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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify the following conditions are not present:
    • Incorrect EGR valve for engine application
    • A vacuum leak between the EGR valve and the intake manifold
    • Signs of external leakage usually indicated by carbon buildup around the mating surfaces of the components or an audible exhaust noise
    • Restrictions in the passages or EGR valve caused by carbon deposits or casting flash
    • MAP sensor for being shifted, stuck, skewed, and for correct vacuum supply-Refer to DTC P0106 .
      • IMPORTANT: Restrictions can cause excessive back pressure and low engine vacuum.
    • Leaking, restricted, or modified exhaust system
    • Mechanical failure in the engine such as worn piston rings, camshaft, or incorrect timing components installation-Refer to Symptoms - Engine Mechanical .
  2. If all conditions test normal, replace the EGR valve.
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