P0104 Error On 2004 Ls430

[curiousB]

Driving today my dash lit up on me. CEL went on, TRAC Off lit up, ! sign lit up, and the Check VSC was displayed in the info window (see photo below).

Using OBD reader found error code P0104 in log. Seems to relate to MAF. Anyway its been a strange couple days of weather here so wondering if its just a weather induced intermittent. I cleared the code and will wait to see if it returns. Car seems to run fine. I don't notice any hesistation.

Wondering if anyone else has had this error and if it points to bigger troubles down the road?

[steve2006]

As you correctly say it points to the MAF or an induction leak between the MAF and intake so check everyting is tight, time will tell if the lights return.

[curiousB]

Popped another code today. P0430. Reset CEL and went for a drive. 50-60 miles and it didn't return.

So now have P0104 and P0430 in last 24 hours. Anyone seen this? I assume they are related. Perhaps MAF malfunctioning led to rich fuel so the CATs couldn't do their job. Just guessing.

[landar]

I have seen similar strange behavior when the battery or alt are on the way out.

[curiousB]

OK the plot thickens.

Popped another code yesterday. This time another P0430. So in sequence: P0104, a day later P0430 then 3 days later another P0430.

So this is making me feel it is less to do with the MAF and more an O2 sensor problem or leaky exhaust pipe or the CAT gasket....

I did read somewhere that O2 sensor can get carboned up after a 100k or so miles so maybe mine isn't putting out a valid signal anymore.

[landar]

OK the plot thickens.

Popped another code yesterday. This time another P0430. So in sequence: P0104, a day later P0430 then 3 days later another P0430.

So this is making me feel it is less to do with the MAF and more an O2 sensor problem or leaky exhaust pipe or the CAT gasket....

I did read somewhere that O2 sensor can get carboned up after a 100k or so miles so maybe mine isn't putting out a valid signal anymore.

I realize that you may not like this advice so take it with a grain of salt... would you try a couple of tanks of premium fuel from a top tier supplier and see if you notice any difference?

[curiousB]

Just filled up with premium from a high volume place. Tank was near empty so no real mixing of old with new. See if that changes anything. I did pop another P0430 shortly after the fill up but so soon after its hard to say if it was related.

Got the car up on ramps to snoop around. Found a very slight leak at the flange on the output side of the right CAT. I've read leaks can trigger P0430 errors so this may be something. It’s very slight. I can't quite sort out in my mind how a slight loss of exhaust volume through a pinhole would change the O2 level much.

Since the downstream O2 sensors are both the same I swapped the left with the right and vice versa. If it’s a sensor problem then the problem should migrate over to the other bank. If the code pops on the same bank as before it’s either the leak at the flange or maybe my CAT is done. Hopefully not the CAT as they are $1000+....

I though the tough part of the O2 sensor would be getting it undone from the exhaust pipe. This was actually pretty easy. Lexus in their brilliance decided to put the CAT connectors inside the cabin presumably so they wouldn’t get all the road grime to corrode the pins. We that may have been a good idea but it was a royal pain to get enough disassembled to get to the connector and free up the cable. Another case of progressive assembly where you have to undo some many things to get to the one item you need (starter motor, water pump, …). To me that’s poor engineering. For all the great things they engineer in these cars serviceability isn’t one of them.

[DEATH_AWAITS_YOU]

Driving today my dash lit up on me. CEL went on, TRAC Off lit up, ! sign lit up, and the Check VSC was displayed in the info window (see photo below).

Using OBD reader found error code P0104 in log. Seems to relate to MAF. Anyway its been a strange couple days of weather here so wondering if its just a weather induced intermittent. I cleared the code and will wait to see if it returns. Car seems to run fine. I don't notice any hesistation.

Wondering if anyone else has had this error and if it points to bigger troubles down the road?

You need a Bank2 (passenger side) catalytic converter. Stop swapping parts, you're wasting time. I've seen it a hundred times.

[curiousB]

You need a Bank2 (passenger side) catalytic converter. Stop swapping parts, you're wasting time. I've seen it a hundred times.

That could be but for $1000+ for the converter I think I'll exhaust the $9 CAT gasket and the $70 O2 sensor first. So far it has cost me $0. Just some of my time. If the error code flips over to the left side then I know its the O2 sensor. If I get a repeat error code on the right side I'll spring for the CAT gasket. If after the gasket I get an error code I'll have to cave in for the CAT.

I plan to be around quite a while before I meet up with death so a bit of extra effort won't hurt any.

[landar]

Sounds like a good, methodical plan, curiousB. Keep us informed as to what you find.

[DEATH_AWAITS_YOU]

I don't have the luxury of "trying" different things to see what works. I have to be right the first time and, I now know I am also correct. Check aftermarket suppliers for a replacement cat/conv($400-$600). I used one on the last one I did a couple of weeks ago and it worked pretty well. Not as efficient as OE when watching on data stream, but enough to keep the light off and work.

[curiousB]

OK popped another code today. P0430.

So problem didn't move to other side with the swapped O2 sensors. So narrows it down to catalytic converter or the leak.

Its either going to cost $15 or $1000+. I don't like where this is trending.

[curiousB]

OK so got a new gasket for CAT to exhaust pipe and installed it. Kind of a pain working with ramps. Here's where a lift would be nice.

I think it fixed the slight leak at the flange I had but I'm not too hopeful this fixes my P0430 problem. I did look at OBDII signals for O2 sensors and the bank 2 secondary O2 waveform is not as stable as the signal on the bank 1 side. I've read that points to a catalytic converter which has lost its O2 storing capability (i.e. worn out). Starting to look like a CAT converter.

I did see the primary O2 sensor on bank 2 was about half the crossings as the bank 1. Wondering if a lazy O2 ahead of the catalytic converter is compounding my woes.

I'll post a screen shot tomorrow comparing the waveforms.

Lexus sells the converters for $1100 each.. Ouch... Anyone used the ones below? At $150/each it seems too good to be true.

http://cgi.ebay.com/ebaymotors/2004-2005-2006-LEXUS-LS430-CATALYTIC-CONVERTER-PS-51873-_W0QQcmdZViewItemQQfitsZModelQ3aLS430Q7cMakeQ3aLexusQQhashZitem3a6207b1c8QQitemZ250752774600QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[jaswood]

OK so got a new gasket for CAT to exhaust pipe and installed it. Kind of a pain working with ramps. Here's where a lift would be nice.

I think it fixed the slight leak at the flange I had but I'm not too hopeful this fixes my P0430 problem. I did look at OBDII signals for O2 sensors and the bank 2 secondary O2 waveform is not as stable as the signal on the bank 1 side. I've read that points to a catalytic converter which has lost its O2 storing capability (i.e. worn out). Starting to look like a CAT converter.

I did see the primary O2 sensor on bank 2 was about half the crossings as the bank 1. Wondering if a lazy O2 ahead of the catalytic converter is compounding my woes.

I'll post a screen shot tomorrow comparing the waveforms.

Lexus sells the converters for $1100 each.. Ouch... Anyone used the ones below? At $150/each it seems too good to be true.

Yes, I've had 2 "non-california" ones on my '95 for a number of years now.

http://cgi.ebay.com/ebaymotors/2004-2005-2006-LEXUS-LS430-CATALYTIC-CONVERTER-PS-51873-_W0QQcmdZViewItemQQfitsZModelQ3aLS430Q7cMakeQ3aLexusQQhashZitem3a6207b1c8QQitemZ250752774600QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[curiousB]

OK looks like my Bank 2 Catalytic converter is done. Unfortunately highest cost scenario.

I fixed the post catalytic converter flange leak with a new crush gasket but I got an error again today CEL, VSC, ... !error and P0430 in error log.

I went for a drive and logged the attached O2 sensors graphs which tell part of the story.

Am I missing anything here? I am out of ideas other than to plunk a big chunk of $$ down for a new catalytic converter.

I'm at 105,500 miles so I guess everything has a service life. Just wondering if I should do new O2 sensors while I'm at it. This could get pricey.

Any good sources for low cost direct fit catalytic converters?

Lexus O2 Readings.pdf

[landar]

There is also some talk on various sites about consistently using a fuel octane lower than what is recommended for the vehicle. There is mention of the timing being retarded by the computer resulting in a richer fuel air mixture and premature fouling of the cats. Some poo-poo the notion, others say it clearly shortens the life.

Then of course, theres the "snake oil" route :whistles: http://www.amazon.com/Cataclean-Engine-Catalytic-Converter-Treatment/dp/B002BVXM92

[curiousB]

Then of course, theres the "snake oil" route :whistles: http://www.amazon.com/Cataclean-Engine-Catalytic-Converter-Treatment/dp/B002BVXM92

I've grown tired of the warning lights on the dash so I ordered a Catalytic converter on eBay and a new Oxygen sensor for ahead of the converter in question (bank 2). I read that a lazy O2 sensor can lead to premature catalytic converter failure. For the sake of an extra $70 I thought better to put the new on in while I have the converter out and the O2 is easier to get at.

We'll see if my $175 catalytic converter performs. I wasn't too keen to buy the $1000+ Lexus version. I guess if the cheaper one doesn't work I've wasted $175 but for a 5X cost reduction it seemed worth the wager.

[DEATH_AWAITS_YOU]

"You need a Bank2 (passenger side) catalytic converter. Stop swapping parts, you're wasting time. I've seen it a hundred times. I don't have the luxury of "trying" different things to see what works. I have to be right the first time and, I now know I am also correct. Check aftermarket suppliers for a replacement cat/conv($400-$600). I used one on the last one I did a couple of weeks ago and it worked pretty well. Not as efficient as OE when watching on data stream, but enough to keep the light off and work." Sound familiar?

[curiousB]

...Sound familiar?

Yes D.A.Y. (sounds less gruesome than your silly moniker). I will replace the converter as you suggested.

I don’t regret a bit of what I have tried. I do this as a hobby not as a profession. So learning is a principal objective of mine. The reason I’ve gone to the trouble to document my steps is in hopes it helps the next guy who has this same problem. With a lot of LS430’s coming up on 100k miles this problem will likely become more frequent.

Through this I’ve spent some time and $10 on a gasket I might not be able to reuse. In return I got to dig into my OBDII software that I hadn’t used much yet. I also read a lot about O2 sensors and catalytic converters. It’s been a worthwhile exercise in my book.

Since you seem knowledgeable how about looking at the PDF I uploaded a few days ago and see if those O2 sensor outputs bank 1 and bank 2 and see if they are similar to what you’ve seen. Since I only own one Lexus (and only work on mine) I don’t have the benefit of seeing across multiple vehicles.

[landar]

That graph of bank 1 vs 2 implies that something unusual is going on ahead of the converter. If the first sensor is bad or marginal then that could explain it. Or perhaps your combustion is compromised somehow. I think I accidentally deleted my post suggesting new spark plugs. You are coming due for new ones so it would not be a bad idea to change them if you have not already done so.

I am surprised though as 100k on cats is not the norm. At least not from what I have heard. More in the 150-200k range.

[curiousB]

Yes I'm due for plugs so its a good idea to change then anyway. Hopefully I can gently pull off the coil over plug without breaking them. They've been undisturbed since original install in 2003....

I've read O2 sensors (4 wire OBDII type) have a service life of 100k miles. Symptoms of a failing sensor is they get sluggish and don't cycle back and forth as fast as they did. I presume due to contamination of the substrate from years of baking at 600+ degrees. In my case the bank 2 O2 sensor is about half as active as the bank 1 sensor suggesting it is starting to fail. Maybe that contributed to premature CAT failure.

So I've ordered the parts and will attack this in a couple week. The O2 sensor (ahead of CAT) on the Bank 2 is easier to get at with the CAT off so I'll just put a new one in as good measure.

Gas mileage is still very good so I don't think there is major ignition or fuel problems.

I saw this voodoo solution on Utube.. Wonder if its a real solution or witchcraft....

[landar]

Well, if cleaning is voodoo then yes. It does make a certain amount of sense but does presume the cat does not work because it is simply dirty. It might be failing for other reasons. However, I think it is worth a shot (cleaning that is).

Now you mention that perhaps the O2 sensor partially failed and that may have contributed to the cat failure. Yet you do not think that anything was wrong with the combustion mixture because mileage had not suffered. I have to ask, how would a failing O2 sensor contribute to cat failure if not via fuel mixture? Is there another variable in the mix that I am missing?

BTW, you are now a "Guru" member curiousB. Congrats!

[curiousB]

Well not sure I truly qualify as a Guru. That would imply I actually know something......

You make a good point about the O2 sensor and fuel mix. I really don't see a MPG decline. In fact the car is actually getting better with age... I am really not too sure why the converter catalyst is failed (and not 100% sure it has). I did see somewhere the lazy O2 ahead of Catalyst means longer excursions of too lean then too rich. On average about the same as a faster cycling O2 but perhaps the rich cycles do more harm (overheat the catalyst) than the lean cycles. Another theory is the P0420/P0420 error code is determined by the difference between the pre and post catalyst O2 waveforms over time. I guess if the presignal is a little off (not cycling enough) that might undermine the algorithm as much as the trailing signal. Hard to say as they don’t publish the algorithms. I have been burning regular fuel for a couple years and maybe that is a contributing factor as well.

All the parts have arrived so once we get a day below 100+ degrees I'll give it a go. Just a little concerned the three bolts on the top end of the converter. They look hard to get at and maybe rusted in pretty good. Crawling under ramps doesn’t make this too much fun. I could really go for a lift....

For a laugh I'll throw the old converter in soapy water and flush it out but won’t reinstall it. I’ll hang onto it in case the new low cost converter is a no go.

I notice the non-OEM catalytic converter I bought was for 49 states (hence not legal for California with their stricter emissions). That said the Lexus OEM part didn’t differentiate this detail so I wonder if Lexus just made the entire fleet California compliant rather than have differing models? Might explain why the Lexus OEM converter is $1000+. To meet California they have more rare metals deposited on the catalyst core.

[landar]

I was also thinking that if the cat could be cleaned, would there not be a lot more garages that could do a professional job of it? Yet I never hear of that. The general consensus of mechanics is that you just install a new one. Not their money.

I wonder also if the use of lower octane gas would cause a tug-of-war with fuel mixture between a failing pre-cat sensor and retarded timing. Guess it would depend upon engine loads too.

I have heard Lexus mechanics say that non-OEM converters will not last very long if indeed they work at all. The cost probably depends a great deal upon what kind and thickness of the precious metal coated onto the ceramic honeycomb. I would get back on the higher octane fuel and hope that the other cat does not go soon and that the replacement holds up for a reasonable amount of time.

Good learning experience though. I have to say, I think you are a Guru of sorts. You sure are a curious learner and tenaciously dig into the details. And as a result, we all benefit.

[curiousB]

Back from vacation and parts are in. Catalytic converter, O2 sensor, gaskets.

Got front of car up on ramps and removed all the covers to get ready for the work. Did I say how nice a lift would be already. Costco has this portable two post lift on sale right now..( http://www.costco.com/Browse/Product.aspx?Prodid=11589445&whse=BC&Ne=4000000&eCat=BC|3960|21277|61837&N=4018446&Mo=2&pos=5&No=0&Nr=P_CatalogName:BC&cat=61837&Ns=P_Price|1||P_SignDesc1〈=en-US&Sp=C&ec=BC-EC22577-Cat21277&topnav= ) for $1900. Wonder how safe it is though.

Decided I didn't have enough time to do it tonight all so I just changed the Bank 2 primary O2 sensor today. Will try the catalytic converter on the weekend.

Went for a drive to see if the new sensor changed my lazy sensor theory any. Plugged in OBDII module and laptop. Had graphs of O2 primaries against each other. Some difference from before, the new O2 sensor seem a bit more active but still not as much as the bank 1 primary O2. Anyway I reset the P0430 error code and will see if I pop another P0430 by the weekend. I am not too hopeful the primary O2 will fix things because the post converter O2 on bank 2 is still much more active than bank 1 suggesting the catalyst isn't doing its job.

The replacement converter looks pretty good. Slightly different design from OEM. Has flange seams down the sides where they weld the two halves together. The mounting flanges look OK but the drilled holes look pretty large. I may need washers for the bolts so then don't bind in the holes. The catalyst looks clean and quite the beehive of passages. No way to tell by looking if it is a robust as OEM. I guess we'll see.