NEED HELP. CEL Codes p0420 and p1399
 

Not sure if anyone will be able to help me, but I have an 03 Silverstone with about 80k on it. Current mods to the car include AEM CAI and Invidia q300 exhaust. Not too long ago, I started noticing what I thought was a valve tap in the engine. It would come and go intermitantly and usually I wouldn't hear it until it got close to mileage/time to change my oil. The past few times I went to get my oil changed I asked the tech to check it. They said that I had my valves adjusted at my 60k tune up, so not to worry, but said that they would keep an eye on it. Everytime I went I asked them to check it. Evertyime I got the car back they told me the car was running fine.

Recently, my car threw a CEL for the secondary O2 sensor. I took it to the dealership and they said I needed to replace the cat and then quoted me a price of $1,400. I decided to take it to the mechanic that did my exhaust and he said he could get me the cat and replace the sensors @ cheaper cost. He does the work, car runs fine, no more check engine light...until two weeks ago.

The check engine light came on and would come and go even though the car ran fine (one day it was on the next it was off kinda thing). I figured it was a faulty sensor. I let this go on for a week and finally checked the code and it said P0420 (Catalyst System Efficiency Below Threshold (Bank 1). Im like "wtf" is this? The cat is brand new. The next morning on the way to the dealership I dont make it a mile before car starts to run really rough and begins to backfire between 1-2500 rpm, and drives rough at low rpm, but once i got over that rpm range the car ran fine. I get it to the dealer and it throws the same P0420 code and now P1399 (Engine Misfire any cylinder pending).

They hold the car for the day and then tell me they cleared out the codes. The CEL comes back on for P0420 code and that basically I have a faulty cat and need to get it replaced. They mention something about the back pressure and my exhaust possibly being the problem - I know very little about cars but I thought that the larger the exhaust the more it reduced back pressure. I call the mechanic who did the the cat install (its under waranty) and he says to bring the car back to him and he will look at it and replace the cat, but that he thought it might be something else. I go to pick up my car and the dealership tells me the car is running fine now with no sputtering/backfiring - I ask them if they are sure it is OK to drive? "Yes," was the reply. I dont make it down the road 1/2 a mile before the thing starts doing it again. Even worse, as I turn around to take it immediately back to the dealership, the car shuts off on me at 55mph.

Now they quoting my all these different prices in the 3-4k range (including sending something to the machine shop because my valve clips are going bad?). None of this makes sense to me and finally they call me and admit that they cant figure out what is wrong with the car and that they will have to rip the engine down further to give a better diagnosis - At this point i dont trust them anymore.

Has anyone run into anything similar? Can anyone recommend a good mechanic in the Howard County/ Baltimore area?

thanks.

Sorry to hear all issues with your car but all I can say from reading your long story is, stay away from that stealership you are dealing with and your own mechanic sounds kind of shady also. :suspect:

If you posted for help before all of this happened we could have saved you some money but that is besides the point now. I wish I'm close to you but there a lot of good members in this community that can help you out in your area. For me the best way to figure out what is going on is to thoroughly check all your ignition system.

Good luck.

I had the P0420 code when my S had roughly the same mileage as yours, but I had no other symptoms.

I ended up replacing the stock cat with a Berk high flow cat because the Berk cat actually cost less than an oxygen sensor from Honda. It was an easy job, just liquid wrench and then 5 bolts.

I'd recommend the Berk cat, it'll cost WAY less than what the stealership will quote you on an OEM cat. Can't help with your engine sounds though.

I actually had the Berk HFC on there for a while, but then I got tired of listening to the gf (at the time) complain about driving in a race car.

If the sensor is bad replacing the cat isn't going to fix it because you'll be.plugging the same sensor back in. My stock cat are my o2 sensor at around 20k dealership told me it was my problem. Your mechanic sounds shady/lazy. If you pay somebody to do something doesn't matter if it needs to be done or not. It's what you want not what he thinks you should have.

:thumbup: :thumbup:

Did your mechanic replace the cat with an OEM or OEM equivalent? That could be cause for Cat efficiency code... As for the misfire... and now resulting failure -- Has any one checked your ignition coils? They can be problematic as the car ages. I'm just waiting for mine to go. You can swap with someone else pretty easily. Main thing is get the car out of there and get someone that knows the S2000 involved.

Where are you (the car) located?

If you are mechanically inclined I suggest taking the car back home and dropping the cat to see if it is, in fact, going bad. (One way to tell is to hit it with the fist and listen for rattling while it is still on the car). If it is bad - replace with BERK high flow unit.

If the cat seems fine, then check the Bank1Sensor1 O2 sensor. That is the only sensor that can cause the car to behave like you said it does.

I have a computer that I can plug in and monitor both sensors' output. By looking at the data I will be able to tell you exactly what's going on.

Easy.

BTW, monitoring O2 sensor output/hitting the cat is the only thing needed to diagnose this.....it's beyond me that mechanics at the dealership can not diagnose this. : /
(I'm ASE Master tech...just to give my words some credibility)

Oleg- With a majority of mechanics at stealerships today, if the engine doesn't spit out a code that specifically spells out what's wrong and how to fix it, they seem to be lost in the sauce. It's kind of ridiculous. Kind of like, remember when the guys at Advance and Autozone knew a damn thing about cars?

Thanks everyone. I appreciate all of you taking the time to comment.

Olegator - I am in Columbia. The car is now 20 minutes north.

Update - I had the car towed out of there today to a mechanic that works on hondas and has done work on s2000's (a friend of the family recommended this individual). Hopefully, I found someone reliable to work on the car going forward, but that remains to be determined. As far as the previous posts, I am in agreement with everything that has been said. I had the dealership doing the oil changes and what not, mainly because I work so much that I don't have time to do them myself, well let me rephrase that, I am willing to pay to have them done instead of doing them (lazy). To address some of the questions/comments above:

Before I purchased the Berk HFC, I had the factory cat in there and it started to go bad. The thing was making a loud rattling sound when the car was running as all the particle matter or whatever they call it had deteriorated to the point where I could here it moving around in there. I think the movement of this stuff actually caused the demise of my secondary o2 sensor. Instead of paying 1,400 to replace it, I opted to get the berk hfc as a cheaper alternative. I purchased a new secondary o2 sensor as well. When I had the berk hfc in, everything ran fine (minus the intermittent tap I referred to above). The drone eventually started to get to me and I had the berk replaced with an oem equivalent (which i am now realizing may have been a big mistake after reading some of the other boards on here). I should hear back from the mechanic tomorrow morning. I am wondering if:

The oem equivalent cat that I put on the car is crap and has now clogged or is messing with the back pressure somehow which as a result is causing the sputtering/ backfires. I had also wondered about the Bank1 o2 sensor (olegator) and if it might be bad or because the cat isn't working to spec could hypothetically be reading levels that would affect the air/fuel mixture (maybe running too rich??). The mechanic said he would monitor this to determine if that was the case. I am also wondering now if (based on the post above) if one of my ignition coil packs has gone bad. I will post an update tomorrow.

thanks.

honeywheel11, what is your name?
I'm very interested in how your car is doing. I'm local to you, in fact I work in Columbia rt 108. Let me know how things are doing :thumbup:
I'm very sorry to hear about your car.
Not just our cars but a lot of new cars are VERY sensitive now days and they are required OEM parts because they are designed to hold perfect readings. (spark plugs/sensors etc...)

We have numerous customers that declines work to get worked done somewhere else to get slight cheaper and end up coming back (towed) because their car is not running right.

It all depends WHO HELPS YOU and who WORKS on your car. I hope you didn't have any bad experience here @ Jim Coleman Honda :p
But I'm just letting you know that I work local to you and if things aren't going as you plan, let me know and I'd be more than happy to check your car out. I have multiple members here come visit me and I don't let them down :thumbup: I treat their cars like it's mine.

Just letting you know there's some help local if you ever needed! (Olegator and I)
I've heard plenty good things about Olegator so I could vouch him
-Byung

btw, whats your mileage and maintenance history?

It is my understanding that secondary O2 and all related codes are emissions related only. The ECU does no compensation for any thing it reads there. Hopefully one of the ASE guys will confirm.

Thanks Byung!

e3opian, your statement is correct. That's why I suggested that maybe upstream (B1S1) O2 sensor is malfunctioning. That is the sensor that ecu looks at for Air/Fuel mixture readings.

I live in Columbia as well (off of 100). Let us know if you need a hand.

Sorry, my name is Michael.

Well, the Mechanic called me yesterday and told me it needed new plugs. Seemed reasonable since I havent changed them since owning the car even though I heard they are good for a 100k. The car is almost 10 years old though. Anyway, got the plugs installed and picked up the car. The car drives better than when I first bought the thing. I thought my problems were solved. I was driving home on 695 and about 10-15 min into my drive, I throw a CEL (oddly, at the exact moment i plugged my ipod into my head unit, however I doubt that has anything to do with it). I am going to the O's game today so I wont have time, but tomorrow I am going to check the CEL code. I have a feeling that the new plugs took care of the engine misfire code, but that I am still going to have to put an OEM cat back on the car because I really dont want to put the Berk HFC back on. I'm betting the code is another p0420. Olegator, I might need your help if it isnt.

@ s24shoor - didnt take my car to jim coleman - did take it to odonnell and I will never take it back there again. They quoted me 4k of engine work when it seems that the plugs may have been the fix for the p1399. I swear I still hear a faint clicking sound at start up, maybe my TCT. I am not sure though - I would need someone who knows more about the mechanics of the car to listen to it. I have 80k on the car and since I have owned it, I have had to replace my front right break rotor and catalytic converter (which I still seem to be replacing at the moment). The exhaust was ditched for the q300 for my own personal reasons. Other than that, the oil gets changed when it is supposed to (done at odonnell). She has been a great car.

Cold start or warm start? (Or both?)

Also, I'd be glad to swap my OEM cat for the Berk. :thinker:

just want to throw my two cents in.

1. have you checked your spark plugs? (oops, just read your last post).
2. Is the car tuned?
3. Did you check all the sensors inside the car - disconnect and reconnect?

Just few things I would check.

The reason why I asked about your mileage/maintenance history is because I wanted to see if you got basics done. I'm glad spark plugs got replaced. Do you have old spark plugs that they replaced? I just wanted to see what they look like. If not that's alright.
Well keep us updated and feel free to PM me if you want quick communication :tipwink:

Hey Mike,
Looks like you needed new plugs regardless. Let me know, maybe we can meet up during the week and I'll take a look at it.

Hey all, I am Michelle from California and I recently picked up a 2002 Honda S2k in April (116,000 mi). I have the stock CAT on the vehicle with the Invidia exhaust system. Just recently, my check engine light has come up and the reading is P0420. I am slightly concerned that I might need a new CAT. However, a friend of mine works for Honda and he's gonna run a diagnostic check on it to let me know more. Any chance the O2 sensors might need to be replaced rather than the CAT? Subsequently, the car just passed SMOG less than a month ago.

Always remember replace both O2. I would start to replace that CAT first then check the spark plug next, then coil lines. Sometime bad coil will throw u cylinder miss fire code! Anyway good luck on the fix man :tipwink:

Im sorry to hear what happened to your car. Im not that mechanical bit i can certainly vouch for Oleg and Byung ... amazing guys who will go an extra mile to help a fellow s2k.
I highly recommend to take your car to one of them and see if they can help you with it.
Best of luck :thumbup:

If you are in the Howard County area, I would recommend LMT Auto Repair. I've been going to them for almost 10 years and they have always been stand-up guys. They aren't Honda/S2000 specialist or anything, but they've done a good job with my cars. My '02 Lancer is still going strong at 165,000 miles (well, maybe strong is bit of an overstatement) and everyone knows how great Mitsubishi's reputation for quality/reliability is.

I'm in need of great mechanical knowledge. I have an 03 Ap1 which just pass 100,000mi's today. After my work shift I go out and start my car after 10mins of idling I put in reverse to leave and my CEL start flashing. So I check the lights and got 301 n 1399 misfire in cylinder 1 and 1399 is any misfire dectected. I've search but can't seem to figure this out. Plugs or Bad O2/Cat Conv? I'm hoping to do the repairs tomorrow. Thanks for any help and advise

Could be a bad plug but most likely an ignition coil. P0301 is a misfire on cylinder 1. Swap your cyl. 1 coil with cyl. 2. Then clear the codes and drive it until the code sets again. If it is P0302 then you know the coil is causing your problems.

Don't drive the car with the CEL flashing. Flashing CEL is the computer warning you that you are doing damage to your converter. The computer's main job (besides keeping the car running) is to protect the converter. If the light is on, it is usually OK to drive. If the light is flashing, it usually isn't. GG

I just traded my Rsx type s for a 2001 s2000 and only 1500 miles on it in the past 6 years, old guy owned it and didn't have a clue what vtec and never drove above 4k rpm. Anyways, when driving it drives like a dream, not a problem with suspension, sounds nice no cat exhaust, but when I am slamming on the gas it will cut out and bog bag at 5-5500 rpm and jerk back and forth like I have to shift.. If I ease on the gas I can get in higher rpm when in neutral or driving, but obviously shouldn't have to do that, I want to hit vtec so bad in my new car and I am at a complete loss and nobody seems to know anything about it here locally.. The mechanics were laughing at me trying to say they've never even heard of the O2 spacers to put in.. Any help will be greatly appreciated. (I have a no cat exhaust) I have changed plugs, oil, map sensor, clean vtec solenoid and every sensor, cleaned fuel regulators, ran seafoam, drove 700 miles so far. My only codes are po420 and rear right abs speed sensor..

Compression test.