Hi folks I am new to the forum, so I am not sure how this is supposed to be done. I have been having code problems with my o4 ram 4.7 liter, specifically the P0420, I have been reading all kinds of suggestions and thoughts about this(from the forum),this is a catalitic converter code that says bank one cat one's efficiency is below threshold. I tried using my OBD2 to clear the codes but it kept comming back, the common thought is that it is the cat, and that it is a waste of time and money replacing the O2 sensors, just bite the bullit and change the cat, and I am not saying that might not be trur in most cases. But I looked to the easiest and cheapest ways people had gotten around that, I still have not checked the temp of the cat upstream and downstream "yet" which is next if what I did does not continue to work, that said one of the easy fixes someone mentioned was to unhook the negative battery cable and sand down the surface it attaches too to make sure you are getting a good tight uncoroded connection, the other was if you had had an engine missfire code sometime in the past, that that code still being in the PCM could cause the P0420 code and to just disconnect the negative battery cable for about 15 minutes and then the PCM would re-set. Now I agree that these sound pretty hoaky and doubtfull, but they are free and both can be accomplished at the same time. So I cleared the codes with my OBD2 and then I tried them 4 days ago, and still no codes ?????????? is this possible, or am is the light just going to come back shortly.

 

hey and wellcome

I do not trust the aftermarket OBD stuff deleting the memories correct. There are more things having to be reseted than the error codes, which you device maybe don't do or you have to do it separate- don't know the specs of your device.
Technically you don't even need them.
1. turn the ignition key 3 times in on/off and then let it on- the engine light will flash- it will flash fast for every number- example 3x pause 2x pause 3x pause 4 times pause means 3-2-3-4. this is your P-Code- google will make you find the descritpion. If you have more codes, then all 4-digit codes will come up one after another. write with. if it's ready and no more codes are there, it will end with 4-4-4-4. don't turn the ignition off before.
then there are the readiness codes- these are the learnable codes for the PCM which are individual for every vehicle. the codes are set as you drive and adapting to your habits. If there is something wrong, you also get a engine light.
the most obd- devices delete just the error codes but not the readiness codes. If you disconnect the battery, you delete all codes- error codes and readiness codes. the codes set them self when you drive.
this would explain, that the light stayed on after you deleted the codes with your obd device and stayed off, after yo disconnected the battery- if I understood right.
If the light stays off- be happy
If there is something wrong, the codes or THE code will come back.

have a great day

Chris

 

Thanks for that quick response, and I may not have been clear but the engine light had been on, which is why I used the OBD2 device and btw it is a professional model not that cheap one advertized for 49.95. I bought this one from a mechanic friend who was upgrading his model. But it sounds like disconnecting the battery was the key, lets hope it stays off now and I don't have to crawl under and check the cat temperatures up and down stream to determine if cat is bad. Thanks for your input.

 

The OBD codes did go off after deleting the with obd, but returned, but it must have been the readiness codes , anyway I guess we will see if the engine light stays off, thanks again

 

Unfortunately the code came back, I understand to check the cat I need to use an infra red thermometer and check the upstream against the dowmstream temp of the cat and if the downstream temp is not siginificantly higher the cat is bad. If that is the case, do I need to replace both banks cats ? Or can I just replace the cat that is bad ? Does anyone what after market cat works the best with the 4.7 liter ram.

 

too much effort.
when the vehicle is cold- hit with your fist against the catalytic converter. if it rattles, it' s done. the correct way to check the catalytic converter is, check the CO before Cat and after. Then you will see if it works- everything else is lot of hokus pokus and out of the smoke comes an expensive bill. I worked on cars for over 25 years (7 years ago I was smart enough to find me a office job) and never needed to do such things like temperature measurement on catalytic converters or such stupid stuff like smoke test. this is just money making crap. remove it, check it- there is not much what can break on a catalytic converter.
when the catalytic converter fails to work and is not broken, it needs to be changed- and- most important- checked why. it does not quit working just without a reason.
if it's clogged up, there is a rich combustion for example.
aftermarket catalytic converter work, but they have to have the same volume. normally you get the refurbished catalytic converters, but they are not much cheaper than new ones.
that's all I can tell you from here without seeing the vehicle.

good luck

Chris

 

Chriss thanks for your time, it does seem like I am thinking about this too much. It's just that my instincts say the vehichle runs to good to be a cat, and once you replace it their is no going back. Then I would hate to have spent that money only to find out that as I suspect my down stream sensors are not functioning as they should be. And the funny thing is that the P0420 code Im having is from bank one and the sensor that I am most worried about is the downstream sensor in bank 2, it's not even pulling .500 volts, more like .200 volts. I am one of those folks that doesn't believe everythign I hear, I need several clues before making this kind of change. Yes the light is on , and it does say the catalitic converter is running inefficiently, but if the sensor that is measuring it is working but not working correctly how can I trust the reading. Sorry for wasting your time, but I will check to see if it rattles, that might be the second clue I need. Thanks for your time.

 

Replace the sensor and be done with it.... 9/10 times that code is generated b/c the downstream (post Catalytic Converter) sensor has failed.


You done Hijacking threads now? lol

 

Please start your own Thread next time. Posting in someone else's thread confuses members and reduces the possibility of the original creators problem getting resolved.

I moved all of your hijacked posts into your own thread.

Good Luck

 

Let us know if replacing the sensor helps.

If not the next things to check are the wiring and connector on the truck side of that circuit, and the Cat(s).