P0420 and P0430 - 2006 LC (29 Viewers)

[2001LC]

I had both 420 & 430 codes so I replaced both sensors on the driver's side (bank 1), they all looked like they had already been replaced by the PO, but regardless I did it anyway and, no change. The 02 sensor route should always be tried first (at least on one side) to see if any change occurs.
It is an awesome vehicle and for $800.00 I went for the jugular of repairs and got it done right!
I was also afraid of fuel trim which the engine changes to compensate for the P420 & P430 lights being on. Enough fuel trim over enough time can ruin your engine via wall wash, & melted pistons etc... caused by too much fuel.

Just a final follow-up 3 months after my replacement cats were installed. I have not had ANY reoccurrence of my codes since installing the direct fit catalytic converters that I found on eBay. Problem is completely solved after 3 months of trouble free driving.

Glad to hear it's worked out.

To be clear; you changed out the A/F & O2 sensors on just bank bank 1 as a test, rather than doing both banks?

Your statement "they all looked like they had already been replaced by the PO", indicates PO had issue and possible waited to long to correct, damaging CATS (if that's possible).

Perhaps someone above my paygrade can chime-in and tells us if running with these codes (running poorly, rich or lean) can damage CATs reducing expect life?

 

[RECRUISER]

Good discussion question. My understanding is that the codes appear because the catalytic converter is below threshold already. Meaning that it is not doing it's job properly, thus the codes.
Yes I replaced Just One Bank of O2 sensors to see if they were the problem. When the problem persisted I proceeded to change out the cats.
hope this answers your question and thank you for chiming in on this discussion.

 

[archie]

Update on my codes. About two month ago I went Chicago to Toronto Round trip and had CEL go off only once at low speeds. About a month ago I went Chicago to NYC round trip and used 2 bottles of fuel injector cleaner (one each way). I did not have any codes since. It has been over a month now. Just wanted to share my observations and maybe it might help in your situation.

 

[BullElk]

My story....A couple months ago I replaced all four O2 sensors after getting a codes PO138 and PO158. The sensor replacements cured the codes. Today I get the PO430 code. I wonder if the Kwiksen brand sensors could be my problem.

 

[nissanh]

420 and 430 are for cat, correct? I got it on pass side and cleared the code. In 107 miles, got the code again. Then knowing Pd, Rh and Ir that is inside the cat never goes bad, I went with Scotty Kilmers method. That is at half tank (10 gallons), I added a gallon of laquer thinner into the gas tank pre diluted with two or 3 gallons of gas (pure thinner can damage rubber hoses between the filler cap and gas tank). Drove about an hour at 60 ish Mph with rpm at 2 to 3000. Now I did 210 miles and no codes so far
See Scotty's video. Laquer thinner is about $16 at home depot.

 

[looking4lc]

it looks like the rear O2 Sensors did the trick

no code for 3 weeks now

code P0430 came back after replacing both dowbstream o2 sensors less than 2 years now. is it possible? time for upstream?

 

[BullElk]

As mentioned above, I get the PO430 code every once in awhile now. I put a can of Berryman B12 in gas and it goes clears it for awhile.

 

[OEMGUY0720]

Got mine today guys, can anyone confirm that this about right?

Its 234k++ miles now..

Pulled out the O2 sensors and this is their current condition:

 

[OEMGUY0720]

Update on my upstream O2s (or AFs in other terms). I installed these new ones (damn these are expensive from the local toyota dealership cost me around $505 for both) and CEL went off immediately as soon as I started the engine.

 

[OEMGUY0720]

However it’s been 3 days now I am getting P0430. I am able to clear it using Techstream but it keeps on coming back every time I use the truck for short 20-30 miles errand trips.

Things I’ve done so far:
• Replaced all 8 spark plugs with Denso Iridium

• Replaced both downstream O2 sensors with Denso I got from O’Reilly ($190 for both), P0430 still showing up on Techstream.

• I saw no leaks, fluid level on the radiator and reservoir hasn’t change (any other spots suggested to look at for leaks?)
• Checked air filter -its OE paper type still clean.
• Checked MAF sensor near the air filter and it was clean, felt didn’t had to clean it so I didn’t sprayed anything on it or wipe it as it was really clean.
• Gas cap is OE from stealership relatively new as well I replaced it same time I replaced my two upstream O2 sensors.


From what I read here, my plan of attack:

• Remove and check both upstream O2 sensors (same one I replaced a couple of months ago)
• check PCV valve and grommet and go ahead replace it
• check for leaks on the exhaust manifold (is there an inexpensive way to do this and how?)
• will try to pour “BERRYMAN B12” or “CATACLEAN”.
• consider to pour lacquer thinner on the gas tank.

Any other suggestions or help are much appreciated. Thanks @2001LC for directing me back to this thread.

 

[nukegoat]

420 and 430 are for cat, correct? I got it on pass side and cleared the code. In 107 miles, got the code again. Then knowing Pd, Rh and Ir that is inside the cat never goes bad, I went with Scotty Kilmers method. That is at half tank (10 gallons), I added a gallon of laquer thinner into the gas tank pre diluted with two or 3 gallons of gas (pure thinner can damage rubber hoses between the filler cap and gas tank). Drove about an hour at 60 ish Mph with rpm at 2 to 3000. Now I did 210 miles and no codes so far
See Scotty's video. Laquer thinner is about $16 at home depot.

Don't listen to Scotty kilmer

 

[looking4lc]

However it’s been 3 days now I am getting P0430. I am able to clear it using Techstream but it keeps on coming back every time I use the truck for short 20-30 miles errand trips.

Things I’ve done so far:
• Replaced all 8 spark plugs with Denso Iridium
View attachment 2032426
• Replaced both downstream O2 sensors with Denso I got from O’Reilly ($190 for both), P0430 still showing up on Techstream.
View attachment 2032429
• I saw no leaks, fluid level on the radiator and reservoir hasn’t change (any other spots suggested to look at for leaks?)
• Checked air filter -its OE paper type still clean.
• Checked MAF sensor near the air filter and it was clean, felt didn’t had to clean it so I didn’t sprayed anything on it or wipe it as it was really clean.
• Gas cap is OE from stealership relatively new as well I replaced it same time I replaced my two upstream O2 sensors.


From what I read here, my plan of attack:

• Remove and check both upstream O2 sensors (same one I replaced a couple of months ago)
• check PCV valve and grommet and go ahead replace it
• check for leaks on the exhaust manifold (is there an inexpensive way to do this and how?)
• will try to pour “BERRYMAN B12” or “CATACLEAN”.
• consider to pour lacquer thinner on the gas tank.

View attachment 2032436
View attachment 2032437
Any other suggestions or help are much appreciated. Thanks @2001LC for directing me back to this thread.

adding additive cleaner in gas tank is effective way to clear it. try it, i used Marvel mystery oil and worked after 30 miles.

 

[OEMGUY0720]

adding additive cleaner in gas tank is effective way to clear it. try it, i used Marvel mystery oil and worked after 30 miles.

Just 30miles and CEL was back again? I got the Cataclean now and will try that tomorrow when my gas tank hits 1/4 level as prescribed on the bottle.

The guy in O’Reilly said the Cataclean is different from Berryman he said Cataclean is specific for the cats while the Berryman is specific for the injectors. Any experience with these products? Does it deliver as advertised?

Update as of today:
• checked upstream O2s:
-driver side was a pain to remove and putting it back -treads were tight but was able to do it, pulled it out and seemed fine still looks new (2months old only), added generous amount of anti-seize grease on it from Denso left overs.
-passenger side upstream O2 sensors was very easy to remove, so easy I think it wasn’t installed tight enough back when I put this in (my bad when I did this 2 months ago). Also looked fairly new, swabbed generous amount of anti-seize grease when I put back. Could that be leak?

• checked PCV and discovered it’s not oem anymore

 

[OEMGUY0720]

Update on my P0430 2006LX470:

I have the same issue for past 2-3 weeks now, here’s the list that I have performed so far:

P0430 error:
• cleaned MAF and Throttle: P0430 still
• replaced all 8 spark plugs with Denso Iridums: P0430 still
• sprayed battery cleaner: P0430 still
• replaced PCV valve OEM part # 12204-50030: P0430 still
• poured CATACLEAN on 1/4 remaining gas: P0430 still
• poured Berryman on 1/4 remaining gas: P0430 still
• replaced downstream O2 sensor Bank2 Denso 234-4260 (OE with plug): P0430 still
- replaced Fuel Pump Denso # 950-0210: P0430 still
- used downstream O2 sensor from Bank1 (known to be working): P0430 still
**gas cap recently replaced with OEM genuine gas cap
**added a condenser fan to help ventilate the AC system

What else am I missing gents?

 

[2001LC]

Update on my P0430 2006LX470:

I have the same issue for past 2-3 weeks now, here’s the list that I have performed so far:

P0430 error:
• cleaned MAF and Throttle: P0430 still
• replaced all 8 spark plugs with Denso Iridums: P0430 still
• sprayed battery cleaner: P0430 still
• replaced PCV valve OEM part # 12204-50030: P0430 still
• poured CATACLEAN on 1/4 remaining gas: P0430 still
• poured Berryman on 1/4 remaining gas: P0430 still
• replaced downstream O2 sensor Bank2 Denso 234-4260 (OE with plug): P0430 still
- replaced Fuel Pump Denso # 950-0210: P0430 still
- used downstream O2 sensor from Bank1 (known to be working): P0430 still
**gas cap recently replaced with OEM genuine gas cap
**added a condenser fan to help ventilate the AC system

What else am I missing gents?

IDR, what is your year and miles?

 

[OEMGUY0720]

@2001LC 2006LX with 235k miles

 

[2001LC]

Looking at your spark plug (slight lean burning look) and year 06. Fuel pump is what I'd try next, which seems you are, by what you posted in 2005-2007 fuel pump denso #950-0210 instead of 23220-50160

I'll be very interested in your results. One thing to consider; Lets say engine is burning lean, then fuel pump corrects issues. Then question if CAT or 02 DTC comes up again. Did a lean condition damage these components.

Stalling not just in High, Hot, & Heavy

forum.ih8mud.com

 

[white_lx]

2006LX with 235k miles

The photo of the used plug in post #290 shows 'JAPAN'. Are those the original plugs at 235k miles?

 

[2001LC]

Good question @white_lx . Gap would be telling. If 235K miles on plug I'd bet over 1.2mm gap even 1.3mm.

 

[white_lx]

Good question @white_lx . Gap would be telling. If 235K miles on plug I'd bet over 1.2mm gap even 1.3mm.

Plugs were replaced per the above list of work done. But was there cat damage as result of deferred maintenance?