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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 28 (Engine Control System - Self-Diagnostics) >> Diagnostic Tests >> DTC P0420: Catalyst System Low Efficiency >> Conditions For Running DTC
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Conditions For Running DTC

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
  1. Engine coolant temperature is more than 158°F (70°C).
  2. Engine speed is 2500-3000 RPM for at least 3 minutes while driving at certain vehicle speeds.
  3. Engine is operating in Closed Loop.