My car just came up with a check engine light. Threw my friends scanner on there and it gave me this code? P0455 EVAP Emissions Control Leak (LARGE).....
Anyone know what this is before I take it to the dealer?
Well....with a code like that i would check to see if the gas cap is on and firmly secured first.......make sure you when you put in on it clicks a few times
yes check the gas cap, buy a new one to fry it out to see if it'll fix it, if it won't work then return it. Sometimes it looks good but its not, if you know what i mean.
Also on the cavaliers/sunfires if you look on the back axle theres a black box, there should be wires going to there, the wires are notorious for being damaged.
I get this code P0420....... and i delete it...but it comes back.....again and again! Anyone have/had this problem please help. THANKS in Advance!!!
I had a P0420 once......cat effiecency below threshold....mine kept coming on after i cleared it....then i looked into it and found that the converter itself was falling apart on the inside...i could hear crap knocking around......but you could have a bad o2 senosr.......I think the warranty on a factory GM converter is lik 8 yrs 80,000 miles....not to sure....might want to check your manual....i had mine replace at about 40K or so at GM
120000+ miles any other options?
Well i checked my gas cap...and as you said it seems to be not sealing tight. But where can I buy a new gas cap for my car?
PhilioZ24 wrote:I had a P0420 once......cat effiecency below threshold....mine kept coming on after i cleared it....then i looked into it and found that the converter itself was falling apart on the inside...i could hear crap knocking around......but you could have a bad o2 senosr.......I think the warranty on a factory GM converter is lik 8 yrs 80,000 miles....not to sure....might want to check your manual....i had mine replace at about 40K or so at GM
That's the same problem I'm having on my 97 2.4L. The car passed emissions yet the P0420 light keeps coming on, even after replacing the post-cat O2 sensor. I'm stumped, if the cat was bad it wouldn't have passed emissions.
J P wrote:PhilioZ24 wrote:I had a P0420 once......cat effiecency below threshold....mine kept coming on after i cleared it....then i looked into it and found that the converter itself was falling apart on the inside...i could hear crap knocking around......but you could have a bad o2 senosr.......I think the warranty on a factory GM converter is lik 8 yrs 80,000 miles....not to sure....might want to check your manual....i had mine replace at about 40K or so at GM
That's the same problem I'm having on my 97 2.4L. The car passed emissions yet the P0420 light keeps coming on, even after replacing the post-cat O2 sensor. I'm stumped, if the cat was bad it wouldn't have passed emissions.
When doing emissons testing older cars are aloud some gap space wear and tear on the motor ..we all know that a 97' 2.4L isn't going to run like a 2006 cobalt There are specs that they use if it is your o2 or your converter throwing a code up your car might be running on a "open loop" program And it still might pass on the test still. One bad side is the honey-comb inside you converter might get worst and break-up inside i had this happen once on a 90' Daytona 3L. The honey-comb ended up stuck in the pipe the car back-fired the cad got white hot and the undercoating caught fire ..ever try throwing water under a car! if your hearing clang clang like rocks jumping around evertime you hit a bump it's most likely that cad..If you already passed your e-test and it's good for 2 years? (depends on where you are) and you replaced the o2 i'd go with a pipe and lose the cad till you can 1 come up with a new one. Or wait till e-test time...did ya remove the battery post to clear the code are clear it with the obd2 scanner?
http://img86.imageshack.us/img86/4235/jim25ek.jpg
Not sure if this helps anyone, but I used to have the EVAP code come back on again and again, i replaced the valve cover gasket after checking everything else and the light went off by itself and hasn't come on since.
Jimmaaaay! wrote:J P wrote:PhilioZ24 wrote:I had a P0420 once......cat effiecency below threshold....mine kept coming on after i cleared it....then i looked into it and found that the converter itself was falling apart on the inside...i could hear crap knocking around......but you could have a bad o2 senosr.......I think the warranty on a factory GM converter is lik 8 yrs 80,000 miles....not to sure....might want to check your manual....i had mine replace at about 40K or so at GM
That's the same problem I'm having on my 97 2.4L. The car passed emissions yet the P0420 light keeps coming on, even after replacing the post-cat O2 sensor. I'm stumped, if the cat was bad it wouldn't have passed emissions.
When doing emissons testing older cars are aloud some gap space wear and tear on the motor ..we all know that a 97' 2.4L isn't going to run like a 2006 cobalt There are specs that they use if it is your o2 or your converter throwing a code up your car might be running on a "open loop" program And it still might pass on the test still. One bad side is the honey-comb inside you converter might get worst and break-up inside i had this happen once on a 90' Daytona 3L. The honey-comb ended up stuck in the pipe the car back-fired the cad got white hot and the undercoating caught fire ..ever try throwing water under a car! if your hearing clang clang like rocks jumping around evertime you hit a bump it's most likely that cad..If you already passed your e-test and it's good for 2 years? (depends on where you are) and you replaced the o2 i'd go with a pipe and lose the cad till you can 1 come up with a new one. Or wait till e-test time...did ya remove the battery post to clear the code are clear it with the obd2 scanner?
Yep, code's been cleared a couple times. Keeps coming back on, but the weird thing is that I get (2) instances of the P0420 cat efficiency below threshold. This thing boggles my mind.
Ah ha.. most models with a OBD2 are equipped with two oxygen sensors one "an upstream sensor" mounted in the exhaust manifold, And a downstream sensor mounted in the exhaust pipe (after the catalytic converter) this might be where your problem lies between the cat flange and the cat ....after cold start the car runs in a open loop after warm up the car go's into a closed loop by reading the sensor info if any are not working the PCM remains in a open loop and the engine light stays on. There's away to check and see if the downsteam o2 is working are not but ya need a ohmmeter ya got one???
http://img86.imageshack.us/img86/4235/jim25ek.jpg
I know there are two O2 sensors (exh. manifold and post-cat), but are you saying these two code instances mean that both are malfunctioning? I just had the post-cat sensor replaced, not sure if it was a Delco one though. But no, I don't have an ohmmeter.
if your getting code PO420 cat sys eff below threshold...(bank 1) not (bank 2)<<P0430 I Think is the first upstream o2 ..you can do a ohm's test on the o2 to see if the volts are working and that would tell ya that the o2 is still good are not is the 420 code the only code popping up? did you replace the last o2 near the cat? the other one wouldn't set this code
http://img86.imageshack.us/img86/4235/jim25ek.jpg
yea, it's 2 instances of bank 1, replaced the O2 sensor after the cat not in the exh manifold.
assuming the 02 is working you have a leak ( The downstream o2 detects oxygen content after the exhaust has been catalyzed) If there's a leak or the cat is broke up or gummed up this would set the o2 off So your down to getting the o2 tested, looking for a leak between the first flange after the ex manifold and before the downstream o2 , are replacing the cat. i'm thinking the cat
http://img86.imageshack.us/img86/4235/jim25ek.jpg
Yea, who knows, thanks for the help. I'll have the mechanic keep working on it until it's fixed.
I just payed out 1975 bucks to replace this timing chain plus othe misc. items on the list. Today the light comes on again!!! I will not take this thing back to shop again. Everything seems in working order. The only thing from the list above i have not done is replace the gas cap. 04cavi
