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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1998 (Engine Controls And Fuel - 3.6L (LCS) - DTC P0638 To DTC P2229) >> DTC P2177, P2179, P2187, or P2189 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, open the hood to disable the Auto-Stop function.
  2. Ignition ON, verify the scan tool hood position parameter displays Open.
    • If the hood position does not display Open, refer to DTC P254F .
  3. Observe the DTC information with a scan tool. DTC P2177, P2179, P2187, or P2189 should not be set.
  4. Ignition ON, observe the barometric pressure (BARO) sensor pressure parameter and compare the reading on the scan tool to the barometric pressure table. Refer to Altitude Versus Barometric Pressure .
  5. Engine at normal operating temperature, observe the Total Fuel Trim Avg. parameter with a scan tool. The Total Fuel Trim Avg. should be between -22 to +21 percent.
    • If not within the specified range, verify none of the following conditions exist:
      • The air intake system after the MAF sensor for vacuum leaks
      • Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) .
      • Splits, kinks, or improper connections at the vacuum hoses-Refer to Emission Hose Routing Diagram .
      • The fuel system is operating lean. Refer to Fuel System Diagnosis .
      • Vacuum leaks at the intake manifold or throttle body
      • Leaking crankcase ventilation system
      • The engine control module grounds for being clean, tight, and in the correct locations
      • A high engine oil level condition-A high engine oil level causes oil residue to form on the mass air flow (MAF) sensor, causing a lean indication. The MAF sensor does not need to be replaced.
      • Vacuum leaks that only affect one bank of the engine-For example, the intake manifold, the injector O-rings.
      • Lean injectors-Refer to DTC P029D, P02A1, P02A5, P02A9, P02AD, or P02B1 .
      • Missing, restricted, or leaking exhaust components-Refer to Symptoms - Engine Exhaust .
      • The heated oxygen sensor (HO2S) is installed securely and the electrical connector is not contacting the exhaust system.
      • A mass air flow (MAF) sensor signal that is skewed-If the Short Term FT parameters for both banks changes greater than 20 percent when the MAF sensor is disconnected, refer to DTC P0101 .
      • An engine mechanical condition-Refer to Symptoms - Engine Mechanical .
  6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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