end of disconnected hose. Start engine and let idle. Vacuum should not be felt at hose when engine is cool. Allow engine to reach normal operating temperature. Vacuum should now be present at purge hose. If operation is as specified, go to next step. If operation is not as specified, go to step 12).
  3. Disconnect canister air valve hose from EVAP canister. Turn ignition on. Using a fused jumper wire, backprobe PCM harness connector "A", terminal No. 3 to ground. See Fig 1 . Blow air into port "A" of canister air valve. Air should not pass through valve. Turn ignition off and remove jumper wire. Air should pass through port "B". If operation is as specified, go to next step. If operation is not as specified, go to step 14).
    Fig 1: Identifying EVAP Canister Air Valve Ports
    G96A11189Courtesy of SUZUKI OF AMERICA CORP.
  4. Check fuel tank pressure control valve for proper operation. Repair as necessary. If operation is as specified, go to next step.
  5. Disconnect vacuum hoses from EVAP canister. Blow air into tank pipe. Air should flow through purge pipe and air pipe with no restriction. If operation is as specified, go to next step. If operation is not as specified, replace EVAP canister.
  6. Reconnect hoses to EVAP system parts, leaving hoses disconnected from intake manifold. Turn ignition on. Using a fused jumper wire, backprobe PCM harness connector "A", terminal No. 7 to ground. Plug canister air valve hose end. See Fig 2 . Go to next step.
    Fig 2: Checking EVAP System For Leaks
    G96E11191Courtesy of SUZUKI OF AMERICA CORP.
  7. Disconnect tank hose from tank pressure control valve and plug tank port of valve. Apply 0.5 psi (0.04 kg/cm2 ) into purge line and seal it. If pressure holds at least 0.48 psi (0.03 kg/cm2 ), go to next step. If pressure does not hold as specified, locate leak using soapy water or electronic leak detector. Repair as necessary. Retest system.
  8. Disconnect hose from tank pressure control valve. Turn ignition on. Using a fused jumper wire, backprobe PCM harness connector "A", terminal No. 19 to ground. Blow air into port "A" of tank pressure control vacuum valve. See Fig 3 . Air should flow through port "B" and not through filter. Turn ignition off and remove jumper wire. Air should flow through filter and not port "B". If operation is as specified, go to next step. If operation is not as specified, go to step 16).
    Fig 3: Identifying Tank Pressure Control Solenoid Vacuum Valve Ports
    G96G11193Courtesy of SUZUKI OF AMERICA CORP.
  9. Disconnect tank hose from tank pressure control valve. Apply 0.5 psi (0.04 kg/cm2 ) into fuel tank and seal it. If pressure holds at least 0.48 psi (0.03 kg/cm2 ), go to next step. If pressure does not hold as specified, locate leak using soapy water or electronic leak detector. Removal of fuel tank may be necessary. Repair as necessary. Retest system.
  10. Check fuel tank pressure sensor performance. See SYSTEM/COMPONENT TESTS article. Repair as necessary. If operation is as specified, go to next step.
  11. Check fuel level sensor and circuit following procedures in DTC P0461  . If vehicle is equipped with a tachometer, check Black/Blue wire for short to ground. Repair as necessary. If operation is as specified, check for an intermittent problem. See TESTS W/O CODES article.
  12. Turn ignition off. Disconnect harness connector from canister purge valve. Using an ohmmeter, measure resistance between canister purge valve terminals. Resistance should be 33-39 ohms at 68°F (20°C). Resistance between each terminal and body of valve should be one megohm or greater. If resistance is as specified, check White/Blue wire and Red/Green wire between valve and PCM for an open or short. Repair as necessary. If wires are okay, replace PCM. Retest system. If resistance is not as specified, replace canister purge valve.
  13. Disconnect vacuum hoses from canister purge valve. Blow air into port "A". See Fig 4 . Air should not flow through valve. Connect a 12-volt battery and ground to terminals of valve. Air should pass through port "B". If operation is not as specified, replace canister purge valve.
    Fig 4: Identifying EVAP Canister Purge Valve Ports
    G96C09898Courtesy of SUZUKI OF AMERICA CORP.
  14. Turn ignition off. Disconnect harness connector from canister air valve. Using an ohmmeter, measure resistance between canister air valve terminals. Resistance should be 25-30 ohms at 68°F (20°C). Resistance between each terminal and body of valve should be one megohm or greater. If resistance is as specified, go to next step. If resistance is not as specified, replace canister air valve.
  15. Disconnect vacuum hoses from canister air valve. Blow air into port "A". See Fig 1 . Air should flow through port "B". Connect a 12-volt battery and ground to terminals of valve. Air should not pass through port "B". If operation is not as specified, replace canister air valve. If operation is as specified, check White/Blue wire and Red/White wire between valve and PCM for an open or short. Repair as necessary. If wires are okay, replace PCM. Retest system.
  16. Turn ignition off. Disconnect harness connector from tank pressure control solenoid vacuum valve. Using an ohmmeter, measure resistance between solenoid terminals. Resistance should be 33-39 ohms at 68°F (20°C). Resistance between each terminal and body of solenoid should be one megohm or greater. If resistance is as specified, go to next step. If resistance is not as specified, replace tank pressure control solenoid vacuum valve.
  17. Disconnect vacuum hoses from tank pressure control solenoid vacuum valve. Blow air into port "A". See Fig 3 . Air should not flow through valve. Connect a 12-volt battery and ground to terminals of valve. Air should pass through port "B". If operation is not as specified, replace tank pressure control vacuum valve. If operation is as specified, check White/Blue wire and Red/Green wire between valve and PCM for an open or short. Repair as necessary. If wires are okay, replace PCM. Retest system.
scientia non olet · About LEMON Manuals