P0420 Code Question
#1
07-22-2018, 09:37 PM
P0420 Code Question
A couple of weeks ago the MIL lit up. When I checked the code it was a P0133 (O2 sensor, Bank 1). I replaced the O2 sensor, but now I have an intermittent P0420 code. Does anyone know if the two are related and if there is something causing it other than the worst possible located Bank 1 catalytic converter?
#2
07-22-2018, 10:20 PM
#4
07-23-2018, 08:23 AM
#5
08-10-2018, 10:57 AM
#6
08-10-2018, 12:48 PM
#7
08-10-2018, 02:39 PM
Veteran Member
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#10
08-13-2018, 05:32 PM
Veteran Member
are you sure the o2 sensor is bad did you test it
In your case, the P0420 code stands for “Catalyst System Efficiency Below Threshold (Bank 1).” When you receive a P0420 code it means your catalytic converter is not operating at maximum efficiency. Usually this means your catalytic converter needs to be replaced or there is a problem with your O2 (oxygen) sensors.
In your case, the P0420 code stands for “Catalyst System Efficiency Below Threshold (Bank 1).” When you receive a P0420 code it means your catalytic converter is not operating at maximum efficiency. Usually this means your catalytic converter needs to be replaced or there is a problem with your O2 (oxygen) sensors.
#11
08-13-2018, 07:35 PM
Senior Member
#12
08-14-2018, 06:53 AM
#13
08-19-2018, 06:39 PM
Latest Update: MIL went off then on again, so I checked the codes again. This time I had a P0305 and P1316 in addition to the P0420. So here is what I think is happening:
1. I have a misfire on #5 that has been happening, but finally threw a code.
2. P0305 code caused the car to throw a P1316 code.
3. The intermittent #5 misfire caused the O2 upstream sensor to fail (changed last month) and then the cat to become contaminated to the point is not working well. Which caused the P0420 code.
Does that sound reasonable?
Since I bought the car I have smelled burning oil when it is stopped at a traffic light or at idle. I’m thinking I have a valve (cam) cover gasket failure that fouled the #5 plug at the heart of all this. Hopefully the cat is not too far gone that it can’t be saved.
Today I ordered new valve cover gaskets, coils, plugs, upper and lower intake gaskets. I won’t have time to do the work for a couple of weeks. Interested in what y’all think about my theory.
1. I have a misfire on #5 that has been happening, but finally threw a code.
2. P0305 code caused the car to throw a P1316 code.
3. The intermittent #5 misfire caused the O2 upstream sensor to fail (changed last month) and then the cat to become contaminated to the point is not working well. Which caused the P0420 code.
Does that sound reasonable?
Since I bought the car I have smelled burning oil when it is stopped at a traffic light or at idle. I’m thinking I have a valve (cam) cover gasket failure that fouled the #5 plug at the heart of all this. Hopefully the cat is not too far gone that it can’t be saved.
Today I ordered new valve cover gaskets, coils, plugs, upper and lower intake gaskets. I won’t have time to do the work for a couple of weeks. Interested in what y’all think about my theory.
#18
08-21-2018, 10:36 AM
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Location: Damon /Houston, Texas
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Latest Update: MIL went off then on again, so I checked the codes again. This time I had a P0305 and P1316 in addition to the P0420. So here is what I think is happening:
1. I have a misfire on #5 that has been happening, but finally threw a code.
2. P0305 code caused the car to throw a P1316 code.
3. The intermittent #5 misfire caused the O2 upstream sensor to fail (changed last month) and then the cat to become contaminated to the point is not working well. Which caused the P0420 code.
Does that sound reasonable?
Since I bought the car I have smelled burning oil when it is stopped at a traffic light or at idle. I’m thinking I have a valve (cam) cover gasket failure that fouled the #5 plug at the heart of all this. Hopefully the cat is not too far gone that it can’t be saved.
Today I ordered new valve cover gaskets, coils, plugs, upper and lower intake gaskets. I won’t have time to do the work for a couple of weeks. Interested in what y’all think about my theory.
1. I have a misfire on #5 that has been happening, but finally threw a code.
2. P0305 code caused the car to throw a P1316 code.
3. The intermittent #5 misfire caused the O2 upstream sensor to fail (changed last month) and then the cat to become contaminated to the point is not working well. Which caused the P0420 code.
Does that sound reasonable?
Since I bought the car I have smelled burning oil when it is stopped at a traffic light or at idle. I’m thinking I have a valve (cam) cover gasket failure that fouled the #5 plug at the heart of all this. Hopefully the cat is not too far gone that it can’t be saved.
Today I ordered new valve cover gaskets, coils, plugs, upper and lower intake gaskets. I won’t have time to do the work for a couple of weeks. Interested in what y’all think about my theory.