p0420 and p0430... Do I need new Cats?
07-18-16, 07:58 PM
#1
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
p0420 and p0430... Do I need new Cats?
Hello I have a 2001 GS430, 190k miles. Im getting the check engine light po420 and p0430. The car drives fine with no problems. The onboard computer says I average out 17.5 mpg, and theres sometimes a gas smell coming from somewhere under the car or exhaust. Its all stock. I need to smog the car so I can register it, I recently bought it so I dont know its past.
07-19-16, 12:15 AM
#2
Check the gaskets before and after the cats for leaks first. This is the most common cause of that code, followed by O2 sensors, and then bad cats. Try to eliminate the least expensive potential causes first before you spend a whole bunch of money replacing the cats as they rarely go bad on these cars.
07-19-16, 01:04 AM
#3
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Check the gaskets before and after the cats for leaks first. This is the most common cause of that code, followed by O2 sensors, and then bad cats. Try to eliminate the least expensive potential causes first before you spend a whole bunch of money replacing the cats as they rarely go bad on these cars.
07-19-16, 05:37 AM
#4
Check the gaskets before and after the cats for leaks first. This is the most common cause of that code, followed by O2 sensors, and then bad cats. Try to eliminate the least expensive potential causes first before you spend a whole bunch of money replacing the cats as they rarely go bad on these cars.
i had a leak at that flange... so i replaced the gasket... but then still had the code... my mechanic took off the heat shields on the y-pipe... there were more holes there before the 3rd cat and i ended up having to replace the y-pipe...
you can see if you O2 sensors are bad thru an OBD2 reader... try everything else before even thinking about replacing the cats... they are expensive... and those that have changed them still had an issue...
BTW - search, there are plenty of threads that have discussed this topic already...
07-19-16, 03:28 PM
#5
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
i have the same exact car as you and had this pop up last year before my emissions inspection as well... check for leaks, that is 80% the issue... at the flange after the cat on the exhaust manifold bolts to the y-pipe, see if there are leaks... you can mix soapy water into a spray bottle... and with the car running, spray it on the flange... if there is a leak, you will see bubbles form... you can also have someone cover the tailpipe with a rag and listen for leaks there...
i had a leak at that flange... so i replaced the gasket... but then still had the code... my mechanic took off the heat shields on the y-pipe... there were more holes there before the 3rd cat and i ended up having to replace the y-pipe...
you can see if you O2 sensors are bad thru an OBD2 reader... try everything else before even thinking about replacing the cats... they are expensive... and those that have changed them still had an issue...
BTW - search, there are plenty of threads that have discussed this topic already...
i had a leak at that flange... so i replaced the gasket... but then still had the code... my mechanic took off the heat shields on the y-pipe... there were more holes there before the 3rd cat and i ended up having to replace the y-pipe...
you can see if you O2 sensors are bad thru an OBD2 reader... try everything else before even thinking about replacing the cats... they are expensive... and those that have changed them still had an issue...
BTW - search, there are plenty of threads that have discussed this topic already...
07-19-16, 04:54 PM
#6
i have the same exact car as you and had this pop up last year before my emissions inspection as well... check for leaks, that is 80% the issue... at the flange after the cat on the exhaust manifold bolts to the y-pipe, see if there are leaks... you can mix soapy water into a spray bottle... and with the car running, spray it on the flange... if there is a leak, you will see bubbles form... you can also have someone cover the tailpipe with a rag and listen for leaks there...
i had a leak at that flange... so i replaced the gasket... but then still had the code... my mechanic took off the heat shields on the y-pipe... there were more holes there before the 3rd cat and i ended up having to replace the y-pipe...
you can see if you O2 sensors are bad thru an OBD2 reader... try everything else before even thinking about replacing the cats... they are expensive... and those that have changed them still had an issue...
BTW - search, there are plenty of threads that have discussed this topic already...
i had a leak at that flange... so i replaced the gasket... but then still had the code... my mechanic took off the heat shields on the y-pipe... there were more holes there before the 3rd cat and i ended up having to replace the y-pipe...
you can see if you O2 sensors are bad thru an OBD2 reader... try everything else before even thinking about replacing the cats... they are expensive... and those that have changed them still had an issue...
BTW - search, there are plenty of threads that have discussed this topic already...
Trending Topics
07-19-16, 05:25 PM
#8
Lexus Champion
Are you smelling any consistent sulpher smell during driving? Not an intermittent one but a constant smell? Next step, get a live scan on an obdII reader and see what the readings tell you.
I went through this three years ago and yes it was in fact a cat. It happens on these cars believe it or not. The previous owner had run this car hard on a trip through Montana and wanted to check out its high speed capabilities. Turns out he may have cooked a cat - so I replaced both cats and have not had a problem since.
I went through this three years ago and yes it was in fact a cat. It happens on these cars believe it or not. The previous owner had run this car hard on a trip through Montana and wanted to check out its high speed capabilities. Turns out he may have cooked a cat - so I replaced both cats and have not had a problem since.
07-19-16, 05:27 PM
#9
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Are you smelling any consistent sulpher smell during driving? Not an intermittent one but a constant smell? Next step, get a live scan on an obdII reader and see what the readings tell you.
I went through this three years ago and yes it was in fact a cat. It happens on these cars believe it or not. The previous owner had run this car hard on a trip through Montana and wanted to check out its high speed capabilities. Turns out he may have cooked a cat - so I replaced both cats and have not had a problem since.
I went through this three years ago and yes it was in fact a cat. It happens on these cars believe it or not. The previous owner had run this car hard on a trip through Montana and wanted to check out its high speed capabilities. Turns out he may have cooked a cat - so I replaced both cats and have not had a problem since.
07-20-16, 06:17 PM
#10
Lexus Champion
Originally Posted by Muayad925
no i dont but i smell gas fumes every now and then, i will buy a live scanner ob2 from amazon and go from there
I know I tended to have a consistent sulpher smell on my car so it had me worried and I should have dealt with it better than I did. You go to an exhaust shop and they'll tell you that you're going to cook your expensive motor because you've got a plugged cat and it will destroy your car.
Right now, you have a code and that's about it. If the car is running fine and not overheating you'll be ok for a while until you can figure it out.
On the obdii scanner, you're looking for fuel trim issues to see if you have an o2 sensor issue. These are the cheaper fixes rather than heading over to a cat replacement. Good luck with it.
07-20-16, 07:23 PM
#11
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Ok. That's a good sign in a strange way. You may have an issue with the charcoal canister instead. Gasoline fumes are another category of problem. Could be something very minor or just an indication that the canister needs replacing.
I know I tended to have a consistent sulpher smell on my car so it had me worried and I should have dealt with it better than I did. You go to an exhaust shop and they'll tell you that you're going to cook your expensive motor because you've got a plugged cat and it will destroy your car.
Right now, you have a code and that's about it. If the car is running fine and not overheating you'll be ok for a while until you can figure it out.
On the obdii scanner, you're looking for fuel trim issues to see if you have an o2 sensor issue. These are the cheaper fixes rather than heading over to a cat replacement. Good luck with it.
I know I tended to have a consistent sulpher smell on my car so it had me worried and I should have dealt with it better than I did. You go to an exhaust shop and they'll tell you that you're going to cook your expensive motor because you've got a plugged cat and it will destroy your car.
Right now, you have a code and that's about it. If the car is running fine and not overheating you'll be ok for a while until you can figure it out.
On the obdii scanner, you're looking for fuel trim issues to see if you have an o2 sensor issue. These are the cheaper fixes rather than heading over to a cat replacement. Good luck with it.
So while driving it I was constantly checking the "I/M" tab of it seeing if all the moniters would be ready so I might have a chance to smog it. So when the oxygen sensor monitors went from not ready to ready, the p0420 and p0430 code came on as pending. Right when I hit 20 miles, The cat monitor became ready and threw the engine light. The evap monitor was still at "Not Ready" I dont know if this might hint at anything but i just thought ill share it
07-22-16, 01:19 PM
#12
Driver School Candidate
Join Date: Sep 2011
Location: NJ
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
im having the same problem with the p0430 code, didn't see any exhaust leaks so took it to the shop, swapped the cat code came back, exhaust shop swapped it again at no cost and came back again, swapped the bank 2 sensor 2 and waiting to see if it comes back. Looking at the readings for the O2 sensor im going to say it will be back. Hopefully you don't waste the money I have. lol
07-22-16, 01:41 PM
#13
Hello I have a 2001 GS430, 190k miles. Im getting the check engine light po420 and p0430. The car drives fine with no problems. The onboard computer says I average out 17.5 mpg, and theres sometimes a gas smell coming from somewhere under the car or exhaust. Its all stock. I need to smog the car so I can register it, I recently bought it so I dont know its past.
per CA DMV website:
Smog Certification:If the vehicle is over 4 years old, it is the seller's responsibility to provide proof of a current smog certification unless the a smog certification was submitted within the past 90 days. Proof of smog certification is not required if the title to the vehicle is being transferred within a family. If you do sell it without a smog certification and it doesn't pass, the seller is responsible for repairing it to the smog certification standards.
07-23-16, 12:39 PM
#14
Driver School Candidate
Thread Starter
Join Date: Jul 2016
Location: CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Hey if you bought the car in CA you should seriously consider having the seller work something out with you. In CA its the sellers burden to smog the car before re-sale. Basically from what I was told CA got tired of a people buying cars they couldn't register.. I believe this rule even applies if the car is sold as-is. The only exception to this rule is if the buyer agrees and signs a contract saying that he is buying the car for parts only. I believe you can also fix the issue yourself and bill the seller for your time / cost of parts.
per CA DMV website:
Smog Certification:If the vehicle is over 4 years old, it is the seller's responsibility to provide proof of a current smog certification unless the a smog certification was submitted within the past 90 days. Proof of smog certification is not required if the title to the vehicle is being transferred within a family. If you do sell it without a smog certification and it doesn't pass, the seller is responsible for repairing it to the smog certification standards.
per CA DMV website:
Smog Certification:If the vehicle is over 4 years old, it is the seller's responsibility to provide proof of a current smog certification unless the a smog certification was submitted within the past 90 days. Proof of smog certification is not required if the title to the vehicle is being transferred within a family. If you do sell it without a smog certification and it doesn't pass, the seller is responsible for repairing it to the smog certification standards.
I ran some scannings with the 02 sensors, hopefully someone can help me understand them.
While idle.
https://youtu.be/PUNi3ciscZc
While revving
https://youtu.be/h8WLv1_7eNQ
021s2 stays below .055
021s1 and 021s2 fall to .0 after revving
Thread
Thread Starter
Forum
Replies
Last Post