Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
  • Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
  • Refer to the J 41413-200  operation manual for detailed instructions in Evaporative Emission System Diagnosis . See Special Tools .
  1. Connect the J 41413-200  to the vehicle EVAP service port. See Special Tools . For vehicles without a service port, disconnect the purge tube at the quick connector on the EVAP canister side of the purge solenoid valve and install the CH-48096  .
  2. Use a scan tool to seal the EVAP system.
  3. Use the flow meter on the J 41413-200  , calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
    • If a leak is detected, use the J 41413-200  to apply smoke to the EVAP system at the service port or the purge tube until the leak is located using the J 41413-SPT  . See Special Tools .
  4. To test for a restriction in the purge path, connect the J 41413-200  nitrogen/smoke hose to the J 41413-311  brass cone adapter. Disconnect the hose at the fuel cap end of the GE-41415-50  . See Special Tools . Connect the J 41413-311  to the disconnected hose on the GE-41415-50  . See Special Tools . Install the GE-41415-50  filler neck end only to the vehicle.
  5. Allow the engine to idle.
  6. Use the Purge/Seal function to seal the system with a scan tool.
  7. Command the EVAP canister purge solenoid valve to 30 percent.
  8. The vacuum/pressure gage on the J 41413-200  and the FTP parameter on the scan tool should both show vacuum. See Special Tools .
    • If the vacuum/pressure gage shows vacuum, but the FTP parameter does not show vacuum, replace the FTP sensor.
    • If neither the FTP parameter nor the vacuum/pressure gage shows vacuum, repair the restriction in the purge path.
  9. Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 volts, and the values are similar between the scan tool and the vacuum/pressure gage on the J 41413-200  . See Special Tools .
    • If the values are not similar, or the voltage did not reach 3.2 volts, replace the FTP sensor.
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When to See a Mechanic

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

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