P0420 Code AGAIN!!!
Okay, this is my least favorite number. This is my third time recieving this code within 9 months. The first time I replaced the o2 sensor before the monifold. I then got the same error three months after and replaced my other oxygen sensor along with the previous one. Therefore I have had two new o2 sensors in my car for the last 3 months. They are the bosch universal ones. I read after installing that those aren't the best to get, but they are the cheapest. Anyway, I am now wondering if my cat is bad and what I should do about these stinkin o2 sensors. Please help me fix this problem so it won't come back again. :confused:
Thanks, Andrew |
Why are you replacing O2 sensors? P0420 is a catalyst efficiency code.
Edit: In my AV6, anyway. What engine do you have? |
Its a V6
The code states that "Catalyst System Efficiency Below Threshold", I was told this was a problem with the o2 sensors from reading other forums. Problem seemed to go away after I replaced the sensors but then came right back months later. What should I do??
Oh yeah, its also automatic. Same year as yours too (1998). Do I need to replace the cat converter? Tranny is also starting to slip a bit, errrr |
Originally Posted by Vladi17
The code states that "Catalyst System Efficiency Below Threshold", I was told this was a problem with the o2 sensors from reading other forums. Problem seemed to go away after I replaced the sensors but then came right back months later. What should I do??
Oh yeah, its also automatic. Same year as yours too (1998) DTC P0420: Catalyst System Efficiency Below Threshold 1) Reset the ECM/PCM. 2) Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on. 3) Except F23A4 SULEV engine: Test-drive at 40 - 55 mph (64 - 88 km/h) for approx. 2 minutes . Then decelerate for at least 3 seconds with the throttle completely closed. Then reduce the vehicle speed to 35 mph (56 km/h ), and try to hold it until the scan tool indicates FAIL or PASS as the TWC test result. F23A4 SULEV engine: Test-drive at 50 - 55 mph (80 - 88 km/h) for approx. 2 minutes . Then decelerate for at least 4 seconds with the throttle completely closed. Then accelerate to 55 mph (88 km/h ), and try to hold it until the scan tool indicates FAIL or PASS as the TWC test result. Is the test result FAIL? YES - Check the three way catalytic converter (TWC). If necessary, replace the TWC. NO - Intermittent failure, system is OK at this time. So if P0420 comes on and it's the only code, either replace the TWC or have your Honda dealer (or someone else) test the TWC to see if it's bad or not. If there are multiple DTCs, troubleshoot those first. I only have P0420 :( I'll copy this in the DTC thread. |
Twc??
Sorry, I'm a little confused by your reply. Not sure what the Three-Way Converter (TWC) is. Also not sure what F23A4 means, could you please go a little bit more into details about what all this means. Also, I don't have a scan tool, I went to autozone for the reading. Should I buy one and have it plugged in while I drive?? I'm a little confused. Thanks for your quick response and all your help.
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sounds like you should try the o2 defouler trick.
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o2 defouler trick?
Could you be a little more specific???
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Originally Posted by Vladi17
Sorry, I'm a little confused by your reply. Not sure what the Three-Way Converter (TWC) is. Also not sure what F23A4 means, could you please go a little bit more into details about what all this means. Also, I don't have a scan tool, I went to autozone for the reading. Should I buy one and have it plugged in while I drive?? I'm a little confused. Thanks for your quick response and all your help.
The scan tool referred to is a Honda tool that allows them to scan your entire ECU and get all sorts of data. I believe you can purchase one but they're very expensive. |
Thanks for the help
Okay, I think I'm gonna replace the cat converter, seems to me that has to be the problem since I replaced the both 02 sensors. Found one for around $140 (3.0 V6 Direct-Fit), if you know of cheaper please let me know.
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Originally Posted by Vladi17
Okay, I think I'm gonna replace the cat converter, seems to me that has to be the problem since I replaced the both 02 sensors. Found one for around $140 (3.0 V6 Direct-Fit), if you know of cheaper please let me know.
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Originally Posted by Vladi17
Could you be a little more specific???
Originally Posted by notoriousB
yup, we did this for a grand total of $3.99+tax i believe!
get this "help" part at your local parts store: 18mm defouler - comes in a pack of 2 here's the package and the two defoulers screwed together http://www.imagestation.com/picture/...2/f3fab2fb.jpg i drilled out the bottom of one with a 1/2 inch drill bit - go slow, use lots of oil, it's thick i don't have any pictures of the one drilled out alone, but here's two pics of the final product, one from the bottom one from the top. in the second pic you can see how it was drilled. the drilliing is done to be able to fit the o2 sensor thru the 1st defouler. http://www.imagestation.com/picture/...d/f3fab2ec.jpg http://www.imagestation.com/picture/...a/f3fab2da.jpg final product all installed, and skabone confirms "it works!!" :D http://www.imagestation.com/picture/...d/f3fab2c9.jpg had to persuade the heatshield slightly to clear the new longer o2 sensor but that's no problem. |
This is the cat I'm lookin at buying, looks alright, not off ebay.
What do you think?? http://www.convertersexpress.com/ind...ig=&cylcount=6 |
good luck with that $140 cat as you will most likely get the P0420 code again as aftermarket cat. won't burn clean enough to keep the light out as new cat. for the 2.3l motor is $2,000 for a california car as they are ULEV the V6 is cheeper but still lots of money...just use the fouler plug trick with the stock cat. as you will still need to the fouler trick for the aftermarket cat. also if you are from california it's illegal to put a aftermarket cat. on a 0BD2 car.
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There are two O2 sensors on our car and where you got confused is you replaced the O2 sensor on our exhaust manifold. It manages the air/fuel ratio. The code you keep getting means your cat efficiency is below the acceptable threshold, which is determined by the second O2 sensor that's at the back of your cat. Don't pay for a new cat and if you do, get an OEM replacement, not some high-flow cat. You're gonna lose power if you do. I would say just do the spark plug defouler fix that Skabone posted. It's very simple and will cost probably $5.
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Originally Posted by stereo
good luck with that $140 cat as you will most likely get the P0420 code again as aftermarket cat. won't burn clean enough to keep the light out as new cat. for the 2.3l motor is $2,000 for a california car as they are ULEV the V6 is cheeper but still lots of money...just use the fouler plug trick with the stock cat. as you will still need to the fouler trick for the aftermarket cat. also if you are from california it's illegal to put a aftermarket cat. on a 0BD2 car.
Magnaflow aftermarket cats DO NOT put out check engine lights! Try the defouler trick though if you please, I'd like to see if it actually works for you. My opinion is that your cat is worn out, but try the $5 fix first like these guys say. |
just keep in mind that cats carry an 8 year or 80k warrenty from the factory.
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Skabone69, Could you explain the "defouler" a little? Does this prevent the O2 sensor/s from fouling? Did you install on both upstream and downstream O2 sensors? How long has this solution worked for you?
thanks |
Originally Posted by TexasHonda
Skabone69, Could you explain the "defouler" a little? Does this prevent the O2 sensor/s from fouling? Did you install on both upstream and downstream O2 sensors? How long has this solution worked for you?
thanks |
Originally Posted by skabone69
it pretty much tricks the secondary 02 sensor and tells the car that the emmissions are running fine. you'll only need to run the defouler for the 02 sensor that is in the cat. I've had the defouler on my car since May and I haven't had a problem. in fact I'm getting better milage now. I was getting 330-360 miles on a tank of gas, now I'm getting 390-410 miles on a tank of gas.
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The post-converter O2 sensor monitors O2 content out of the catalytic converter to assess whether converter is performing OK. It can be fooled by exhaust leaks or missing engine, and even too sensitive software assessment of sensor input can cause problems. The post-coverter sensor has no bearing on fuel-air ratio, which is controlled by pre-converter sensor input to ECU.
regards |
i have the same exact problem with Vladi17....it sucks..do u guys think this would couse any problem on my motor? i havnt replace my secondary 02 yet but i will this saturday..the problem is i drive 45min away from work which is 50miles....i have 3 more days on replacing it..u guys thick its safe?
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Originally Posted by k4sp3r
i have the same exact problem with Vladi17....it sucks..do u guys think this would couse any problem on my motor? i havnt replace my secondary 02 yet but i will this saturday..the problem is i drive 45min away from work which is 50miles....i have 3 more days on replacing it..u guys thick its safe?
My PO420 code has been on for 30k miles. Relax. |
Originally Posted by Vladi17
(Post 2511779)
Okay, this is my least favorite number. This is my third time recieving this code within 9 months. The first time I replaced the o2 sensor before the monifold. I then got the same error three months after and replaced my other oxygen sensor along with the previous one. Therefore I have had two new o2 sensors in my car for the last 3 months. They are the bosch universal ones. I read after installing that those aren't the best to get, but they are the cheapest. Anyway, I am now wondering if my cat is bad and what I should do about these stinkin o2 sensors. Please help me fix this problem so it won't come back again. :confused:
Thanks, Andrew |
Originally Posted by kaoshen
(Post 3099696)
I had the same problem with my 2000 Honda Civic EX automatic. P0420 COULD be bad 02 Sensors OR it could be the Catalytic converter! I replaced my 02 Sensor and light stayed on. So replaced the Catalytic converter and Cleaned out both 02 Sensors and problem solved!! Civic EX Cats are cheap to replace ($270). Civic LX and DX and CX have catalyctic converter connected to exhaust manifold as ONE PART and that alone costs $960 at hte DEALERSHIP!! Take it form a used car dealer, I've had many of these.
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Originally Posted by totalimmortal
(Post 3100162)
Good job bringing a thread back from last year, moron.
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Geeeez...take a pill.
Originally Posted by totalimmortal
(Post 3100162)
Good job bringing a thread back from last year, moron.
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Again, this thread is from last year.
Get out troll. |
How old are you boy!
Originally Posted by totalimmortal
(Post 3462614)
Again, this thread is from last year.
Get out troll. Anyway, im getting a P0420 code on my 98 Accord EX and am currently looking for a soil cat that will not throw any codes once installed. I understand Magnaflow direct fits are good. Are Bosal direct fits any good aswell? ....and please, no rage and/or idiocy with replies. |
Originally Posted by big2000dave
(Post 3463800)
Shut your hole boy and go get your passy. This fit of yours is going nowhere. Everyone is here for help and knowledge on their fav. Hondas. Tis better to bring back an old thread than start a new one. So explain to me son, what your prob? Can't wait to hear it :rolleyes:.
Anyway, im getting a P0420 code on my 98 Accord EX and am currently looking for a soil cat that will not throw any codes once installed. I understand Magnaflow direct fits are good. Are Bosal direct fits any good aswell? ....and please, no rage and/or idiocy with replies. if you would have read the whole thread and my comment from 9/21, you might realize that my post could help you. might want to try out my suggestion first before you get a new cat.;) |
Originally Posted by skabone69
(Post 3463852)
wow, what a way to welcome yourself to the community:rolleyes: what's a passy? Who the hell do you think you are being an e-thug? There is no better way to alienate yourself from a forum than to type in the tone your are typing.
if you would have read the whole thread and my comment from 9/21, you might realize that my post could help you. might want to try out my suggestion first before you get a new cat.;) |
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