P0420 and P0430 - 2006 LC

[jerryb]

I read the thread again, entirely. One thing I can say now after fooling around with straight pipes, back to cat pipes, and straight pipes again is that there is something going on in the differences side to side, and I believe pressure and time. I do not think that temp has a big affect on the 420 430, I mean as long as it gets up and goes closed loop.
The prevalence of 420 should mean something, right? The fact that it's more difficult to work the cat pipe on the passenger side, messing up the stern gasket. I keep going back to cold start warm start. gas leaks, etc.

The voltage readings I'm getting are the mostly the same as everyone else here, without cats. I do have mini cat o2 extenders on there now that have their own catalyst. Still doesn't defeat it.
Either way I'm going to figure this out. Electrically or mechanically, sooner or later.
I have perfect cats sitting here to use also. I never had an emissions code before on this car.
I'm realizing now how stingy toyota is on the emission #s. Never really paid attention before as I didn't have a problem. I am now though. Because I'd really like to keep these pipes installed.

I see those voltage numbers and sort of cringe, it's so close to passing. lol.

and why, for the love of god has someone not cracked the ecu and reflashed to just mimic a narrow band output on the 4.7?
Surely there's a narrow band emulator that can do that and just plug right into the ecu on two wires?

 

[danimal24]

Borrowed a TechStream but way beyond my abilities, foreign language to me...Does anything jump right out? Still have a persistent PO420. All four sensors, new.


View attachment 2369414View attachment 2369415View attachment 2369416

Looks like your fuel trims are good on both sides....should be close to 0 and at max negative or positive 8....but close to zero is great.

Your left post cat O2 sensor (bank 1) is indicating a lean condition at the sensor...hence the P0420. The voltage should be right in the middle...or close. Like .4 to .6. low voltage means lean (air is getting in there) and high voltage means a rich condition ( more fuel than air). Since your fuel trims look good, air is getting in somewhere after the intake (e.g. exhaust system).

Looks like your right side (bank 2) is ok...voltage is close to middle

It helps to see live stream of post cat sensors to see how they are behaving. If they hold steady then you know the cat should be okay...need to find the air leak.

 

[landshark9]

Thanks @danimal24
I will try to figure out how to get the live stream. Any tips on finding the air leak?

 

[danimal24]

Two ways that come to mind:
1) on initial cold start up, look under rig for any condensation (water) leaking from connections, pipes, or fittings. I had leaks at each flange post cat and then found a pin hole in pipe connection that needs welding.

2) With live stream data running, look for an up spike in post cat voltage while artificially trying to introduce a rich conditions with propane torch un lite blowing at all connections and fittings.

Any other ideas guys?

 

[2001LC]

Have you seen any other codes recently or in last say 5K miles?

You may have a bad O2.

You may have a clogged CAT.


Other Ways to find air leak.

Look.

You can pressurize the exhaust. Then spray soap water on/at any fitting. Look for bubbles.

Rent ot find someone/shop with a good smoke machine.

Look close for carbon tails at fittings.

Drip oil and a hot exhaust at point you suspect. Oil will smoke and give visual plumes.

Being a VVT engine you have O2 threaded in. Inspect for tightness.

 

[landshark9]

All new O2's and tight. Only other code was a random MAF, replaced and hasn't come back. I'll crawl back under and see what I can see. Thanks guys!

 

[2001LC]

All new O2's and tight. Only other code was a random MAF, replaced and hasn't come back. I'll crawl back under and see what I can see. Thanks guys!

Keep checking for pending codes, as often as you can. Good luck.

 

[landshark9]

Every once in awhile I get the PO430 but only pending, never confirmed

Keep checking for pending codes, as often as you can. Good luck.

 

[2001LC]

Air leak in exhaust can do that (p0430) too.

Codes I'm most interested have to do with both P0420 & P0430 active or pending in same time frame. Or switching from side to side. If any AI codes come up, it's of a big interested to me. I'm working on a therroy now. Anyone seeing these combs, or a reoccurring CAT failure.

 

[BullElk]

Seem you could remove muffler, and not have this issue. Can't say I've tried this. But I have seen many muffler with large holes., never set off a DTC

I have found a small leak on PS of muffler. But not likely reason for code is what I’m hearing.

 

[stephen0]

Location of exhaust leak, is key, and can cause issue for sure. This is if exhaust leak before or near A/F ( forward on sensor VVT) or O2 sensors. A downstream of sensors leak, is not likely causing issue. Seem you could remove muffler, and not have this issue. Can't say I've tried this. But I have seen many muffler with large holes., never set off a DTC

Mine just started throwing a P0430. Replaced the downstream sensor. I know I have leaking manifolds. Probably best to replace those before replacing the CAT?

 

[2001LC]

Mine just started throwing a P0430. Replaced the downstream sensor. I know I have leaking manifolds. Probably best to replace those before replacing the CAT?

Upstream issues must be found, before replacing CAT, or likely goes bad again. May also find that a new CAT not needed, once upstream corrected.

Bring by if you like and I can take a look!

 

[stephen0]

Upstream issues must be found, before replacing CAT, or likely goes bad again. May also find that a new CAT not needed, once upstream corrected.

Bring by if you like and I can take a look!

I wish I could. Looks like you're in CO. I'm in Utah. Am I risking significant damage if I continue to drive it or do I need to park it until I get it resolved? Probably hard to say given the number of things it could be...

 

[2001LC]

I wish I could. Looks like you're in CO. I'm in Utah. Am I risking significant damage if I continue to drive it or do I need to park it until I get it resolved? Probably hard to say given the number of things it could be...

Yeah I'm in Denver area. I thought I saw an 80*** zipr code in you location, my bad.

Now way to tell with inspecting.

 

[stephen0]

Yeah I'm in Denver area. I thought I saw an 80*** zipr code in you location, my bad.

Now way to tell with inspecting.

Are you aware of any current aftermarket CAT options for the 06-07 that are decent. I've been digging with not much luck. Plan to dig into what might have caused the CAT to go bad if indeed that has happened.

 

[jerryb]

@KYLandy are you still using the urd 4.7 sim? Did you ever measure the output mV? do you still have it?

Or did you buy the universal one? maybe I should explain better, I think they had a specific one for for LC LX 06-07 and whatever matching makes and models specifically but then took it away in favor of a universal one.

 

[2001LC]

Are you aware of any current aftermarket CAT options for the 06-07 that are decent. I've been digging with not much luck. Plan to dig into what might have caused the CAT to go bad if indeed that has happened.

See post:P0420 and P0430 - 2006 LC
This was on one I'm working on. So I bought same for other side.
Good:
Bolt on.
Has small heat shield. (bigger, covering more area would be better)
I found for $300 to my door.
Bad:
Heat shield although it has one and most do not, is perhaps to small.
CAT material is smaller than OEM. But seems to work just fine.
Comes with junky gaskets. OEM are better.


Note: The one I did buy. Was missing the 18mm plug. I was able to buy a plug at parts store. But not the crush washer. For crush washer I purchased AC Delco O2 washers G18mm.

 

[lehiguy]

I keep getting a P0420. I clear the code and it returns the same day. Attached is some info i pulled my my cheap code reader. Something looks off. Anybody want to translate that into layman's terms for me?

 

[2001LC]

Let me ask me ask; With what did you read the read the code (DTC) and any other codes now or in recent past?
Any other issues?

CAT can be difficult to diagnose. If a bad O2 or A/F sensor(s) you should get a DTC (code) indicating that. But not always. If CAT bad, you must find what the upstream issue is first. Than once upstream corrected, recheck CAT.

Unless you've tech stream and experienced at diagnosing. You'd be best off finding a 100 series specialist that understand how. Not just some corner shop.

 

[lehiguy]

I'm thinking the high long-term fuel trim numbers and the P0420 means I have a vacuum leak somewhere.