Code P0430
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From: MN
Code P0430
I have been clearing code P0430 several times during the last few days. The message states, "Catalyst System Below Threshold, Bank 2". It also shows VSC. I have been running non-oxy gas for months now, if that might affect this. The weather has been extremely wet with heavy fog and temps hovering above the freezing point for days, if that is a factor. The car runs well, whether the dash warning lights are on or not. I have just filled back up from 1/4 tank to full, with premium unleaded instead of the non-oxy. I'm assuming the "Below threshold" means lean, but I'm not aware of cylinder misfires. I suppose an exhaust leak could have occurred, but I don't hear it.
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Joined: Mar 2018
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From: ESSEX, UK
Most commonly caused by a leak in or near where the Y-pipe joins the primary CATs.
Mine was a crack in the weld where the flange attaches to the Y-pipe.
This lets air into the exhaust so the downstream sensors detect too much oxygen and cause the error.
You won't hear any change in the sound of the exhaust but it's pretty obvious when you have her up on a ramp and idling.
Mine was fixed with a new Y-pipe.
Mine was a crack in the weld where the flange attaches to the Y-pipe.
This lets air into the exhaust so the downstream sensors detect too much oxygen and cause the error.
You won't hear any change in the sound of the exhaust but it's pretty obvious when you have her up on a ramp and idling.
Mine was fixed with a new Y-pipe.
Last edited by BigBoomer; Jan 2, 2025 at 03:00 AM.
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Joined: Dec 2024
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From: MN
I took a long drive yesterday. It was about 170 miles round trip. The code did not appear the entire way. Later I took a short drive, about 4 miles. It did not appear. On the return trip the code came up. The short drive is my daily routine x 2. This does seem to indicate an exhaust leak, since the highway drive would have been at a constant throttle, rpm and exhaust system pressure, while the short drive would be fluctuating and therefore possibly allow for ambient air to enter the exhaust stream from a leak.
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From: MN
The "event" thing is something I was not aware of. It makes sense. I drive about 4 miles one way and park it for a while. Then a couple of hours later, I drive back. I do this twice a day and notice the code pops up on the second drive or return trip. The 170 mile trip was split into several starts, but basically 2 runs of about 1/2 and 1/2. I'm going to pay closer attention to this "2 event" deal from now on. Thanks for the heads up!
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Joined: Sep 2023
Posts: 16
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From: IL
Most commonly caused by a leak in or near where the Y-pipe joins the primary CATs.
Mine was a crack in the weld where the flange attaches to the Y-pipe.
This lets air into the exhaust so the downstream sensors detect too much oxygen and cause the error.
You won't hear any change in the sound of the exhaust but it's pretty obvious when you have her up on a ramp and idling.
Mine was fixed with a new Y-pipe.
Mine was a crack in the weld where the flange attaches to the Y-pipe.
This lets air into the exhaust so the downstream sensors detect too much oxygen and cause the error.
You won't hear any change in the sound of the exhaust but it's pretty obvious when you have her up on a ramp and idling.
Mine was fixed with a new Y-pipe.
Last edited by tealchief; Jan 4, 2025 at 12:53 PM.
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Thread Starter
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From: MN
Thanks. I'll get it up on my hoist soon. I have a 2002 LS as well. It's actually my brother's car now. It has a pretty good leak at the flange (corrosion). I'm wondering when that one will have this code. I did try to patch it up with some epoxy and mesh. Kind of a hack job, temp fix. Its tight to work in that area and I didn't want to get into it further at the time. Once I have my 2004 LS up on the hoist, I'll determine the situation and possibly even weld it up. It may be time for some cutting and splicing.
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From: North Carolina
This was years ago and I can't remember where I read it but do remember it was correct for code produced that didn't happen right away. I think it was the evap problem then. I have the full manuals and could have read it there but not sure. I do remember on my Tundra the air pump that only works on start up to purge gases will force limp mode and when clear code I think it took 3 starts before code would come back and the forum was talking about that.
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From: MN
Thank you for the reply. I use a blue driver scan tool that utilized my cell phone for readout. It is small, inexpensive and works well. I have other scan tools, but I like this one for its size. I can easily leave it in the car, and it is hidden under the steering column. That is nice for not having to reach under the dash to connect it multiple times, since it does not interfere with normal vehicle functions while connected. That's a plus for chasing this problem, due to the multiple resets. It also has a mileage logging feature that allows me to enter the mileage at reset. I also have a Tundra. 2007 SC, SB, 5.7L, rear drive only. It came with the TRD exhaust, buckets, console and shifter but no towing features like trans temp & cooler, hitch or trailer brake. It is a "Sport Package" so has a more cosmetic rear bumper than the standard step one. I did install a class 3 hitch and brake. I haven't got around to the trans cooler and temp ga yet, although I do have the parts. I have only had since new in 2007. I didn't want to hurry
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Joined: Jan 2004
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From: North Carolina
Thank you for the reply. I use a blue driver scan tool that utilized my cell phone for readout. It is small, inexpensive and works well. I have other scan tools, but I like this one for its size. I can easily leave it in the car, and it is hidden under the steering column. That is nice for not having to reach under the dash to connect it multiple times, since it does not interfere with normal vehicle functions while connected. That's a plus for chasing this problem, due to the multiple resets. It also has a mileage logging feature that allows me to enter the mileage at reset. I also have a Tundra. 2007 SC, SB, 5.7L, rear drive only. It came with the TRD exhaust, buckets, console and shifter but no towing features like trans temp & cooler, hitch or trailer brake. It is a "Sport Package" so has a more cosmetic rear bumper than the standard step one. I did install a class 3 hitch and brake. I haven't got around to the trans cooler and temp ga yet, although I do have the parts. I have only had since new in 2007. I didn't want to hurry
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Joined: Dec 2024
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From: MN
This is the first I have heard of this. I wonder if the 2007 model year was somehow not included. I'm going to check now. My truck only has 40 K on it, but I don't see low miles as something that would be less subject to corrosion. The age would be a greater factor, in my opinion. Thanks for the heads up!
Racer
Joined: Jan 2004
Posts: 1,945
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From: North Carolina
This is the first I have heard of this. I wonder if the 2007 model year was somehow not included. I'm going to check now. My truck only has 40 K on it, but I don't see low miles as something that would be less subject to corrosion. The age would be a greater factor, in my opinion. Thanks for the heads up!