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Home >> Buick >> 2002 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P1441: EVAP System Flow During Non-Purge >> 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. Are DTCs P0443, P0449, P0452 or P0453 also set? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Remove the fuel fill cap. Turn ignition on, with engine off. Monitor the Fuel Tank Pressure (FTP) sensor with a scan tool. Does the scan tool indicate fuel tank pressure within -0.5 to 0.5 in. H2O? If yes, go to next step. If no, go to DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE .
  4. Disconnect the Evaporative Emission (EVAP) purge pipe from the EVAP canister purge valve. Install a hand held vacuum gauge to the EVAP purge port. Disconnect the EVAP canister purge valve harness connector. Monitor vacuum on the vacuum gauge. Start and allow engine to idle. Increase engine speed to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  5. Replace the EVAP canister purge valve. After repairs, go to next step.
  6. With a scan tool, capture and record the Fail Record data and clear the DTCs. Perform the Service Bay Test. Does the scan tool indicate that the Service Bay Test passed? If yes, go to next step. If no, go to step  3.
  7. Using scan tool, observe stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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