civic10ex

hey guys,

I've been reading the forums for some time now, decided to post because there's been a check engine light that keeps eluding me.

I keep getting a P0420 (catalyst below efficiency threshold) code...the light comes on and then goes away by itself every now and then. the car drives perfectly though.

turning it off with the code scanner only works for a while..I guess after the diagnostics are complete it comes back on.

car is a civic 2010 ex coupe, automatic transmission, sunroof, no NAV screen though. has something like 5000 miles on it. I'm the second owner...from what I know, the previous owner replaced a TPMS sensor because that light would not go off and he may have caught some front side damage that did not trigger the airbags.

i've ran the diagnostics with the scanner and there have been no engine misfires...I cleaned the injectors, changed the spark plugs, checked emissions (no issues there, still clean), checked the sensors (good as well), and the scanner says the EGR valve is ok. however, I keep getting the check engine light with the P0420 code.

last time it shut off was after driving on the freeway for some time at night...drove it again next morning. not sure if that has something to do with it.

the car was stored for a couple of months...not sure if that caused some buildup in the catalytic converter. the only other suspect signs i've seen are an occasional clicking/soft knocking noise when backing up or going forward in short distances and some scratching noise when turning the key under cold weather.

anyway, these are the specs from the freeze frame data...seems like at that time the mix was trying to go lean

any help is much appreciated...I've been thinking about pouring in a bottle of cataclean and if that doesn't work then i'd have to change the catalytic converter...just trying to figure out if there's something else at play here.

DTCFRZF P0420
FUELSYS1 CL (closed loop)
FUEL SYS2 NA
LOAD_PCT% 76.9
ETC (CELCIUS) 87 / (FAHRENHEIT) 188.6
SHRTFT1 % -5.5 (SHORT FUEL TRIM GOING LEAN)
LONGFT1 % -11.7 (LONG FUEL TRIM GOING LEAN)
MAP (KPA) 72
RPM / MIN 1575
VSS (KM/H) 68 (MI) 42.5
SPARKADV 30
IAT (CELCIUS) 36 / (FAHRENHEIT) 96.8
MAF (G/S) 13.58
TP % 21.2
RUNTM (SEC) 379
EGR PTC % 42.7
EGR ERR % -0.8
EVAP PCT % 99.2
FLI % 100
BARO (KPA) 90
VPWR (V) 12.475
LOAD ABS % 54.7
EQ RAT 0.953
TP R % 12.9
TP B % 37.3
APP D % 34.9
APP E % 17.3
TAC PCT % 13.7

ezone

Stop touching the car.

You have 3/36 (USA) warranty that probably is still in effect (except for accident damage, if it can be proven that it is the cause of a problem, and the car wasn't totaled)
You have 5/60 powertrain warranty

The CAT and the PCM is covered under warranty for 8 years/80,000 miles. Take it to a dealer.

civic10ex

thanks man but the thing is i'm not in the US now...so none of that would be an option under this scenario

ezone

Explain this further.

Where are you now, and why?
What market was the car made for?




The car probably needs a cat, at any rate, to keep the light off (95% sure but really should have a few checks done first).
You also SHOULD figure out what caused the cat to go bad this soon. It could have been related to an accident (very likely). Any misfiring that would allow raw fuel to be dumped into the cat could have ruined it (overheated it).

civic10ex

ok, car is ca odbii compliant, so i guess that's california emissions standards. car was manufactured in canada and sold at a dealership in texas.

some guy bought it and brought it to costa rica...that's were i bought it. they say that gasoline here is rather filthy.

what other checks would you recommend before changing the cat? yeah my guess it's either the accident did something to the cat or it has to do with the time it spent parked...the scanner shows no misfires...and the car was actually taken to the local dealership when it arrived here...after that it was stored for a few months.

ezone

Ok, "filthy" gas, I have no idea what that entails, I would guess that could poison a cat if it had enough contaminants.

Does the car have to pass an emissions test?

DO other people there have problems with the catalytic converters on newer cars there too, or not? If not, then I would assume the fuel is ok to use and it wasn't the cause of the cat failure.

SO you are down to accident damage. Was the converter physically hit or damaged in the accident? That could damage the substrate and render it ineffective.

That's most of my concerns, figuring out what killed the cat.
The other check I would do is fuel control checks and briefly watching the rear O2 sensor on a datalist.



I gotta ask, what scantool did you use to get this FF data?



Something stands out here:

SHRTFT1 % -5.5 (SHORT FUEL TRIM GOING LEAN)
LONGFT1 % -11.7 (LONG FUEL TRIM GOING LEAN)

EVAP PCT % 99.2
FLI % 100

It isn't "going lean" as you think. The PCM is taking away a percentage of fuel from the base calculation. As if it were slightly rich and the computer is trying to lean it out.
The Fuel level being at 100% makes me wonder if you keep adding fuel to reach the next dollar after the pump shuts off. This can flood the charcoal canister with raw fuel and cause the fuel trim numbers you have.



BARO (KPA) 90

You are somewhere around 1000' above sea level when this code set?

ezone

Oh yeah, leaving the car parked had absolutely nothing to do with the cat code.

civic10ex

yep something like 1150 mts above sea level

yeah no idea about filthy gas...that's just what people say. i guess it's not killing cats all over the place but maybe the time the car spent parked caused some sort of buildup or something like that.

the car actually already passed an emissions test here (although i'd guess the standards would not be as strict as in the US)...and I performed another one at a shop and the values were good still. the official test also entailed a general mechanic check and it passed with no issues.

i am not sure if the accident entailed a hit to the cat....shell looks normal and the cat has a rust like color....operating temps have ranged from 200 C / 392 F to 550 C / 1022 F

i watched the o2 sensors with an oscilloscope at a shop...top sensor fluctuated like crazy and the bottom sensor was flat most of the time...although a check with a code scanner said they were both showing equal volt readings

the freeze frame data came from an autel maxiscan509 scanner..it actually graphs the sensors and shows lots of data...pretty handy imo although i guess its still below professional grade scanners

the times i've filled up at the gas station i've just poured in a fixed amount...not going for the extra juice there as sometimes people do because some extra fuel can still be added in. when this code showed up...i had just filled up the tank...in fact i was coming from the gas station.

civic10ex

btw these were the gas readings from the official emissions test

COR= 0.12%V
HCR = 19 ppm
COA = 0.02%V
V HCA = 12 ppm
CO2R = 14.40%V
CO2A = 14.60%V

ezone

yeah no idea about filthy gas...that's just what people say.

Ok, right at the top of the P0420 diagnosis chart is this statement:

"Poor quality fuel can cause these DTC."

So stop right there.
No point in replacing a high $$$ cat if crappy fuel is just going to ruin it every 5000 miles.
(A new cat lists for $455 USD, plus a core charge, plus gaskets, plus hardware. And add shipping and foreign currency rates.)

No physical damage, and the car has passed your emissions test.....I'd probably ignore the light for the moment. I would also want access to a scanner so I can periodically check for new codes though.

I would REALLY want to run some KNOWN GOOD FUEL in it, just to see how much effect that has on this situation. Before putting any parts on.


Or you could put a new cat on it. See how long it lasts. That's up to you.




i guess it's not killing cats all over the place but maybe the time the car spent parked caused some sort of buildup or something like that.

Parking the car had absolutely nothing to do with it.




the car actually already passed an emissions test here

Was the CEL on when this test was done???



(although i'd guess the standards would not be as strict as in the US)...and I performed another one at a shop and the values were good still. the official test also entailed a general mechanic check and it passed with no issues.

Was this a one-time event when the car came into the country, or is this an annual inspection?



i am not sure if the accident entailed a hit to the cat....shell looks normal and the cat has a rust like color....operating temps have ranged from 200 C / 392 F to 550 C / 1022 F

i watched the o2 sensors with an oscilloscope at a shop...top sensor fluctuated like crazy and the bottom sensor was flat most of the time...although a check with a code scanner said they were both showing equal volt readings

The top sensor is an Air/Fuel Ratio sensor, and it doesn't work the same way as a regular O2 sensor.

What really matters is the PCM, it does the testing. You can do all the testing you want, but the PCM decides whether or not the cat passes its tests and keeps the light off.





the freeze frame data came from an autel maxiscan509 scanner..it actually graphs the sensors and shows lots of data...pretty handy imo although i guess its still below professional grade scanners

Interesting.
I just recognized that your FF data is a quite a bit better than generic.

I have multiple laptops with HDS programs on them. I am a dealer tech. I really don't know what is available in the aftermarket scanners anymore.

the times i've filled up at the gas station i've just poured in a fixed amount...not going for the extra juice there as sometimes people do because some extra fuel can still be added in. when this code showed up...i had just filled up the tank...in fact i was coming from the gas station.

Ok, I was thinking the fuel trims could have been coming from the canister. The trim numbers COULD be caused by poor fuel quality too.Would be interesting to see what a good quality fuel would do, before tossing any parts at it.



btw these were the gas readings from the official emissions test

COR= 0.12%V
HCR = 19 ppm
COA = 0.02%V
V HCA = 12 ppm
CO2R = 14.40%V
CO2A = 14.60%V
Hey, if the locals are happy with the numbers, I'd probably leave it alone.

civic10ex

yeah what i've heard about the gas it this: high sulfur content and the gas stations never clean up their underground deposits...some people claim they've taken out their gas filter only to find it loaded with crap.

not sure if the CEL was on...my guess is it wasn't...the test is performed each year and i'm not sure if they require the light to be off for it to pass (my guess would be no). about the scanner...yep i did some research before buying one and one review from a retired mechanic convinced me on getting this one...cost something like USD70.00 and it shows lots of live data...i actually drove watching a graph on cat temp...it would drop a lot when i didn't press the gas pedal and it would go up...when accelerating.

yeah and when i checked again i think the HCR reading was even lower..something ranging from 10 to 18 PPM...unburned fuel does not seem to be flowing in at least on a consistent basis

you think something like an octane booster could serve as a proxy for better quality gas?

ezone

yeah what i've heard about the gas it this: high sulfur content and the gas stations never clean up their underground deposits...some people claim they've taken out their gas filter only to find it loaded with crap.

That may be 2 separate issues.
Sulfur would be one, that's probably contaminants at the refinery level
Dirt and other contaminants is the other, at the distribution level.

All are bad.



not sure if the CEL was on...my guess is it wasn't...the test is performed each year and i'm not sure if they require the light to be off for it to pass (my guess would be no).

You ought to find this out for sure before you decide what to do with this.



about the scanner...yep i did some research before buying one and one review from a retired mechanic convinced me on getting this one...cost something like USD70.00 and it shows lots of live data...

Nice. Sounds TOO cheap. Makes me wonder what its limitations are.


i actually drove watching a graph on cat temp...it would drop a lot when i didn't press the gas pedal and it would go up...when accelerating.

There is no temp sensor for the cat. It is a data value that is inferred, it is only programmed into the PCM and changes values based on a model.

yeah and when i checked again i think the HCR reading was even lower..something ranging from 10 to 18 PPM...unburned fuel does not seem to be flowing in at least on a consistent basis

It would take a dead miss to do it, or raw fuel poured through while it was running and hot.
Wait a sec....If there is a dead miss, the PCM strategy is to shut off the fuel injector. So it almost CAN'T be this.
You would have far more codes if it had misfires.

So back to fuel quality.


you think something like an octane booster could serve as a proxy for better quality gas?

Nope.

Also, high octane does not mean high quality.

Word: http://www.toptiergas.com/

jordan1794

Trust e-zone about top tier, it really does make a difference.
<Convinced Skeptic

ezone

Dude is outside of the normal distribution channels though.

jordan1794

Yeah, bummer...
Is there any tool you can get to test the quality of gas? Perhaps drive around one day and see which station has the best...

ezone

LOL,

No, there isn't any good way for the average Joe to test fuel.

Checking for an approximate percentage of Ethyl Alcohol content is simple and easy, but what OP apparently needs is not that simple.

You would have to send samples to a lab that deals with fuels.

sdaidoji

iTrader: (1)

filthy gas - some countries have the truckers adding solvents to make some extra bucks (one trip to the distribution center, drive to twice gas stations than it would normally...)

civic10ex

I do think I got the rotten egg smell once...not sure if it was my car or another one in the line though

talking to the local mechanics all thoughts focus on the cat converter...and of course...there's always the dude that has a friend that can swap it for another one (even a motorcycle cat) or the guy that imports some "cartex" carb and epa compliant cats for which "he does not guarantee any work"

ezone

Rotten egg smell comes from sulfur in the fuel.


Your cat already passes the local emissions test, right? This is why I might ignore the light, unless the light MUST be off in order to pass the local emissions test.
At any rate, I sure wouldn't want to buy more than one good factory cat.

The PCM has far more stringent testing going on than your local test.
The CEL can be on LONG before the cat is bad enough to actually fail an emissions test.

The PCM will not be happy with any aftermarket cat. There is a reason the guy won't warranty his work.

Are all of your trips extremely short? How about doing an extended high speed run?

There is no legitimate way to clean poisons from the substrate that I know of, no matter what snake oils you can find at parts stores or on the internet say. You can try all you want, but don't expect much.

If it is loaded with carbon, some high speed running may help.

civic10ex

Yep it passes the local test and I just learned the next one is due until 2013...turns out newer vehicles get tested every 2 years.

Yep most of my trips are short....something in the range of 10 mins with lots of stops because of speed bumps along the way. I'll try the extended high speed run.

Last time the light turned off by itself I'd been driving longer distances the previous night.

civic10ex

Been some time...the light has turned off by itself and come back after some time...i believe the first time was after not using the car for a week and the other two times it was after unusually hard driving sessions on the freeway

civic10ex

Turns out new cars have been having catalyst problems here

http://www.fijatevos.com/latest-arti...th-hazard.html

The government had been importing fuel with high levels of mmt...i guess that thing is responsible for my check engine light then...still...since the car has less than 10k miles on it i am still passing local emissions tests with flying colors!

civic10ex

sorry for bumping an old thread but i had an update that might be interesting.

i replaced the downstream oxygen sensor and the light has not come back ever since. although it has only been one week the light should have returned as it usually did

most interesting is that i have caught a pending p0420 code twice during this week with a new o2 sensor. it cleared itself the first time and it came back today but still no light

ezone

The "pending" code set means it has failed the self test once, but has not yet failed the second self test to turn on the CEL.

As soon as it fails the cat monitor test twice in a row, it will turn the CEL on again.

The monitor runs one time per applicable drive cycle in which all conditions are met to run the test.
So it takes failing the cat monitor self test 2 consecutive times over 2 drive consecutive drive cycles to see the CEL come on.



Any chance the fuel quality is improving?

civic10ex

no clue on the gas quality...no changes other than replacing the air filter, spark plugs and cleaning injectors last year

ezone

Someone posted this in another forum

http://www.converterwarehouse.com/te...rter-&News=100

civic10ex

yea but I'm not sure if places other than the dealership have the right equipment...or at least they'd charge more than I'd like to spend for it.

btw I've been noticing a couple of things...my ST and LT fuel trims are way negative...ST moving in a range from -5 to -9 most of the time and LT slower in a -7 to -9 range...the difference between both is good but the sum is way different from 0...I'm considering changing the upstream sensor now...the A/F mix one

on the other hand...my lambda equivalence is almost always at 1, with the m.ix at 14.7 or 14.6 to one most of the time....but the trims confuse me. the MAF sensor is squeaky clean though

finally, I've been looking for some patterns regarding the pending codes now that I changed the downstream sensor....the least common denominator seems to be that I drove at cruise speed for several stretches both times...not even pressing the gas pedal..first time was at night after a cold start but the second one was in the middle of the day with hot weather...thinking maybe this thing is going in the direction of oxygen storage being curtailed by low quality gas

ezone

About the only thing different I can think of is a dealer has is factory scanner (or maybe not in your case, depending on the market and country of origin of the cars). And they can do the warranty work if applicable (maybe, maybe not-- because yours was imported?)

Seems like the lowest wage workers do the majority of the work no matter where you go......

It's within 10%, I don't worry much about it but I prefer to see within 5%. IIRC it has to exceed something like 19% for some period of time in order to set a fault code.

Don't add LT and fluctuating ST trim numbers together, it doesn't quite work that way.


Poor fuel quality could easily be the cause of the trim numbers.
Poor fuel quality not only can poison the cat, it can poison the O2 sensors.
TEL (tetra ethyl lead) is a poison, so is many forms of silicone. Both will ruin O2 sensors.

Not cheap, and the cars don't like non-OEM parts.

Warranty?

The computer still has control of the fuel mixture, it is still able to do its job as designed. No worries.

So far here, the biggest issue is when someone puts a cheapo filter in and a bug gets through and blocks the MAF holes. I have not seen issues with dirt the way older Ford MAFs did.

Every time I have seen a bug in the MAF, the car didn't run at all or ran extremely lean. (positive fuel trims)
My guesses: Contaminants clogging the pores of the substrate....or poisoning by unwanted chemicals in the fuel.



The OSC sounded closest.

Here's copy and paste from the Honda info:
The engine control module PCM fluctuates the air/fuel ratio temporarily to detect the performance of the TWC (three way cat) and measures the degree of fluctuation in the secondary HO2S output. If the accumulated value for a set time is too great, deterioration of the performance of the catalyst is detected, the ECM/PCM detects a malfunction and stores a DTC.

ezone

My HDS scanners for North American market cars would not work with European market cars, nor Japanese market, nor Aussie, S.A., etc.
Same for the other way around. It's a big issue for techs in areas where cars can be imported from all over the world.

Different communication protocols in different countries and markets.
Different equipment and emissions requirements in each market and area.

civic10ex

so the light finally came back after 12 days...again after temperatures had dropped considerably. got this freeze frame data from the torque app for android (i sold the scanner)

im thinking that my next move will be taking a look directly into the cat...bring it down and finally see if it has actual physical signs of deterioration...if it does well ill have to bite the bullet and get a new one

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 38.824 %
Engine Coolant Temperature = 71 °C
Fuel Trim Bank 1 Short Term = -6.25 %
Fuel Trim Bank 1 Long Term = -11.719 %
Intake Manifold Pressure = 4.786 psi
Engine RPM = 1,306 rpm
Speed (OBD) = 56 km/h
Timing Advance = 6 °
Intake Air Temperature = 25 °C
Mass Air Flow Rate = 5.5 g/s
Throttle Position(Manifold) = 16.078 %
Run time since engine start = 258 s
EGR Commanded = 0 %
EGR Error = 0 %
Fuel Level (From Engine ECU) = 61.569 %
Barometric pressure (from vehicle) = 12.908 psi
Voltage (Control Module) = 14.325 V
Engine Load(Absolute) = 23.922 %
Commanded Equivalence Ratio(lambda) = 1
Relative Throttle Position = 5.882 %
Absolute Throttle Position B = 32.941 %
Accelerator PedalPosition D = 20.392 %
Accelerator PedalPosition E = 9.804 %


End of report.