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P0172 (2) Chevrolet Uplander I

Testing & Diagnostics ~213 words
  1. Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The value should be more than -25 percent with the engine running at operating temperature.
  2. If the value is not more than -25 percent, inspect for the following: With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 19-42 kPa. If the MAP sensor parameter is not between 19-42 kPa, refer to «DTC P0106, P0107 or P0108»(ref-241735-S14863720202006081100000) .
  3. Vacuum hoses for splits, kinks and proper connections
  4. The inlet screen of the MAF sensor for blockage
  5. A malfunctioning MAF-Refer to «DTC P0068 or P0121»(ref-241735-S07537812612006081100000) or «DTC P0101 or P1101»(ref-241735-S35341406412006081100000) .
  6. The air duct for being collapsed or restricted
  7. The air filter for being dirty or restricted
  8. Objects blocking the throttle body
  9. Excessive fuel in the crankcase
  10. A saturated evaporative canister, a stuck purge valve or the fuel cap not sealing
  11. The evaporative emissions control system for proper operation
  12. Excessive fuel pressure
  13. Properly functioning fuel injectors
  14. Fuel contamination
  15. The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system
  16. The HO2S signal circuit shorted to voltage

More articles — Engine Controls - 3.9L - DTC P0011 to P0420