(Too Long Didn’t Read at the end)
My father owns a 2018 Mercedes Sprinter 2500 with 48k miles and it is an automatic. He uses it for A/C work but it quit working on him. The computer screen on the dash told him to “add DEF” and limited the number of times to start the engine. He returns home and adds the Def but the limited amount of starts notice persists. So he continues working and uses the last start to get back home and now it is in idle mode and won’t travel faster than 5 mph. So I look into it. I purchased a Topdon Antidiag OBDII scanner to read the codes and here they are as follows: P19DE, P186A, P16CF, P1067, P178F, P1790, P19A3, P19A4, P19A5. Based off the descriptions and searching up some of these codes, I was led to believe there is something wrong with the Adblue/Def injection/exhaust after treatment system. After watching some helpful videos I replaced the Up and Down stream NOx Sensors as well as I cleaned the crystallized Def off of the Def injector. After all of that the truck is still stuck in idle mode and the codes won’t clear. I believe the codes are permanent codes but to clear those the truck would have to go through a couple of drive cycles which I cannot complete due to it being stuck in idle mode. I’m stuck out of options and we are ready to hand it over to the dealer although I have a sneaking suspicion that the main computer module is broken/faulty because prior to these issues he noticed some clucking with the engine/transmission in mid gear. Any info or help is greatly appreciated!
(TL;DR) 2018 Mercedes Sprinter 2500 with 48k miles is stuck in idle mode gives the following codes: P19DE, P186A, P16CF, P1067, P178F, P1790, P19A3, P19A4, P19A5. Replaced both NOx sensors and cleaned DEF injector but codes won’t clear and truck is still stuck in idle mode. Any info or help is greatly appreciated!
It has to be towed to dealership. The van locked itself out and they have to reset it. Usually when something like this happens with the def run the cleaner and purge the system. Then do a force regeneration then top it off the fluid. Reset the codes and you should be good. You need a scan tool that can do all that. .
Thanks for the advice. For future reference, is there a certain Dpf cleaner you prefer to use? Also will that cleaner also clean the Def injector because when I took the injector off, there was a bunch of crystallized Def blocking the injector.
Also one last question, would that Dpf cleaner clean the NOx sensors or is there something else I have to do to maintain those sensors?
Liqui moly diesel additive, Liqui moly diesel particular filter cleaner and liqui moly DPF purge fluid . I don't work on diesel often but I always stick with liqui moly. I have heard bluedef platinum is really good as well.
As for the nox, Im not to sure about cleaning them. That's something I've never done or tired , I have heard or people soaking it for a few hours in diesel fuel system cleaner or Lucas then blowing it out with compressed air.
For the def injector sometimes you can get away with a fuel additive. Some people use steam or water and a soft tooth brush. Others will just replace it.
Couple times I've done it I used steam and a really soft brush.
I asked a friend if he had or knows off any dpf videos for cleaning / purging and sent me this. Guy actually uses the same stuff I
use and recommend.
I will use this on the future, thank you.
It's a Mercedes. Not very DIY friendly.
Yeah we thought as much but we didn’t think it was going to be this bad to the point only the dealership can fix it.
Merc absolutely LOVES to computerize every little thing, including the brakes. Hundreds of modules everywhere.
