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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 2.0L >> Diagnostic Tests >> DTC P0446: EVAP Vent System Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Observe the Fuel Tank Pressure Sensor parameter on the scan tool. Remove the fuel filler cap. Is the fuel tank pressure within 0.0-0.5 in. H2O (0.0-0.9 mm Hg) with the fuel filler cap removed? If yes, go to next step. If no, go to DTC P0451: FUEL TANK PRESSURE SENSOR PERFORMANCE .
  3. Turn ignition off. Disconnect the electrical connector from the EVAP canister vent valve. Measure the resistance of the EVAP canister vent valve using a DVOM. Is the resistance within the specified range of 28-36 ohms at 68°F (20°C)? If yes, go to next step. If no, go to step  11.
  4. Turn ignition on, with engine off. Probe the ignition positive voltage circuit at the vent valve electrical connector with a test light connected to ground. Does the test light illuminate? If yes, go to next step. If no, go to step  7.
  5. Connect the electrical connector to the EVAP canister vent valve. Clear DTCs with a scan tool. Backprobe vent valve control circuit with a test light connected to battery voltage. Command the vent valve ON and OFF with scan tool. Does test light illuminate only when commanded ON with scan tool? If yes, go to step  8. If no, go to next step.
  6. Check for an open or a short in the vent valve control circuit. Repair as necessary. Was a repair necessary? If yes, go to step  13. If no, go to step  12.
  7. Check for an open in the ignition positive voltage circuit. Repair as necessary. After repairs, go to step  13.
  8. Check the EVAP vent valve inlet air filter and line for blockage. Was a repair necessary? If yes, go to step  13. If no, go to next step.
  9. Check the EVAP canister for restrictions or blockages. Did the canister pass all tests? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  10. Replace EVAP canister. After repairs, go to step  13.
  11. Replace EVAP canister vent valve. After repairs, go to step  13.
  12. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  13. Turn ignition off. Remove DOME fuse (located in passenger compartment fuse block). Reinstall DOME fuse. Reset radio clock time. Start engine. Operate the vehicle within the Conditions for Running the DTC or until the DTC P0446 diagnostic test has run. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  14. Using scan tool, observe stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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