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Home >> Mitsubishi >> 2003 >> Lancer Evolution >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0456: EVAP Control System Very Small Leak Detected >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE parameter. If scan tool displays 1.51 volts, go to next step. If scan tool display is not as specified, go to DTC P0452: FUEL TANK PRESSURE SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE 
  3. Ensure EVAP canister vent hose is not damaged or disconnected. Check EVAP canister and fuel cap for damage. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, install fuel cap and go to next step.
  4. Turn ignition on. Using scan tool, read and record scan tool FAIL RECORDS data. Operate vehicle within FAIL RECORDS conditions as recorded. Monitor DTC information for DTC P0456. If scan tool indicates P0456 FAILED THIS IGNITION, go to next step. If scan tool does not display as specified, check for intermittent problem. See DIAGNOSTIC AIDS .
  5. Start engine. On scan tool, observe FUEL TANK PRESSURE parameter. If parameter is 1.02-1.86 volts, check for intermittent problem. See DIAGNOSTIC AIDS . If parameter is not as specified, go to next step.
  6. Start engine and allow to idle. Using scan tool, command EVAP canister vent valve ON (closed). Observe EVAP CANISTER VENT VALVE SECOND VALUE. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  7. Check for disconnected or leaking fuel tank vapor line. Disconnected or damaged EVAP purge line. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, check for intermittent problems. See DIAGNOSTIC AIDS .
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