Hi All,

I appreciate all the good advice I have gotten from this forum. I have another issue with my car. My Check Engine Light came on and it is Code PO420. That is telling me my catalytic convertor needs to be replaced. I am wondering can I replace this myself or would it be best to take it into the shop for this kind of repair. I have called the local muffler shops and they want about 400 Dollars installed. I can buy the part from the local parts store for 159.00. But I looked under the car and the bolts look all rusted. What does everyone recommend? Any advice would be appreciated. Thanks.

1996 Accord 2.2L 2 Door Coupe
200,500 miles

 

How is the rest of the exhaust system (behind the cat)? If it's original and your car has 200,000 miles on it, it wouldn't hurt to replace it at the same time. And if you are replacing the entire system at the same time, the job isn't that hard - just the one connection from the downpipe to the cat that you have to worry about.

I've not replaced any of the exhaust parts on my Honda but have swapped out systems on other cars that I've had. Swapping out a single piece like the cat is very tedious.

 

I've replaced some stuff on my Civic, I just had to make sure to spray lot's of WD-40 on the bolts and let it sit a little while before I could loosen anything. It looks like you should be able to unbolt the cat on both ends and pull it out. You'll want to replace the gaskets too.



You should check the rest of the exaust, cause it might be something else, like a rusted out pipe that is contributing to the problem.

With that said, I don't know how strict shops are when you get your emissions done, but the cat is regulated by the EPA and there are certain rules you have to follow, mostly you have to buy one that is certified by the EPA, and for companies to sell them, they need to be certified by the EPA, so you should be safe, but it's probably a good idea to check. If you want some good reading here are the links.

Installing http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf
Rules http://www.epa.gov/oms/consumer/warr95fs.txt

 

Wow! Great diagram. This is for the 1996 Accord Coupe. I appreciate all the assistance and great information. Thanks all.

 

do not take it too a shop. they are ripping you off. 400 bucks to install a direct fit cat? that's outrageous! do it yourself. if wd40 don't work, use pb penertrating oil. works everytime for me. use a 6 point socket and not a 12. use a rachet that will give you enough levrage/torque.

 

yupp i wudnt pay 400 for installation...kinda overpriced lol but yea shudnt be too hard, make sure u used air tools or at least a impact wrench.

 

FYI, code P0420 doesnt always mean change the cat. Its catalyst low efficiency detected. There is no sensor inside the car to detect this, it is determined by the primary and secondary O2 sensors. I would have those checked out on a oscilloscope and make sure that they are working properly before you go change the car.

The primary o2 sensor should be switching from peak to peak to find the best AFR, where as the secondary o2(behind the cat) is measuring how much unburnt fuel is coming out after the cat. If that sensor is dead, the computer will read that the catalytic isnt doing anything, and throw a code P0420.

I have read many TSB's on this exact code, and more often then not, I find bad o2 sensors over the cat.