2013 F-250 (6.2L GAS) P0420 & P0430 CAT Codes

the_twig_187 · January 19, 2018

Hey guys

I have a 2013 F-250 (6.2L gas) with 160,000km. Came in check engine light on, scanned it and found P0420 & P0430 CAT efficiency codes on both banks. Viewing the PID data on the scan tool im used to comparing the voltage switching from the pre and post cat o2 sensors but this system uses a UEGO sensor for the pre cat sensor and thus cannot be interpreted in the same was as a conventional o2 sensor. The post cat o2 sensor data shows the voltage constantly changing up and down (which would normally indicate that it is mirroring the pre cat o2 and would lead towards a bad cat) but im not sure how to interpret this on a system that uses EUGO o2 sensors?

Anyone have any help? Always greatly appreciated

Chris

tonybullitt · January 20, 2018

Switching down stream sensors indicate failed cats for sure. On the Uego sensors watch the a/f ratio pids. Just have to remember 14.7 to 1 is ideal. Uego sensor are just air fuel ratio sensors

JoeR · January 21, 2018

If your fuel trims are good, and the rear O2s are switching, then it sure sounds like bad cats to me. That's kind of an early age to die though. It makes me wonder what murdered them.

Joe

the_twig_187 · January 22, 2018

Yah thanks guys, I have a ton of conflicting evidence that I have read on the net (not at a ford dealer anymore...no ids/oasis ect...) I have a snapon solus edge scan tool that I purchased less than a year ago (its no IDS but I paid almost 5 grand for the thing, it works pretty good). The vehicle is the only flex fuel vehicle in our fleet and the problem seems to only happen when the truck drives with a trailer. I read online (I know lol reader be-ware) that sometimes the flex fuel vehicle will get sketchy when adding a trailer and the pcm infers the added load pull as E85 (flex fuel learned). Don't know what to think about that? Also read some articles saying that the plugs can foul early and cause an incomplete (fuel saturated) burn to fuel soak the cats. Don't know what to think about that either.

All and all I just don't want to tell management that $2,500 worth of CAT's is needed only to have the CEL return when pulling a trailer again, and maybe all it needed was a PCM update (which I cannot do and must send to a dealer to perform)

I cleared the check engine light, reset KAM and ran the vehicle, the downstream o2 voltage on both banks is switching up and down (at idol) just like a conventional upstream o2 would, and is not a close to constant flat line like I would expect it to be. That's the only thing leading to me saying bad CATS. Just very suspicious that this vehicle is our only flexfuel and by far is the lowest mileage and newest 6.2L vehicle we have and it managed to smoke both CATS and non of the others did??? I DUNNO???

tonybullitt · January 22, 2018

Do you know history on this truck? Your cats are junk but why is the bigger question. We have a lot of issues with evap purge valves and on a flex fuel vehicle they wont set codes a lot of times because the pcm just assumes it needs to adjust for different fuel. It would be a good ideal to get the truck reprogramed.

the_twig_187 · January 22, 2018

My theory of "WHY" the CATS failed is...The vehicle drove without a trailer for a long time. PCM learned all non-trailer driving values. Then truck drove with a heavy trailer, the added weight caused the irregular load on the engine and the PCM inferred this as e85 (hence the flexfuel learned = yes PID) and compensated by adding more fuel as per the E85 fueling strategy. This rich fuel trim then saturated the CATS with fuel and caused them to fail.

This of course is only a theory and I do not know what actually happened but im doing the best I can with the resources and information available to me.

As far as vehicle history goes...nothing except basic maintenance and safety repairs have been performed on this vehicle.

8WA Sman · January 22, 2018

Does the FF inferred pid match what fuel is in the tank? I am pretty sure FF learned pid basically means the PCM has learned the alcohol content.

See if you can get your hands on GSB G0000017 or GSB G0000079 for more info.

I would think in your theroy the fuel trims would still show something amiss.

Does the mode 6 data show by how much the cats are failing or any misfires?

the_twig_187 · January 26, 2018

Well I don't know whats going on with this thing, but I cleared the codes and reset KAM. Went for a test drive and all seems well. Short and long term fuel trims are showing properly and the downstream o2's are also displaying a flatline voltage value (more like what we should be seeing with a downstream signal). Driver has been driving the truck for about a week now (without pulling a trailer) and he said all is well and no check engine lights. Not sure whats going on when he pulls a trailer but for now it looks like its ok.