Replacing Oxygen Sensor.

OK. Autozone checked and found the codes: 0401 and 0420, which the
0401 is the PRG and 0420 is the catalytic converter, but when they
checked the ECU a month ago, the only code was for the O2 sensor. Now
after replacing the O2 sensor, the check engine light doesn't come on
until I drive the car for 50 miles, which I'm guessing is how long it
takes to complete the tests that are returning the codes above.

I would be convinced that I have to replace my catalytic converter,
but I've already replaced it about 1-year ago, and it was an OEM, and
not a generic catalytic converter.

Need to pass emissions soon.

Thanks,

--TJ

 

i suggest you reset the codes and give this car an "italian tune-up".
that may clean up the catalyst sufficiently to have it process the
exhaust correctly. if that doesn't work, consider replacing the second
sensor, the one that is downstream of the cat.

egr problems are common and a huge pita, so you need to deal with that
as a separate issue. google this group for solution. in the future, i
will help you to stick only to good quality branded gasoline, not
discount stuff.

 

Ended up having the replace the catalyst converter and post cat o2
sensor. The shop I took it to charged me $343 that included parts,
labor, and tax. They ended up having to do a little welding, so if
the check engine light stays off, I will consider this a success.

At that price, should I use this shop in the future?

Thanks,

--TJ

 

A catalytic converter all by itself runs about $400 at
online OEM Honda parts sites. Add another $100 for an OEM O2
sensor.

They did it so cheaply I bet they used non-OEM all the way
around. Dunno if that's okay for the cat converter. Around
here, many of us feel only OEM is the way to go with the O2
sensor.

The underlying cause of the failed converter needs to be
considered.

 

F23A1 or F23A4 engine? Calif emissions? Probably not given the $343
price tag.

But the catalytic converter is usually the victim and not the villain.
So make sure the engine is properly tuned up. When was the last time
you had the valve clearances checked? Might want to do that on your
next "tune up". If the clearances are tight, especially on the
exhausts, swap out with NGK Iridium plugs and, on a non-calif vehcile,
a new Bosch planar type sensor (#15730, F23A1, $65.79 rockauto.com)
for the upstream. Planars are more resistant to contamination as
well.

I know many like OEM sensors. If they are NTK/NGK fine, but I don't
really care for Densos. Even their plugs are cheap compared to NGKs.
Glad I didn't recommend a converter replacement for a V6 owner. Two
Bosch planars solved it for me, and the Denso junk didn't even set a
code.

 

On to replacing the EGR valve, which hopefully will get my car to pass
emissions.

--JP

 

Replaced EGR valve, and now I'm still getting P401. The shop said to
bring it in to clean out the system for less than $100. I guess they
have to clean out the pipe before the EGR valve, which is something I
can do they said, but it's very time consuming.

Any advice?

Thanks,

--TJ

 

Finally passed WA Emissions. My 98 Honda Accord has 215K rough miles
that includes trips to TX and CA and several months in Dallas. Also,
I drive daily in heavy traffic.

Problem: Check engine light. Codes reported: P401 and P420

Solution: Replaced O2 Sensor (POST CAT), Replaced Catalyst converter,
Replaced EGR Valve, and cleaned EGR passage.

Cost: Catalyst Converter $150, O2 Sensor $50, EGR Valve $125, and
Service $250. Oh yeah, I received two traffic violation tickets which
were for $216/ea, but I'm going to take the second ticket to
mitigation.

Thanks to this group for their experience and help.

--TJ

 

snip<<

Congratulations on a long battle won. I just finished a 6 month battle with
a recalcitrant 98 Civic HX MT that threw P401 and P1491 codes continually
at the end. Finally resolved the issue(s) with a new EGR valve and cleaning
passageways. I did it myself and wrote it up with pics that should be on the
web shortly. Look for the announcement any day now.
--
Pickleman

Please remove "yourpants" to reply
1988 Civic DX retired with 234K due to extensive rust and gas tank problems
1998 Civic HX MT with 138K
2000 CRV EX MT with 98K