2014 1500 4x4 crew cab big horn. Around 34,000 miles. At about 12,000 the CEL went on, went to the dealer, he pulled the code and said it was because the gas cap was not screwed on tight enough. I explained to him that the diesel fuel cap is a plastic plug and did not screw on. He said 'Oh, must be a glitch somewhere', he reset the code and all was fine until about 25,000 miles. CEL comes on again and it was a P20EE. He flashed the ECU, reset the code and I did not even make it home before the CEL came back on. I have an OBD II reader, so, I check it and it was a P20EE again. I reset the code myself and all is well until around 29,000 when it comes back. But, the CEL goes out after about 500 miles, then comes back for a few hundred, then goes back off, ...., then goes back on and has been on for the last 2,000 miles.
So, I take it to yet another dealer, he reflashes the ECU again and the CEL comes back in about 20 miles. I call the dealer from my cell and he says he cannot look at it again until next week. I reply thanks but no thanks.
Now, I am upset.
So, I take it to yet another dealer about an hour and a half from me and he is the only one that actually looked at the DEF injector, sees all sorts of crud, checks the DEF (the fluid itself) and says it is well within tolerance. He cleans the DEF injector, resets the code, drives it for around 100 miles and the P20EE returns. So, he ordered a new cat converter which should arrive tomorrow morning. In the meantime I am driving a loaner 2015 1500 2x4 crew cab, big horn with the hemi in it. It is a nice truck, lots of pep, but the MPG sucks. I get around 19 AVG while my ED was getting in the high 20s consistently.
So, assuming that the new cat fixes it, I think the lesson here is that you need to have your truck serviced by someone who actually knows WTF to check for and DO. All these other dealers just seem to want to get you out the door as quickly as possible and a ECU flash seems to be the answer for everything. If reflashing the ECU is the only thing your dealer is going to do and the CEL comes back, then find another dealer.
The service manager at the new dealership took a genuine interest in my problem; the other ones did not seem to give a twit. He said he has seen a *lot* of issues with the DEF system on the jeep EDs, but only 1 other one on the RAM ED.