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Home >> Buick >> 2007 >> Allure CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 68 (Engine Control System & Fuel System - 3.6L - DTC P0335 To DTC P2097) >> DTC P0420 >> Circuit/System Testing

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. Observe the scan tool DTC information. Verify there are no HO2S, or misfire DTCs set.
  2. Inspect and verify the following:
    • The catalytic converter is an original part
    • The HO2S 2 is secure and the wiring is not damaged, or contacting the exhaust
    • The exhaust system for leaks, damage, or missing hardware
    • If a condition is found, repair as necessary.
  3. IMPORTANT: Before replacing the catalytic converter, correct any conditions that may have damaged the converter.
  4. If a condition is not located, replace the catalytic converter.