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Discussion Starter · #1 ·
I recently installed the DT y-pipe, which replaces the 2nd pair of cats.


Since then, i have gotten the P0420 code twice. Cleared it the first time, came back 2 minutes later, cleared it, and has not popped up since. That was over a week ago.


3 days ago, i got the P0430 code. Cleared it, has not been back since.


OBD-II Trouble Code: P0420 Catalyst System Efficiency Below Threshold (Bank 1)

I've got no symptons for that..


OBD-II Trouble Code: P0430 Catalyst Efficiency Below Threshold (Bank 2)

Now for that one, a couple of random times i have had a disgusting sounding/rough idle.. sounded like it was burning sand, not gasoline.



Is the computer just outsmarting me again? The 2nd set of cats are AFTER the 2nd O2 sensor.. How would it know??

This is making me think maybe something is wrong with the 1st cat's. Is that possible?




P.S. I checked all the bolts underneath, all tight, no leaks.


I'd like to hear what you guys have to say before i have to take it in. :bigthumb:
 

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I'm reposting the info on OBD-II Trouble Codes - OBD-II DTC Trouble Codes Repair Help Site:
Catalyst System Efficiency Below Threshold (Bank 1)
What does that mean?

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms

You will likely not notice any drivability problems, although there may be symptoms.
Causes

A code P0420 may mean that one or more of the following has happened:

* Leaded fuel was used where unleaded was called for
* An oxygen sensor is not reading (functioning) properly
* The engine coolant temperature sensor is not working properly
* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
* Retarded spark timing
* The oxygen sensors in front and behind the converter are reporting too similar of readings

Possible Solutions

Some suggested steps for troubleshooting a P0420 code include:

* Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
* Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
* Inspect the downstream heated oxygen sensor (HO2), replace if necessary
* Replace the catalytic converter

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.



This is for p0430.

Catalyst System Efficiency Below Threshold (Bank 2)
What does that mean?

Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms

You will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.
Causes

A code P0430 may mean that one or more of the following has happened:

* The catalytic converter is no longer functioning properly
* An oxygen sensor is not reading (functioning) properly
* There is an exhaust leak

Possible Solutions

First, inspect for exhaust leaks.

Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.



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Is it possible that it is leaking eventhough you don't think it is? Maybe have a muffler shop take a look?
 

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I'm not sure if there is a difference b/w the sensors, but I noticed the wires are not equal lengths for the 02 sensors, did you make sure to put them back on the corresponding side when reinstalling?
 

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Did you get a chance to talk to DT or URD? I would contact them first since the code occurred after the installation of their parts right?
 

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Hey, did you happen to replace the gaskets with new ones??? I stopped by my dealership to pick up some royal purple (for 8.75 a piece with my 10% coupon, yah!) and got the two that go between where it mounts to the precats. There is also one where they join and go to the intermediate pipe. It is larger. (the prices are 9 bucks and then 22 bucks, respectively) I held out on the more expensive one because it still looked in shape. The other two were all burnt up. Maybe try replacing these as well?
 

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Discussion Starter · #7 ·
Hey, did you happen to replace the gaskets with new ones??? I stopped by my dealership to pick up some royal purple (for 8.75 a piece with my 10% coupon, yah!) and got the two that go between where it mounts to the precats. There is also one where they join and go to the intermediate pipe. It is larger. (the prices are 9 bucks and then 22 bucks, respectively) I held out on the more expensive one because it still looked in shape. The other two were all burnt up. Maybe try replacing these as well?
Don't tell me these are one time use gaskets... ? :crbaby:
 
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