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Home >> Jeep >> 2024 >> Grand Cherokee Summit >> Repair and Diagnosis >> External Pages >> Different car >> Section 25 (5.7L - DTCS P0420 To P0461) >> DTC Troubleshooting >> P0420-Catalyst System Efficiency Below Threshold Bank 1 >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2024 Jeep Grand Cherokee L. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL CONDITION
AGING OR FOULED UPSTREAM O2 SENSOR
CATALYTIC CONVERTER

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE  .