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DTC P0440 - Evaporative (EVAP) Control System Malfunction

NOTE: Ensure fuel filler cap is tightened securely before testing EVAP system.
  1. Raise and support vehicle. Place transmission in Neutral, and transfer case in 2H. Start engine. Ensure rear wheels turn. If wheels do not turn, block one rear wheel and turn other by hand.
  2. Allow engine to reach normal operating temperature. Turn ignition off. Restart engine and raise engine speed to 2000 RPM for 3 minutes.
  3. Return engine to idle. Disconnect purge hose from EVAP canister. Place a finger against end of disconnected hose. Ensure vacuum is not felt with engine at idle. Raise engine speed to greater than 1500 RPM. Vacuum should now be present. If operation is as specified, go to next step. If operation is not as specified, go to step 8).
  4. Disconnect vacuum hose from EVAP canister. With ignition on, blow into port "A" of EVAP canister air valve. See Fig 1. Air should flow through port "B". Turn ignition off. Using a fused jumper wire, connect (backprobe) PCM harness connector "B", terminal No. 6 (Green/White wire) to ground. See Figure. Turn ignition on. Blow into port "A". Air should not flow through port "B". If operation is as specified, go to step 12). If operation is not as specified, go to next step.
    Fig 1: Identifying EVAP Canister Air Valve Ports
    G96A09883Courtesy of SUZUKI OF AMERICA CORP.
  5. Turn ignition off. Disconnect harness connector from EVAP canister air valve. Using an ohmmeter, measure resistance between air valve terminals. If resistance is 25-30 ohms at 68°F (20°C), go to next step. If resistance is not a specified, replace EVAP canister air valve. Retest system.
  6. Ensure hoses are disconnected from EVAP canister air valve. Blow into port "A". Air should not flow through port "B". If operation is as specified, go to next step. If operation is not a specified, replace EVAP canister air valve. Retest system.
  7. Using fused jumper wires, connect a 12-volt battery to EVAP canister air valve terminals. Blow into port "A". Air should flow through port "B". If operation is as specified, check EVAP canister air valve harness for open or short. Repair as necessary. If operation is not as specified, replace EVAP canister air valve. Retest system.
  8. Disconnect vacuum hoses from the intake manifold and the EVAP canister purge valve. With ignition on, blow into port "A". See Fig 2. Air should not flow through port "B". If operation is as specified, replace PCM. If operation is not as specified, go to next step.
    Fig 2: Identifying EVAP Canister Purge Valve Ports
    G96F09885Courtesy of SUZUKI OF AMERICA CORP.
  9. Turn ignition off. Using a fused jumper wire, connect PCM harness connector "B", terminal No. 25 (Light Green/Yellow wire) to ground. Turn ignition on. Blow into port "A". Air should flow through port "B". If operation is as specified, replace PCM. Retest system. If operation is not as specified, go to next step.
  10. Turn ignition off. Disconnect EVAP canister purge valve harness connector. Using an ohmmeter, measure resistance of purge valve. If resistance is 28-36 ohms at 68°F (20°C), go to next step. If resistance is not as specified, replace EVAP canister purge valve. Retest system.
  11. Blow into port "A" of purge valve. Air should not flow through port "B". Using fused jumper wires, connect 12-volt battery to EVAP canister purge valve terminals. Blow into hose "A". Air should pass through port "B". If operation is as specified, check EVAP canister purge valve harness for open or short. Repair as necessary. If operation is not as specified, replace EVAP canister purge valve. Retest system.
  12. Disconnect and remove tank pressure control valve. Air should pass through valve from tank port to EVAP canister port when blown through hard. See Fig 3. Air should pass through valve in opposite direction when blown through softly. If operation is as specified, go to next step. If operation is not as specified, replace tank pressure control valve.
    Fig 3: Identifying Tank Pressure Control Valve Ports
    G96J09887Courtesy of SUZUKI OF AMERICA CORP.
  13. Using a hand-held vacuum pump, apply vacuum to vacuum port of valve. Blow into tank port of valve. Air should pass through EVAP canister port smoothly. If operation is as specified, go to next step. If operation is not as specified, replace tank pressure control valve. Retest system.
  14. Disconnect vacuum hoses from tank pressure control solenoid. Start engine and let idle. Place a finger against end of vacuum hose. If vacuum is present, go to next step. If vacuum is not present, clean vacuum passage or replace vacuum hose. Retest system.
  15. Turn ignition off. Disconnect PCM harness connector "B". Turn ignition on. Blow through port "A". See Fig 4. Air should flow through filter and not port "B". Using a fused jumper wire, connect terminal No. 7 (Green/Blue wire) of PCM harness connector "B" to ground. Blow into port "A". Air should flow through port "B" and not through filter. If operation is as specified, go to step 18). If operation is not as specified, go to next step.
    Fig 4: Identifying Tank Pressure Control Solenoid Ports
    G96D09889Courtesy of SUZUKI OF AMERICA CORP.
  16. Turn ignition off. Disconnect harness connector from tank pressure control solenoid. Using an ohmmeter, measure resistance of solenoid. If resistance is 28-36 ohms at 68°F (20°C), go to next step. If resistance is not as specified, replace tank pressure control solenoid. Retest system.
  17. Blow into port "A". Air should flow through filter and not port "B". Using fused jumper wires, connect a 12-volt battery to solenoid terminals. Blow into port "A". Air should flow through port "B" and not through filter. If operation is as specified, check tank pressure control solenoid harness for open or short. Repair as necessary. Retest system.
  18. Disconnect vacuum hoses from EVAP canister. Blow air into bottom port of EVAP canister. Air should flow through both top ports with no restriction. If operation is as specified, go to next step. If operation is not as specified, replace EVAP canister. Retest system.
  19. Turn ignition off. Disconnect purge hose from intake manifold. Disconnect tank pressure control valve hose from solenoid vacuum valve. Using a fused jumper wire, connect (backprobe) PCM harness connector "B", terminal No. 25 (Light Green/Yellow wire) to ground and go to next step.
  20. Turn ignition on. Plug air valve hose end. Using a hand-held vacuum pump, apply vacuum to pressure control valve hose end. Apply 0.5 psi (.04 kg/cm2 ) to purge hose and seal. Ensure pressure holds at more than 0.47 psi (.03 kg/cm2 ) for at least 15 seconds. If pressure holds as specified, go to next step. If pressure does not hold as specified, locate leak using soapy water. Repair as necessary. Retest system.
  21. Check tank pressure sensor and fuel level sensor following procedures in DTCs P0450 and P0461. Repair as necessary. If no problems are found, replace PCM. Retest system.
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