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Home >> Saab >> 1999 >> 9-3 Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - TRIONIC T5 Fuel Control System >> Diagnostic Tests >> DTC P0455: EVAP System Large Leak Detected
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DTC P0455: EVAP System Large Leak Detected

  1. Check to make sure fuel filler cap is tight. Inspect fuel filler cap seal and sealing surface. Inspect fuel tank, filler pipe and vent pipe for leaks. If any problems are found, repair as necessary. Go to step  4 . If no problems are found, go to next step.
  2. Connect vacuum/pressure pump to EVAP purge valve hose port opposite of electrical connector. Test purge valve operation by ensuring that valve is closed (holds vacuum) when no current is applied, and is open when current is applied (does not hold vacuum). If operation is as specified, go to next step. If operation is not as specified, replace EVAP canister purge valve and go to step  4 .
  3. Locate EVAP shut-off valve under vehicle, attached to fuel filler pipe. Disconnect EVAP shut-off valve electrical connector. Energize EVAP shut-off valve by applying battery voltage to connector terminal No. 1 (Green/Red wire) and ground to connector terminal No. 2 (Green wire). Disconnect vacuum hose at EVAP canister purge valve going to EVAP canister. Connect vacuum/pressure pump to hose. Remove fuel filler cap and plug hole for roll-over valve. Use vacuum/pressure pump to apply 3 in. Hg of vacuum to EVAP canister. There should be no visible change in vacuum reading for at least 10 seconds. If operation is as specified, replace fuel filler cap. If operation is not as specified, there is a leak in either the EVAP canister, EVAP shut-off valve or hoses between them. Repair as necessary. Go to next step.
  4. Connect TECH 2 scan tool to DLC. Turn ignition on. Contact TRIONIC 5 OBD II. Select ACTIVATE: EVAP DIAGNOSIS. Wait until status indicates READY and check results of test. If a leak is still indicated, problem is still present.
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