Question about Mazda MPV
P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)
A code P0421 may mean that one or more of the following has happened:
Measure the voltage at the oxygen sensor on Bank 1 (the rear sensor, or the sensor after the converter). In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.
One thing to note is that many vehicle manufacturers
offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.
Posted on Apr 14, 2009
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Posted on Jan 02, 2017
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