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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics - 4.3L >> Diagnostic Tests >> DTC P0496: Evaporative Emission System High Purge Flow >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Start engine. Seal the EVAP system using the Purge/Seal function with a scan tool. Increase the engine idle to 1200-1500 RPM. Observe the fuel tank pressure sensor in. H2O with a scan tool. Is the fuel tank pressure sensor parameter within -1 to 1 H2O? If yes, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. If no, go to next step.
  3. Turn ignition off. Disconnect the EVAP purge pipe from the EVAP purge solenoid. Turn ignition on, with engine off. Observe the fuel tank pressure sensor with a scan tool. Is the fuel tank pressure sensor parameter within -1 to 1 H2O? If yes, go to next step. If no, go to step  5.
  4. Replace EVAP purge solenoid. After replacing solenoid, go to step  6.
  5. Replace Fuel Tank Pressure (FTP) sensor. After replacing sensor, go to next step.
  6. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  7. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? Go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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