Honda

Have Honda Questions? Ask a Honda Repair Expert.

Ask an Expert,
Get an Answer ASAP!

Honda

99 Honda Civic lx, p0420 after aftermarket distributor

Customer Question
replacement. Car runs fine...
99 Honda Civic lx, p0420 after aftermarket distributor replacement. Car runs fine but p0420 won't clear. Need troubleshooting path. Cannot afford dealer
Submitted: 1 year ago.Category: Honda
Show More
Show Less
Ask Your Own Honda Question
Answered in 11 minutes by:
12/27/2015
Mechanic for Honda: camerontech, Auto Service Technician replied 1 year ago
camerontech
camerontech, Auto Service Technician
Category: Honda
Satisfied Customers: 576
Experience: diagnostic auto tech
Verified

hi there,

im cam a licenced diagnostic tech.

the p0420 is a catylist efficiency code.

I have seen this code many times on these engines and it has usually been the cat conveter.

a cracked exhaust manifold will also cause this code.

to check the cat...

montor the front and rear o2 sensors. if the rear o2 sensor is matching the front o2 sensor than the cat will need to be replaced

the front o2 should be toggling between .3 volts to .75 volts fairly quickly, while the rear o2 should be a steady slow wave volt range.

if the rear is toggling fast, that it finished.

this can be seen properly with a graphing scale on a diagnostic scanner.

you can use a multi meter volt scale but it will be a little slower to monitor as multimeters do not have a fast enough processor to catch every crosscount.

for me. it has always been a defective cat.

thanks and i appreciate positive ratings

cam

Ask Your Own Honda Question
Customer reply replied 1 year ago
I was thinking it was going to be the cat, I am going to look at those 02 sensors but I was already planning on maybe having to replace the cat.My next question/concern is if I do get a new cat and I haven't fixed the old problem i.e. defective igniter terminals on that new distributor that need crimping, will that burn up my new cat?Also was wondering if you have any experience with aftermarket cats in California and if the approved aftermarket cats are a reliable option?Thank You
Mechanic for Honda: camerontech, Auto Service Technician replied 1 year ago

hi there.

sorry for the late reply... last of the xmas dinners.

regarding your new cat..

for the aftermarket cat, as long as its an "obd2" cat, and a good quality the cali emmission will be no problem. Its the bargain cats that will be a waste of money. spend extra as the obd2 cats will have larger elements inside and better chemical reaction qualities.

if you still have a misfire, this will lead to premature cat failure. If the engine light is flashing, this is a warning that immidiate cat damage is happening. the vehicle computer has pretty decent on board monitors that pick up problems.

if you have a decent scanner with misfire counter data screens and fuel trim data, you will be able to determine if you will have cat damaging issues or not.

if you need any more assistance id be happy to help!

please dont forget to rate me!

thanks

cam

Ask Your Own Honda Question
Mechanic for Honda: camerontech, Auto Service Technician replied 1 year ago

hi there,

just a reminder to please rate me as this important for my page

thanks

cam

Ask Your Own Honda Question
Mechanic for Honda: camerontech, Auto Service Technician replied 1 year ago

c

Ask Your Own Honda Question
Customer reply replied 1 year ago
Cameron,So sorry for the delayed response as I've run into some trouble with my car. I decided to try and crimp the ingniter terminals on my distributor to rule out that being the cause and then proceed to troubleshooting my O2 sensors and then potentially a new cat. However after doing that I put the distributor back on and now the car won't start. It cranks but no start, ugh!!! I thought I might have installed the distributor in the wrong position so I brought the crank pulley to Tdc and then reinstalled my distributor. Again no start. This morning I was able to use my spark tester before I went to work and I discovered no spark at the plugs(at least on 1 and 2). I know none of this relates to my original question but do you have a direction I could take to continue troubleshooting? I will work back towards the battery and verify power at the coil, igniter etc. I was just wondering if you have any thoughts as to what I may have done during uninstalling/reinstalling my dist. My battery is just over 3 years old and was showing 12.3 v this morning when I looked at it. The car is one that hasn't been driven regularly for the past couple of months so the battery is definitely just sitting there and could be done. I just figured with 12.3 v that I would see some kind of spark so that leads me back to the distributor because that and the battery where the only things that were disconnected or reconnected. Sorry to run on but I wanted to give you as many details as possible. Thank you again for all of your help.
Ask camerontech Your Own Question
camerontech
camerontech
camerontech, Auto Service Technician
Category: Honda
Satisfied Customers: 576
576 Satisfied Customers
Experience: diagnostic auto tech

camerontech is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Thank you very much for saving my daughter and her family a lot of money on her Honda. You are definitely on my list for future help. Thanks, again.

FredUSA

I just heard from my mechanic. You were right...a $45.00 job. THANK YOU!! Your response was received in less than 10 minutes!!

Linda B.USA

Your answers were clear and the diagrams were perfect. Dealer wanted $87 for an hour of labor and even I did it in 15 minutes.

EdUSA

HONDA PLATINUM was great. I really appreciate his help. I was ready to trade my new Honda until he told me to wait until I got 3,000 miles on it and my gas mileage would get much better.

SummerUSA

I took the Power Steering O-Ring service bulletin linked from JustAnswer to my Acura dealer, and not only did they no-charge the o-ring, they also replaced the power steering pump at no cost.

Gary RStevenson Ranch, CA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

< Previous | Next >

Meet the Experts:

Kyle N.

Kyle N.

Honda Master Tech

3,635 satisfied customers

Honda Dealer Tech, ASE Master Auto Tech

John G.

John G.

Honda Technician

2,643 satisfied customers

Dealership tech since 1982. ASE and Honda Master Technician.

Chris (aka-Moose)

Chris (aka-Moose)

Technician

511 satisfied customers

16 years of experience

Marty

Marty

Bosch Master Tech

123 satisfied customers

Bosch Certified Master Technician

Amedee

Amedee

Former ASE Master Technician

1,391 satisfied customers

ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector

Ron

Ron

ASE Certified Technician

381 satisfied customers

ASE Certified Tech 34 years.

thebesthonda

thebesthonda

ASE MasterTechnician

2,299 satisfied customers

26 years experience

< Previous | Next >

Related Honda Questions
Have no power going to my downstream O2/sensor but I do have
have no power going to my downstream O2/sensor but I do have it on the upstream on my 2005 civic. Any idea what the problem is? … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
I have a 2005 Honda Civic 1.7 I am getting misfire on all 4
Hi i have a 2005 Honda Civic 1.7 I am getting misfire on all 4 cylinders and the o2 sensor which is A/F ratio sensor show no activity and heater circuit malfunction. I replaced all 4 plugs to no avail… read more
Gunvir Singh
Gunvir Singh
1,706 satisfied customers
I need to replace both O2 sensors on bank 1. But the parts I
I need to replace both O2 sensors on bank 1. But the parts I got from Advance Auto are labeled downstream front and rear. I think one of these is wrong … read more
Gunvir Singh
Gunvir Singh
1,706 satisfied customers
Fuel system is too rish bank 1. O2 sensor circuit is open o
fuel system is too rish bank 1 JA: Has the vehicle turned into a gas hog? And how does it start -- same as usual? Customer: O2 sensor circuit is open o shorted JA: What is the model/year of your Honda… read more
Matt
Matt
Engineer
Bachelor\u0027s Degree
5 satisfied customers
I was wondering about an estimate about replacing o2 sensors
Hello, I was wondering about an estimate about replacing o2 sensors for a 1999 honda accord LX. I have diagnostic codes for both bank 1 sensor 1 and bank 2 sensor 1 … read more
Jared D
Jared D
Shop Supervisor
Bachelor\u0027s
3 satisfied customers
2005 Honda Odyssey exl. Need to replace all 4 o2 sensors. 2
2005 Honda Odyssey exl. Need to replace all 4 o2 sensors. 2 on each cat conv. Confused on part numbers and names. Upstream, downstream, front , rear. What do i need?… read more
Ron Z.
Ron Z.
Vocational, Technical or Trade Scho
2 satisfied customers
Noise from engine and intermittent smoke from exhaust .. no
noise from engine and intermittent smoke from exhaust .. no performance issues … read more
Gunvir Singh
Gunvir Singh
1,706 satisfied customers
Where would the o2 sensor heater circuit fuse be located on
Where would the o2 sensor heater circuit fuse be located on a 2000 Honda Civic 2.3l. Bank 1 sensor 2. P0141 code still after replacing O2 sensor. … read more
Todd M
Todd M
Owner
ASE Certification
1,299 satisfied customers
Got oil going into front exhaust manifold, Very recent, 2008
I had valve cover gasket's done and the o rings around the spark plugs were not installed properly … read more
Peter Bagley
Peter Bagley
master technition
Vocational, Technical or Trade School
909 satisfied customers
138000,oORiely auto test suggests oxygen sensor, exhaust
138000,oORiely auto test suggests oxygen sensor, exhaust heat shield, engine air intakepipe, oxygen sensor wiring,oxygen sensor connector, spark plu seals. … read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
381 satisfied customers
2005 Accord 2.4, P0135 code, O2 sensor, changed the O2
2005 Accord 2.4, P0135 code, O2 sensor, changed the O2 sensor, still get code, checked all fuses. Now what? … read more
David Gieswein
David Gieswein
Lead Technician
ASE Master certified
103 satisfied customers
Replaced catalytic converter and both o2 sensors.. I also
Replaced catalytic converter and both o2 sensors.. I also looked at a video to properly break in catalytic converter and I'm still getting code p0420.. done a basic tune up. Spark plug, air filter oil… read more
Chad Farhat
Chad Farhat
Owner
Associate Degree
4,012 satisfied customers
2002 accord Need fuse location for front O2 sensor Thanks.
2002 accord Need fuse location for front O2 sensor Thanks … read more
Joecamel90
Joecamel90
Technician
Associate Degree
24 satisfied customers
Cannot get rid of code 1167, new o2 sensors new cat conv.
Hi, cannot get rid of code 1167, new o2 sensors new cat conv. Have 14 ohms on o2 heater. 9.7 volts feeding heater. Car is a Honda 2002 crv. … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
98 civic dx overheated. Replaced head gasket, exhaust
98 civic dx overheated. Replaced head gasket, exhaust manifold, radiator, thermostat, fan motor, and sensor switch. Everything functioning, but fan is not kicking on as temp rises? What could possibly… read more
Amedee
Amedee
Former ASE Master Technician
Vocational, Technical or Trade Scho
1,391 satisfied customers
I have a p0139 code. I have changed the O2 sensor (Denso)
I have a p0139 code. I have changed the O2 sensor (Denso) and the check engine light is still on. (2005 Honda Accord LX 2.4L) … read more
roy
roy
Associate Degree
3 satisfied customers
Code 43 was the latest. I replaced the O2 sensor tonight and
Code 43 was the latest. I replaced the O2 sensor tonight and reset the ECU. I still have an idle problem. it keeps bouncing between 1000 and 1500 rpms when at temp and after load to stop. I have clean… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
I have a 2006 honda crv 2.4, after replace o2 sensors (2),
i have a 2006 honda crv 2.4 , after replace o2 sensors (2), check engine light on code P 2252, i erase it and come back in one minute… read more
Jared D
Jared D
Shop Supervisor
Bachelor\u0027s
3 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x