Catalyst Converter Carbon Build Up Issue
05-15-14, 04:32 PM
#1
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Thread Starter
Catalyst Converter Carbon Build Up Issue
I've had the carbon build up work completed on my IS250 but the P0420 code keeps turning on and off. I've replace the gas cap, the air fuel sensors, and have had the cats cleaned but the code keeps coming on.
Catalyst converters work by acting as a catalyst (hence the name) for a chemical reaction to break hydrocarbons (ie. gas) into carbon dioxide and other less polluting compounds. This reaction reduces heat. When a vehicle is running rich (too much gas) or misfires letting burnt gas into the exhaust, the cat needs to work harder, making more heat. Too much heat and the catalyst (which is honycombed to make more surface area to react with the exhaust) can melt- hence: dead converter and air fuel sensors.
The IS250 and the GS300 have had a lot of misfire issues but Lexus is skirting around the issue where they are saying that the carbon build up did not cause the cats or the sensors to go bad. In reality it would cost them more to replace the sensors and the cat converters than to replace the pistons and other components.
Please call corporate and voice your concerns so Lexus will take action. I've seen countless posts where people have said that Lexus Techs have been instructed to mislead customers.
1-800-255-3987
Catalyst converters work by acting as a catalyst (hence the name) for a chemical reaction to break hydrocarbons (ie. gas) into carbon dioxide and other less polluting compounds. This reaction reduces heat. When a vehicle is running rich (too much gas) or misfires letting burnt gas into the exhaust, the cat needs to work harder, making more heat. Too much heat and the catalyst (which is honycombed to make more surface area to react with the exhaust) can melt- hence: dead converter and air fuel sensors.
The IS250 and the GS300 have had a lot of misfire issues but Lexus is skirting around the issue where they are saying that the carbon build up did not cause the cats or the sensors to go bad. In reality it would cost them more to replace the sensors and the cat converters than to replace the pistons and other components.
Please call corporate and voice your concerns so Lexus will take action. I've seen countless posts where people have said that Lexus Techs have been instructed to mislead customers.
1-800-255-3987
05-15-14, 05:11 PM
#3
The IS250 and the GS300 have had a lot of misfire issues but Lexus is skirting around the issue where they are saying that the carbon build up did not cause the cats or the sensors to go bad. In reality it would cost them more to replace the sensors and the cat converters than to replace the pistons and other components.
Please call corporate and voice your concerns so Lexus will take action. I've seen countless posts where people have said that Lexus Techs have been instructed to mislead customers.
1-800-255-3987
Please call corporate and voice your concerns so Lexus will take action. I've seen countless posts where people have said that Lexus Techs have been instructed to mislead customers.
1-800-255-3987
These newer cars are pretty smart. When excessive misfiring takes place, it will shut down fuel to that cylinder to avoid damaging the cat. It takes a lot to kill a cat.
Id love to see posts where Lexus techs were instructed to mislead their customers.............
05-15-14, 05:22 PM
#4
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Quote:
Originally Posted by jetson23 View Post
Hello all. First post here. I apologize as I'm sure these questions have been asked, but I recently discovered this board and not sure I'm up for searching through 60+ pages of posts on the subject. I have the rough idle issue, but unfortunately have not been able to get it fixed, so I'm wondering if I have any course of action.
The issue first started in December of 2011. What happened was, I was making a turn at a light, hit the gas to accelerate and the engine started to rumble and sputter, the check engine light came on, and the display showed "Check VSC"(or something like that), and I couldn't go faster than about 30 mph. Got the care home and shut it off, made an appointment at my Lexus dealership for the next day. The next day I brought it in and it ran fine. They did some diagnostics and said something about carbon buildup in the engine that they cleaned out, and added something to my gas tank.
The second time was in December of 2012, and pretty much the exact same symptoms occurred. I shut the car off for a few minutes, restarted it, and drove straight to the dealership. This was not long before the CSP came out about the rough idle issue. I got the letter a week or two after the dealership again checked it out, and called my dealership to ask them about it. They claimed they were doing the testing for the issue, trying to reproduce it. But I was told that since they could not reproduce the issue there, they would not be authorized by Lexus to do the repairs.
Before December of 2011, I had definitely noticed the rough idle when coming to a stop now and then. I have noticed it since then as well. Not often, but it does happen.
I kept thinking I would see the issue again, and the dealership would be able to reproduce it, but that has never happened. However, I have also been reading stuff on here and elsewhere that the reproducing thing isn't necessarily true, and if I have enough of the misfire codes, the dealership should do the repair. So, I have a few questions.
1. Will the misfire codes from the last several years still show up when a tech looks at the vehicle?
2. Should this be enough for the dealership to do the repairs?
3. My dealership is Lexus of Wayzata (Minnesota). Has anyone had this issue repaired there?
4. Is it worth it to find another dealership somewhat nearby to take it to if they have fixed the issue by just finding the misfire codes in the diagnostics?
Thanks in advance for any help.
1. Will the misfire codes from the last several years still show up when a tech looks at the vehicle?
• The same events occurred with my 2007. The dealer said that the codes were not stored in the central computer in either event. Since I could not prove the events, there was nothing they could do. I called Lexus corporate directly and received a case number and case manager. After the case manager checked with the dealer, she told me there was nothing they could do. They denied the problem along with communications that many owners had received concerning the problem. Apparently, there is a warranty repair letter concerning the problem. I never received it but received a PDF copy of it from another owner from this group.
2. Should this be enough for the dealership to do the repairs?
Many owners have written that this is enough, however others have written that it is not. My dealer (one of the largest in the Greater Philadelphia Area) told me they are not responsible for any repairs, even though my car was still under warranty and below the mileage limit.
3. My dealership is Lexus of Wayzata (Minnesota). Has anyone had this issue repaired there?
I'm in Philadelphia –*so you know not to come here for repairs.
4. Is it worth it to find another dealership somewhat nearby to take it to if they have fixed the issue by just finding the misfire codes in the diagnostics?
The Lexus techs know the codes –*one took me aside and told me he knew exactly what the problem is. I told him about the warning lights that illuminated when my car shut down and wouldn't reach 25 MPH. The signal light combination matched exactly with the carbon build-up and piston ring problem. The techs are aware of the problem but are being instructed to mislead customers. Oh, and if you haven't experienced it with your vehicle yet, you will start burning one quart of oil every 1200 miles. They told me this is normal (my car had 73,000 miles on it when it started consuming oil) –*of course, you know that burning a quart of oil every 1200 miles in NOT normal for any car.
Read more: https://www.clublexus.com/forums/is-...#ixzz31pjMSePi
Quote:
Originally Posted by jetson23 View Post
Hello all. First post here. I apologize as I'm sure these questions have been asked, but I recently discovered this board and not sure I'm up for searching through 60+ pages of posts on the subject. I have the rough idle issue, but unfortunately have not been able to get it fixed, so I'm wondering if I have any course of action.
The issue first started in December of 2011. What happened was, I was making a turn at a light, hit the gas to accelerate and the engine started to rumble and sputter, the check engine light came on, and the display showed "Check VSC"(or something like that), and I couldn't go faster than about 30 mph. Got the care home and shut it off, made an appointment at my Lexus dealership for the next day. The next day I brought it in and it ran fine. They did some diagnostics and said something about carbon buildup in the engine that they cleaned out, and added something to my gas tank.
The second time was in December of 2012, and pretty much the exact same symptoms occurred. I shut the car off for a few minutes, restarted it, and drove straight to the dealership. This was not long before the CSP came out about the rough idle issue. I got the letter a week or two after the dealership again checked it out, and called my dealership to ask them about it. They claimed they were doing the testing for the issue, trying to reproduce it. But I was told that since they could not reproduce the issue there, they would not be authorized by Lexus to do the repairs.
Before December of 2011, I had definitely noticed the rough idle when coming to a stop now and then. I have noticed it since then as well. Not often, but it does happen.
I kept thinking I would see the issue again, and the dealership would be able to reproduce it, but that has never happened. However, I have also been reading stuff on here and elsewhere that the reproducing thing isn't necessarily true, and if I have enough of the misfire codes, the dealership should do the repair. So, I have a few questions.
1. Will the misfire codes from the last several years still show up when a tech looks at the vehicle?
2. Should this be enough for the dealership to do the repairs?
3. My dealership is Lexus of Wayzata (Minnesota). Has anyone had this issue repaired there?
4. Is it worth it to find another dealership somewhat nearby to take it to if they have fixed the issue by just finding the misfire codes in the diagnostics?
Thanks in advance for any help.
1. Will the misfire codes from the last several years still show up when a tech looks at the vehicle?
• The same events occurred with my 2007. The dealer said that the codes were not stored in the central computer in either event. Since I could not prove the events, there was nothing they could do. I called Lexus corporate directly and received a case number and case manager. After the case manager checked with the dealer, she told me there was nothing they could do. They denied the problem along with communications that many owners had received concerning the problem. Apparently, there is a warranty repair letter concerning the problem. I never received it but received a PDF copy of it from another owner from this group.
2. Should this be enough for the dealership to do the repairs?
Many owners have written that this is enough, however others have written that it is not. My dealer (one of the largest in the Greater Philadelphia Area) told me they are not responsible for any repairs, even though my car was still under warranty and below the mileage limit.
3. My dealership is Lexus of Wayzata (Minnesota). Has anyone had this issue repaired there?
I'm in Philadelphia –*so you know not to come here for repairs.
4. Is it worth it to find another dealership somewhat nearby to take it to if they have fixed the issue by just finding the misfire codes in the diagnostics?
The Lexus techs know the codes –*one took me aside and told me he knew exactly what the problem is. I told him about the warning lights that illuminated when my car shut down and wouldn't reach 25 MPH. The signal light combination matched exactly with the carbon build-up and piston ring problem. The techs are aware of the problem but are being instructed to mislead customers. Oh, and if you haven't experienced it with your vehicle yet, you will start burning one quart of oil every 1200 miles. They told me this is normal (my car had 73,000 miles on it when it started consuming oil) –*of course, you know that burning a quart of oil every 1200 miles in NOT normal for any car.
Read more: https://www.clublexus.com/forums/is-...#ixzz31pjMSePi
05-15-14, 05:25 PM
#5
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Thread Starter
I'm only bringing attention that the misfire potentially caused the sensors and the cats to go bad. You don't have to be mean about it...
Yes the newer models may have that but look at all the posts where people have had to replace sensors and cats. The misfires accelerated these parts to go bad faster.
Yes the newer models may have that but look at all the posts where people have had to replace sensors and cats. The misfires accelerated these parts to go bad faster.
05-15-14, 05:59 PM
#6
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Tajai7
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Not sure if this will help anyone but I was aware of the carbon build up issue so when I started getting a P0420 trouble code to routinely come on after 77k miles on my '06 IS250 AWD (catalyst system efficiency below threshold bank 1), it was time to take it to Lexus and argue that the carbon build up is causing the rough idling and is also damaging the cat, causing the trouble code to pop.... They wouldn't confirm that the cat was under warranty to 80k miles like I've seen in other posts, but They did acknowledge the carbon build up issue and replaced the pistons and decarbonized the cylinder heads, etc. And also replaced the failed cat as a goodwill gesture. I was very satisfied with how the dealership handled this issue, especially because it did not cost me a dime! Apparently the engine is covered under a nine year Lexus warranty. Try to take advantage of the carbon build up TSB and argue that it's damaging the cat.
Last edited by Tajai7; 10-10-12 at 08:43 PM.. Reason: Added info
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Join Date: Mar 2003
Location: Minnesota
Posts: 49
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Not sure if this will help anyone but I was aware of the carbon build up issue so when I started getting a P0420 trouble code to routinely come on after 77k miles on my '06 IS250 AWD (catalyst system efficiency below threshold bank 1), it was time to take it to Lexus and argue that the carbon build up is causing the rough idling and is also damaging the cat, causing the trouble code to pop.... They wouldn't confirm that the cat was under warranty to 80k miles like I've seen in other posts, but They did acknowledge the carbon build up issue and replaced the pistons and decarbonized the cylinder heads, etc. And also replaced the failed cat as a goodwill gesture. I was very satisfied with how the dealership handled this issue, especially because it did not cost me a dime! Apparently the engine is covered under a nine year Lexus warranty. Try to take advantage of the carbon build up TSB and argue that it's damaging the cat.
Last edited by Tajai7; 10-10-12 at 08:43 PM.. Reason: Added info
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