P0421 Catalyst warm up code (Plus rant)

1889 Views 27 Replies 9 Participants Last post by Mikey319, Jul 18, 2015

Mikey319

Discussion Starter · Jul 14, 2015

Hi guys, I got a check engine light with P0421 again. For once I didn't get it for my secondary air system. However, I got an evap code (large leak) guess what? The wawa I got gas at didn't freaking put my gas cap back on and I lost it when she said we throw them out just get a new on at walmart and we'll pay you for it. I yelled I can't just run to walmart and get a new one. I need to go to the dealership! If it was original when I got gas with you it needs to be an original volkswagen replacement since it is your companies fault. Then she said well let me go check to see if we have it. Guess what? THEY DID. I wrote to the district and explained the whole thing to them and they were very apologetic and said we will handle the rudeness and train that team better. now back to the code... sorry for the rant lol. What could still be causing it? I have 2-3 more vacuum lines to replace and that's it with that, so I don't understand why it keeps doing that. It was intermittent when John tested my car with his vagcom. and lately, it's been getting stuck when the car has been sitting off at 3.6 mpg average for the (1) window in my trip computer and then I reset it and it averages normally again, or sometimes it will fix itself after a few minutes. it's very strange.

I am getting on long trips on the parkway 26.5-27.5 mpg, is that good? I have a 2002 B5.5 2.8L V6. Also, pickup has been seeming sluggish lately. I am also 400 miles over when it needed an oil change, but it is getting done this week for sure.

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Emry

· #2 · Jul 15, 2015

1) Check carefully all the vac lines. If they are old there is a chance that they are cracked and leaking. So replace them.

2) Given you have a V6 the MPG you are reporting seems fair to me.

3) Do a clean up of Throttle body, replace the air filter, use new NGK sparkplugs, replace a clogged fuel filter, to somewhat remedy the sluggishness.

Mikey319

Discussion Starter · #3 · Jul 15, 2015

Emry said:
1) Check carefully all the vac lines. If they are old there is a chance that they are cracked and leaking. So replace them.

2) Given you have a V6 the MPG you are reporting seems fair to me.

3) Do a clean up of Throttle body, replace the air filter, use new NGK sparkplugs, replace a clogged fuel filter, to somewhat remedy the sluggishness.

All but the two or so we're changed. And are going to be getting changed soon

Okay cool.

I did an alignment but not a cleaning. All of what was mentioned above has been done within the past 5.5 thousand miles. Idk what spark plugs were used though. I got the car with 81,550 miles and maintenance was done at 80,000k miles (spark plugs anyway) and the other stuff around 82-84 thousand miles.

gigi123

· #4 · Jul 15, 2015

P0421 is a code for cat below efficiency. I don't think there is an easy cure for this, other than a new cat. Your cat is at the limit of failing, that is the reason sometimes it passes, sometimes it will fail. V6 had some software update for the ECM, some reported good results using spacers. But, bottom line, P0421 reports that sometimes your cat falls below the minimum limit.

I didn't know they still have places in USA where other people still pump gas for you

Reactions: 2

sirwired

· #5 · Jul 15, 2015

gigi123 said:
I didn't know they still have places in USA where other people still pump gas for you

In NJ and OR, self-service gas is illegal.

Emry

· #6 · Jul 15, 2015

sirwired said:
In NJ and OR, self-service gas is illegal.

Actually NJ was changing their law to remove the ban. Don't know what happened to it. I think their governor had promised to introduce a bill.

zak99B5

· #7 · Jul 15, 2015

Emry said:
Actually NJ was changing their law to remove the ban. Don't know what happened to it. I think their governor had promised to introduce a bill.

I grew up in Jersey and pumped gas all through high school and into college during summers in the 80s. Great job. Especially for a kid into cars.

Mikey319

Discussion Starter · #8 · Jul 15, 2015

gigi123 said:
P0421 is a code for cat below efficiency. I don't think there is an easy cure for this, other than a new cat. Your cat is at the limit of failing, that is the reason sometimes it passes, sometimes it will fail. V6 had some software update for the ECM, some reported good results using spacers. But, bottom line, P0421 reports that sometimes your cat falls below the minimum limit.

I didn't know they still have places in USA where other people still pump gas for you

i guess I'll have to get anew cat when this one fails completely or if I don't pass inspection. Thankfully It doesn't need to be inspected until 2016.

Yes, in NJ it is illegal to pump your own gas. "We don't pump our gas we pump our fist." Oh god that quote is so stupid hahahaha I can't believe someone actually came up with that.

Reactions: 1

PZ

· #9 · Jul 15, 2015

I pumped my own gas in NJ. It helped that I worked at the gas station

Emry

· #10 · Jul 15, 2015

PZ said:
I pumped my own gas in NJ. It helped that I worked at the gas station

But you still can be charged with a criminal act against State of NJ. You are lucky that there is no extradition treaty between NJ and TX. :lol:

oke:

sirwired

· #11 · Jul 15, 2015

Having to replace the cat when it posts a CEL isn't as bad as it sounds. Since you don't live in CA, there are plenty of aftermarket cats available that will work just fine.

Reactions: 1

Tomvw

· #12 · Jul 16, 2015

sirwired said:
Having to replace the cat when it posts a CEL isn't as bad as it sounds. Since you don't live in CA, there are plenty of aftermarket cats available that will work just fine.

Why is CA excluded ?

scotts13

· #13 · Jul 16, 2015

Tomvw said:
Why is CA excluded ?

California has special emissions regulations not present in the other 49 states. In this case, a replacement CAT must bear a special California-certified label, and can only be installed by a specially certified technician. Plus, they actually check all that, at each yearly inspection. Very few aftermarket companies (possibly none?) produce CA CATs, and used ones are also forbidden.

Reactions: 1

Emry

· #14 · Jul 16, 2015

scotts13 said:
California has special emissions regulations not present in the other 49 states. In this case, a replacement CAT must bear a special California-certified label, and can only be installed by a specially certified technician. Plus, they actually check all that, at each yearly inspection. Very few aftermarket companies (possibly none?) produce CA CATs, and used ones are also forbidden.

Then why would someone possibly want to live in CA?

gigi123

· #15 · Jul 16, 2015

Weather is nice all around year, you can go swimming and skying within driving distance, very nice scenery all around, beautiful places to visit, very enjoyable outdoor activities 12 months a year pretty much, and maybe even more

I hope all CA people are scared of catalytic converters and leave CA...

Mikey319

Discussion Starter · #16 · Jul 17, 2015

I got the code again. I deleted it again and I'll see if it comes back tomorrow. Could my system just need a reflash possibly? How much would replacing the cats cost, roughly? I am getting a 1,000-2,000 dollar check from dad soon. I also don't really want to put much more into this car. I bought it for 5 thousand in March and now it has been about 3,200 dollars worth of work it has needed and still needs more.

Mikey319

Discussion Starter · #17 · Jul 17, 2015

And that noise I have been hearing over bumps and occasioanl turning is I think my control arm. Could it just be loose or does it need to be replaced do you think?

sirwired

· #18 · Jul 17, 2015

RockAuto has replacement direct-fit cats for under $300. Any exhaust shop can do the work pretty cheaply.

Reactions: 1

scotts13

· #19 · Jul 17, 2015

Mikey319 said:
And that noise I have been hearing over bumps and occasioanl turning is I think my control arm. Could it just be loose or does it need to be replaced do you think?

I've never heard of a control arm that "just needed to be tightened up." 80-90 thousand miles is a little early, but if they're rattling or clunking, it's time to get out and get under. If the bushings are worn, it should be pretty obvious. Then you replace them.

Reactions: 1

PZ

· #20 · Jul 17, 2015

Emry said:
Then why would someone possibly want to live in CA?

Because it's far from Detroit ?

:lol:

Reactions: 1

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