Codes P0420 and P0430

Tiny
STILLHOPING26
  • MEMBER
  • 2009 NISSAN MAXIMA
  • 3.5L
  • V6
  • AUTOMATIC
  • 195,000 MILES
I have just replaced my motor. The check engine came on. The code is p0420 and p0430. Say it is about the catalytic converter. Can you tell me anything to do?
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Monday, May 28th, 2018 AT 2:47 PM

17 Replies

Tiny
STEVE W.
  • EXPERT
Your old engine was missing and running poor and these codes show the unfortunate problem that caused. Both of those codes are for catalytic converter low efficiency. AKA, they are not working as they should. The first thing would be to verify that there is not something else wrong first. This code could be caused if the wiring for the front and rear O2's were to get reversed when the swap was done. Simply looking at the live data from the sensors should show if that is the case as the "rear" sensors would be switching fast and the "front" sensors would be steady.
If that is not the case then you could try one of the supposed converter cleaners and see if the issue was just soot or oil that built up from the misfire. I do not place much faith in that and think you might want to run it some and get them heated up and see if the converters burn themselves clean. However, the probable final fix will be to replace the converters on both banks. Not an uncommon issue with a worn engine and misfires as the raw fuel can destroy a converter in a short amount of time.
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Monday, May 28th, 2018 AT 8:26 PM
Tiny
KHLOW2008
  • EXPERT
Hi STILLHOPING26,

P0420 is a fault with bank 1 catalytic converter.
P0430 is a fault with bank 2 catalytic converter.
Check the exhaust system at the exhaust manifold for leakages, which should be distinguishable by louder than normal noise from engine while running at idle and minor acceleration.
Check the exhaust sensors for proper connection of wiring circuits. If this code was present prior to replacing the engine, most probably the catalytic converters or exhaust sensors are faulty.
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Monday, May 28th, 2018 AT 8:36 PM
Tiny
STILLHOPING26
  • MEMBER
No the codes came after I replaced the motor. I had codes of the camshaft sensor with older motor.
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Saturday, June 2nd, 2018 AT 3:36 PM
Tiny
STEVE W.
  • EXPERT
Unfortunately the way that system works it is very likely that the misfires and poor running of the old engine caused the converters to fail. That is why I suggested looking at the things like wiring and testing the sensors. An exhaust leak could cause this as well, but you should hear that.
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Saturday, June 2nd, 2018 AT 6:14 PM
Tiny
STILLHOPING26
  • MEMBER
  • 2009 NISSAN MAXIMA
  • 3.5L
  • V6
  • AUTOMATIC
  • 195,000 MILES
I recently replaced engine. I was hoping when I did that no problems, but I was not so luckily. I have the codes of p0430 and p0420, and the A/C was working for three days. All of a sudden it quit cooling. It blows cool for about two minutes then cool air goes away. It does that every now and then. So basically cool air gone. I have checked the Freon it is full. It as a new one.
I cannot remember if I asked this before, but my oil was changed and he put O'reilly 5w30 in it. I had bought Valvoline synthetic 5w30 to be added. Do you think it would have anything to do with the codes coming up? Do I need to put the synthetic one in? Also, what do you think about the codes and air? New engine I put in suppose to have 44,000 miles on it. Help please.
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Monday, June 4th, 2018 AT 11:32 AM (Merged)
Tiny
STEVE W.
  • EXPERT
The oil would not cause this and I would use the oil in it as a "flush" being it's a used engine. Run it a bit (200 to 300 miles then change it. See what it looks like coming out.

The codes are likely from damage done by the old engine. They mean that the converters are not working properly. If you read through the replies above you will see some recommendations of things to check. However, the way the engine monitors work it most likely did not run the tests on the converters with the old engine running poorly. Then the "new" engine was installed and it ran the tests and shows that the converters are bad. Not an uncommon thing to see after doing this type of repair.
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Tuesday, June 5th, 2018 AT 5:39 AM
Tiny
STILLHOPING26
  • MEMBER
What did you think about AC problem?
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Tuesday, June 5th, 2018 AT 10:22 AM
Tiny
STILLHOPING26
  • MEMBER
Also, can you tell me where the AC pressure sensor is located?
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Tuesday, June 5th, 2018 AT 1:33 PM
Tiny
STEVE W.
  • EXPERT
The AC could be a switch, wiring or low or high charge. You say you checked it. What were the pressures with the compressor running and what was the ambient temperature during the test?
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Tuesday, June 5th, 2018 AT 3:14 PM
Tiny
STILLHOPING26
  • MEMBER
Hello, I found out it is the other wire coming from the car that hooks into the compressor. I am sending a picture so you can see somewhat I mean. Someone told me to get a pigtail but I do not know the name of it. Can you tell me the name of part I will need? I have a piece of tape on it but it keeps coming loose. Well, I tried add picture, but it would not work.
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Sunday, June 17th, 2018 AT 12:11 PM
Tiny
KEN
  • ADMIN
What will not work about the picture upload? Here is a test I just did:
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Monday, June 18th, 2018 AT 9:57 AM
Tiny
STILLHOPING26
  • MEMBER
I tried again, and it uploaded. I wanted to know the name of part that hooks off into that part in the picture.
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Monday, June 18th, 2018 AT 10:29 AM
Tiny
KEN
  • ADMIN
Did you ever get the code issue straighten out? Please start a new question for you AC issue.

Please post your new question here

https://www.2carpros.com/questions/new

Cheers, Ken

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Monday, June 18th, 2018 AT 10:54 AM
Tiny
STILLHOPING26
  • MEMBER
I had ask about AC already in the new question.
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Monday, June 18th, 2018 AT 10:57 AM
Tiny
STEVE W.
  • EXPERT
That wire that is unhooked goes to the AC clutch. With it disconnected the AC will not function. There should be a connector that plugs into it right in the area.
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Monday, June 18th, 2018 AT 11:48 AM
Tiny
STILLHOPING26
  • MEMBER
I know, I was asking what is the name of that connector that plugs into the AC clutch? It has a shortage in it.
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Monday, June 18th, 2018 AT 8:21 PM
Tiny
STEVE W.
  • EXPERT
There really is not a name for it. It is simply the AC clutch circuit. There would be a connector number but it is not a part number or usable to locate a part. Shorts are generally easy to locate. However, it might be easier to simply run a new wire if it has shorted, although I would rather find the problem as it could involve more than one wire shorting out.
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Tuesday, June 19th, 2018 AT 2:25 PM

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