P0421 Diagnostic Trouble Code Discussion for November 2008
Warmup Catalyst Efficiency Low (Bank 1)
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| Help Request | Posted | |
| 2003 Mazda Protege ES 2.0L Misfire, MIL Lamp on VIN: JM1BJ22583 P0421: Warmup Catalyst Efficiency Below Normal (Bank 1). had po3oob code , replaced plugs and filters then it has come back with multiple missfire code and cat. efficency below thresshold .../. what does this mean . is it related to the front or rear o2 sensor , and the multiple missfire code ?? any help appreciated |
November 04, 2008 | |
| 2003 Mazda MPV LS 3.0L MIL Lamp on, P0421 VIN: JM3LW28A53 P0421: Warmup Catalyst Efficiency Below Normal (Bank 1). P0421 sets just after other shop performed above work!!..perhaps ect??no code for it eng temp ok..data stream o.k. |
November 22, 2008 |
