Join Now
International Automotive Technicians Network

P0421 Diagnostic Trouble Code Discussion for April 2005

Warmup Catalyst Efficiency Low (Bank 1)


Note: This is a professional automotive technician's resource.
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Trouble Ticket Help Requests for DTC P0421
Help Request Posted
1998 Hyundai Accent L 1.5L MIL Lamp on VIN: KMHVD14NXW
P0421: Warmup Catalyst Efficiency Below Normal (Bank 1). hyundais test is very short--replace converter and/or PCM---not ready to replace pcm yet--any suggestions???
April 05, 2005
1998 Hyundai Accent L 1.5L MIL Lamp on VIN: KMHVD14NXW
P0421: Warmup Catalyst Efficiency Below Normal (Bank 1). hyundais test is very short--replace converter and/or PCM---not ready to replace pcm yet--any suggestions???
April 05, 2005