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P0421 Diagnostic Trouble Code Discussion for June 2005

Warmup Catalyst Efficiency Low (Bank 1)


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Trouble Ticket Help Requests for DTC P0421
Help Request Posted
2000 Volkswagen Passat 4 Motion 2.8L MIL Lamp on VIN: WVWUH23B5Y
P0421: cat bank 1 efficiency. In for check engine light and inspection. codes for cat efficiency both banks set, smoke checked for vacum leaks, ok. Checked maf meter reading, well within spec., checked front o2 sensors switching fast, cleared codes. Light came back on 2 days both cat eff. ...
June 24, 2005
2000 Volkswagen Passat 4 Motion 2.8L MIL Lamp on VIN: WVWUH23B5Y
P0421: cat bank 1 efficiency. In for check engine light and inspection. codes for cat efficiency both banks set, smoke checked for vacum leaks, ok. Checked maf meter reading, well within spec., checked front o2 sensors switching fast, cleared codes. Light came back on 2 days both cat eff. ...
June 24, 2005