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Home >> Chrysler >> 2009 >> 300 Signature Series >> Repair and Diagnosis >> External Pages >> Different car >> Section 51 (Engine Controls - DTCS P0330 To P0480) >> Diagnosis And Testing >> P0420-Catalyst 1/1 Efficiency >> Theory Of Operation >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes 
EXHAUST LEAK
ENGINE MECHANICAL CONDITION
AGING O2 SENSOR
CATALYTIC CONVERTER

Always perform the  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE  before proceeding. 

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