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  #1  
Old 02-03-2010, 12:35 PM
slug slug is offline
2004 Ranger Edge 4x4 5spd
 
Join Date: Feb 2010
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Default P0420 Engine Code

I'm getting an occasional P0420 code from my engine light warning.

I have a 2004 Edge with 4.0 engine and 4x4 drive train. Manual 5 spd transmission. I only have 22k miles on it.

The shop read-out shows possible misfire, vacuum leak, catalytic convertor failure. Also it mentioned possible engine oil leakages. I think also this would include the oxygen sensor post-convertor. I have had the rear sensor changed once due to mice eating the O2 sensor wires. But I looked last night and the wires are ok.

The code is probably being thrown once every few weeks or so.

I have not done plugs or spark wires since new. Nor have I regreased any connections with dielectric grease. And I haven't started to check vacuum lines.

But I recognize that even with the low mileage, the truck is after-all 6 years old, and corrosion and age do begin to rear their ugly heads.

I'm thinking to begin a general tune-up (plugs, plug wires, various filters, air-intake clean-up, etc.), since it never hurts.

But I'm wondering if you other Ranger members have a feel for what this code usually means?

Thanks!

slug

(note: I think my post title is wrong. should be "P0420" probably. Maybe that's why I didn't get any search hits).

(ok, corrected now)

Last edited by slug; 02-03-2010 at 01:05 PM. Reason: typo error
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  #2  
Old 02-03-2010, 02:36 PM
caliedge caliedge is offline
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A PO420 is usually a code that is stating that there is somthing upstream from the converter that is causing the code to come up at the end of the drive cycle. A PO420 code can be anything from a bad o2 sensor to timing of the vehicle. stating this dont just replace the converter to get rid of the code find the source of the issue. A converter is a passive product meaning that it will not fail unless something upstream is making it fail. i deal with this on an everyday basic since it is what my job is.
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  #3  
Old 02-03-2010, 02:55 PM
Tom Tom is offline
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Quick google search came up with this:

Quote:
P0420: 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.
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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 error 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.


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  #4  
Old 02-04-2010, 09:22 AM
caliedge caliedge is offline
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that is a good find!
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  #5  
Old 02-04-2010, 12:47 PM
Jp7 Jp7 is offline
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Quote:
i deal with this on an everyday basic since it is what my job is.
That scares me, considering nearly everything you've posted above is wrong.
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  #6  
Old 02-04-2010, 12:56 PM
Jp7 Jp7 is offline
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OBD2 software monitors the voltage from the primary and secondary hegos as fed through the ecu to verify that the oscillation on the secondary hego is of a lower amplitude with the nominal being the stoich center line. If the secondary hego is of equal amplitude, or within a certain threshold of the first then the software will throw a P0420.

2 ways around this.

1) Use defouler spacers on the secondary hego to space the nose from the flow
2) Reprogram the software so the computer forces it to pass.

Option 2 is better, but not everyone has open source software to convert thier rom into XML to edit the code like I do.
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Quote:
Originally Posted by FireRanger View Post
I'm dying to see this at night. Someone go tell the sun to give up already.
Quote:
Originally Posted by beef08 View Post
Your the man, you bring our dreams to a reality within the lighting spectrum
Quote:
Originally Posted by BCobe View Post
Jp7 you always do AMAZING work! Hats off to you sir
Quote:
Originally Posted by FireRanger View Post
People so often confuse "hating" with "knowing better".
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  #7  
Old 02-04-2010, 01:50 PM
caliedge caliedge is offline
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so what you are stating is if the o2 are throwing a PO 420 code to replace the converter? i was just letting him know from personal exsperience that that is not always a case. There is an old saying in the converter manufacturing business that "a converter does not die it is killed" a converter is a 100% passive product.
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  #8  
Old 02-04-2010, 05:06 PM
Jp7 Jp7 is offline
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Quote:
so what you are stating is if the o2 are throwing a PO 420 code to replace the converter?
Where did I say that?

Hego's do not throw any codes. They simply respond with a voltage that is a function of the oxygen content it smells.

Quote:
i was just letting him know from personal exsperience that that is not always a case. There is an old saying in the converter manufacturing business that "a converter does not die it is killed" a converter is a 100% passive product.
Defective parts are made in all aspects of manufacturing.

I do agree with the spirit of your statement that the code is likely a symptom of a problem upstream.
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Quote:
Originally Posted by FireRanger View Post
I'm dying to see this at night. Someone go tell the sun to give up already.
Quote:
Originally Posted by beef08 View Post
Your the man, you bring our dreams to a reality within the lighting spectrum
Quote:
Originally Posted by BCobe View Post
Jp7 you always do AMAZING work! Hats off to you sir
Quote:
Originally Posted by FireRanger View Post
People so often confuse "hating" with "knowing better".
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  #9  
Old 02-04-2010, 05:16 PM
Jimbo Jimbo is offline
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Chill out boys
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  #10  
Old 02-07-2010, 12:58 PM
slug slug is offline
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Thanks guys for all the info! (I have gotten a little over-passionate also about car things. You guys are actually fairly mild )

This P0240 code I think is really a bit of a "can of worms". I need to just keep checking things out and see what I find (I have actually found a mouse nest in one of my Pontiac Bonnevilles intake horns. That could throw a code that they don't teach you about).

I'm use to using an Actron 9110 scanner on our old OBD1.5 Bonneville. This would give me much much more than codes and would record O2 sensor characteristics and such. I have been intending to set up a laptop with OBD2 diagnostic software for some time now, but just haven't gotten around to it yet.

Caliedge--you mentioned some unfamiliar terms to me:

A hego is an O2 sensor? (where did that term come from?)

What are defouler spacers?

How do you reprogram the software? Do you mean you can hook up a handheld computer to the Ranger ECU like the Japanese jobs can do?

Ok, interesting stuff!

Thanks again,

slug
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  #11  
Old 02-07-2010, 04:04 PM
Jp7 Jp7 is offline
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Quote:
A hego is an O2 sensor? (where did that term come from?)
Heated Exhaust Gas Oxygen Sensor


Quote:
What are defouler spacers?
They are supposed to be for spacing back spark plugs. Same threads as a Hego Bung.

Quote:
How do you reprogram the software? Do you mean you can hook up a handheld computer to the Ranger ECU like the Japanese jobs can do?
You need access to be able to download and modify your ROM. I use EcuFlash for Mitsubishi and Subaru.

Quote:
Ok, interesting stuff!

Thanks again,
Anytime.
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Looking for a professional retrofitter to add HIDs or LEDs to your Ranger? PM me if your looking to have work done, and have cash to spend.

Quote:
Originally Posted by FireRanger View Post
I'm dying to see this at night. Someone go tell the sun to give up already.
Quote:
Originally Posted by beef08 View Post
Your the man, you bring our dreams to a reality within the lighting spectrum
Quote:
Originally Posted by BCobe View Post
Jp7 you always do AMAZING work! Hats off to you sir
Quote:
Originally Posted by FireRanger View Post
People so often confuse "hating" with "knowing better".
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  #12  
Old 02-08-2010, 11:36 AM
slug slug is offline
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Quote:
Originally Posted by Jp7 View Post
You need access to be able to download and modify your ROM. I use EcuFlash for Mitsubishi and Subaru.
Thanks for those clarifications!

Can EcuFlash (or something like it) be used on 2004(ish) Rangers?

How would you get access? This is interesting stuff.

slug
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  #13  
Old 02-08-2010, 11:42 AM
Jp7 Jp7 is offline
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Quote:
Originally Posted by slug View Post
Thanks for those clarifications!

Can EcuFlash (or something like it) be used on 2004(ish) Rangers?

How would you get access? This is interesting stuff.

slug
No because I don't think there is open source software (the ROMs arent available to modify with open source software). You would need to buy a tuner. The tuners are very limited compared to what you can do with open source software.
__________________
Looking for a professional retrofitter to add HIDs or LEDs to your Ranger? PM me if your looking to have work done, and have cash to spend.

Quote:
Originally Posted by FireRanger View Post
I'm dying to see this at night. Someone go tell the sun to give up already.
Quote:
Originally Posted by beef08 View Post
Your the man, you bring our dreams to a reality within the lighting spectrum
Quote:
Originally Posted by BCobe View Post
Jp7 you always do AMAZING work! Hats off to you sir
Quote:
Originally Posted by FireRanger View Post
People so often confuse "hating" with "knowing better".
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  #14  
Old 02-09-2010, 12:54 PM
slug slug is offline
2004 Ranger Edge 4x4 5spd
 
Join Date: Feb 2010
Posts: 7
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Ok, so this is something that probably nobody messes around with on Rangers? I was just wondering.......

So I'll probably stick to just some kind of good diagnostic software for a laptop that can be used generally for OBD2 type cars and trucks.

I know there's people getting into this to help supply electronics, cables and software for OBD2-type amateurs. I'll have to do a search in this club (and maybe the other big Ranger club) to see if anyone's tried it yet for Rangers. I aim to set up a good OBD2 laptop scanning system some day.
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  #15  
Old 02-09-2010, 01:47 PM
Jp7 Jp7 is offline
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Quote:
Ok, so this is something that probably nobody messes around with on Rangers? I was just wondering.......
Yes, its not really a tuner car.
Quote:
So I'll probably stick to just some kind of good diagnostic software for a laptop that can be used generally for OBD2 type cars and trucks.

I know there's people getting into this to help supply electronics, cables and software for OBD2-type amateurs. I'll have to do a search in this club (and maybe the other big Ranger club) to see if anyone's tried it yet for Rangers. I aim to set up a good OBD2 laptop scanning system some day.
If your desperate you can go with a stand alone ECU.
__________________
Looking for a professional retrofitter to add HIDs or LEDs to your Ranger? PM me if your looking to have work done, and have cash to spend.

Quote:
Originally Posted by FireRanger View Post
I'm dying to see this at night. Someone go tell the sun to give up already.
Quote:
Originally Posted by beef08 View Post
Your the man, you bring our dreams to a reality within the lighting spectrum
Quote:
Originally Posted by BCobe View Post
Jp7 you always do AMAZING work! Hats off to you sir
Quote:
Originally Posted by FireRanger View Post
People so often confuse "hating" with "knowing better".
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