Join Now
International Automotive Technicians Network

P0421 Diagnostic Trouble Code Discussion for October 2013

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
2003 Volkswagen Passat GL 2.8L Misfire cyl #3 VIN: WVWTH63B63
P0421: Cat converter efficiency b1. THIS 2.8L V6 HAD A CONSISTENT MISFIRE AT IDLE ON CYL#3. THE MISFIRE COUNTER JUST KEPT COUNTING UP ON THE VAG-COM AS THE ENGINE SAT IN THE SHOP BAY RUNNING AT IDLE. WE SWAPPED THE SPARK PLUGS, FUEL INJECTORS, CHECKED THE COMPRESSION AND THE FUEL PRESSURE, SMOKE...
October 08, 2013
2003 Volkswagen Passat GL 2.8L Misfire cyl #3 VIN: WVWTH63B63
P0421: Cat converter efficiency b1. THIS 2.8L V6 HAD A CONSISTENT MISFIRE AT IDLE ON CYL#3. THE MISFIRE COUNTER JUST KEPT COUNTING UP ON THE VAG-COM AS THE ENGINE SAT IN THE SHOP BAY RUNNING AT IDLE. WE SWAPPED THE SPARK PLUGS, FUEL INJECTORS, CHECKED THE COMPRESSION AND THE FUEL PRESSURE, SMOKE...
October 08, 2013