Join Now
International Automotive Technicians Network

P0421 Diagnostic Trouble Code Discussion for April 2007

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
2000 Saturn LS2 3.0L MIL Lamp on VIN: 1G8JW52R6Y
P0421: warm up catalyst below threshold. this customer called me and asked for a tow into the shop from a nearby town because the car stalled and then would crank and not start but she wound up being able to start car after waiting one half hour.car started up for us but on road test it would stall a...
April 20, 2007
2000 Saturn LS2 3.0L MIL Lamp on VIN: 1G8JW52R6Y
P0421: warm up catalyst below threshold. this customer called me and asked for a tow into the shop from a nearby town because the car stalled and then would crank and not start but she wound up being able to start car after waiting one half hour.car started up for us but on road test it would stall a...
April 20, 2007