Circuit Description

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Circuit Description
WARNING: This page is about a different car, the 2002 GMC Sonoma and 2002 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.

A restricted or blocked Evaporative Emission (EVAP) vent path is detected by PCM commanding the purge valve on (open) and vent valve on (closed), allowing a vacuum to be applied to EVAP system. Once a calibrated vacuum level has been reached, PCM commands purge valve off (closed) and vent valve off (open) while monitoring the Fuel Tank Pressure (FTP) sensor for a decrease in vacuum. If vacuum does not decrease to near zero inches H2O in a calibrated time, DTC will set.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.