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Hi. I have a 2006 Mazda 2 with about 168k km on it. I will only be keeping it till it reaches 10 years old as local regulations only allows that.
I recently got a P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1) . Some say the pre cat o2 sensor is bad and others say the cat is bad. Some workshops are quoting me high prices stating the bank 1 has dual function. some say it is not so easy for a cat to go bad.
Can someone help me. I’m not sure if my car has has a pre cat o2 sensor going to the obd. If it has, it should just show the error code for that bad sensor right? The available adapter that has the o2 word captured on my obd2 reader are these.
Bank 1, Sensor 2: Oxygen sensor & short fuel term fuel trim.
O2 S1 Equiv. Ratio and /or current.From these adapters, will it show that the o2 sensor is bad? Or is it really a dead cat? Help greatly appreciated.
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Am I able to monitor the performance of the oxygen sensor and cat using obd doctor app? I am able to look at live data but what am I suppose to look at?
[quote=”yanbros” post=116939]Am I able to monitor the performance of the oxygen sensor and cat using obd doctor app? I am able to look at live data but what am I suppose to look at?[/quote]
The link I sent explains what you should see. The rear o2 voltage
should sit at a constant voltage.I was able to monitor the o2 sensor voltage for bank 1 sensor 2 which I think is the rear one and the voltage was flaucuating. I could not find bank 1 sensor 1 voltage. I also monitored the air fuel ratio which was quite stable near 14.8. Would this be a bad cat or front o2 sensor?
[quote=”yanbros” post=117153]I was able to monitor the o2 sensor voltage for bank 1 sensor 2 which I think is the rear one and the voltage was flaucuating. I could not find bank 1 sensor 1 voltage. I also monitored the air fuel ratio which was quite stable near 14.8. Would this be a bad cat or front o2 sensor?[/quote]
If both voltages are fluctuating the same then the cat is bad.
here is another test you could do.http://www.ericthecarguy.com/fuel-and-emissions/539-p0420-how-to-diagnose-a-bad-catalytic-converter
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