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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 11 (Engine Controls And Fuel - 6.0L (L96) - DTC P0351 To DTC P2636 And Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> DTC P0420 Or P0430: Catalyst System Low Efficiency >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify the conditions listed below do not exist with the appropriate catalytic converter:
    • Dents
    • Severe discoloration caused by excessive temperatures.
    • Road damage.
    • Internal rattles caused by damaged catalyst substrate.
    • Restrictions
      • If a condition is found 

        Replace the catalytic converter.

      • Go to next step: If no condition is found 
  2. Verify the conditions listed below do not exist with the exhaust system:
    • Leaks.
    • Physical damage.
    • Loose or missing hardware.
      • If a condition is found 

        Repair or replace the component as necessary.

      • Go to next step: If no condition is found 
  3. Verify the conditions listed below do not exist with the appropriate B52B Heated Oxygen Sensor 2:
    • Incorrect torque.
    • Damage.
      • If a condition is found 

        Replace the B52B Heated Oxygen Sensor 2 or repair the condition as necessary.

      • Go to next step: If no condition is found 
  4. Replace the catalytic converter.