New to this forum, so please be patient as I learn to navigate. I recently bought a 2011 Bluetec from a friend. Awesome condition with 125k miles. The check engine light had been on with the code for the Particulate filter high in soot etc etc...before I purchased my friend had the mechanic take a look and determined the filter needed to be cleaned. Filter was cleaned and the check engine light back on few days later. So, sensors for the filter were replaced and a day later the check engine light came on the day after I purchased. My luck. So, instead of taking it to the mechanic they had used, I took to another European mechanic. They went through the entire car. Def tank in back is heating, they did manual regeneration, replaced the turbo sensor, and even reset the ECM, checked for leaks and found nothing. Check engine light is STILL on.

Since the sensor and the filter have been cleaned why the heck is this check engine light still on and the car continues to go into Limp mode??? What else could this be?

Any tips would be so appreciated. I’m out $500 just trying to figure this out already.

 

Welcome! Please post a photo of the GL. The X164 and diesel sections of the site have many helpful owners who can guide you.

 

Welcome to German cars and diesels with SCR systems in general.
I'm fairly new to Mercedes but have over 25 years of BMW's, including an X5 diesel I wish I had kept.
If the Mercedes is like the typical BMW, scanning for codes with a brand specific scanner, resetting them, driving for a few miles to see what comes back is step 1 and will determine the next step.
So with what you posted, what code(s) is still present and triggering the CEL?

You also say they cleaned the filter and replaced the sensors. Did they remove the DPF for cleaning or just inject snake oil in it? What sensors? NOx sensors? If they removed and cleaned the PDF and put in new NOx sensors for $500, that is a steal...

A couple of thoughts based on BMW diesel experience.
1. The filter was cleaned. What method?
2. What is the current ash mass vs. max for that filter after it was cleaned? If ash mass is still above the point that triggers a CEL, then the cleaning did not accomplish the goal.
3. After cleaning or replacing the DPF, does Mercedes require a reset of some kind to tell the car to reset the ash mass / other values? Would have to have access to repair procedures to determine and I'm not familiar enough with this car to tell you but someone else here may know.
4. They forced a regen but are all the conditions met for a self regen? For instance, on the X5, the thermostats soft fail whereby coolant temp does not get high enough to trigger a regen. You then end up chasing DPF related codes and replacing DPF, NOx sensors, EGR at great expense when all you really need is a new thermostat. I'm not saying this is what is happening, but the lesson here is that you need to work with a shop that can get to root cause and not just keep replacing parts until they find the right one.
5. These types of issues are the reasons why many people will do an alphabet delete - meaning they delete all the emissions garbage (SRC, DPF, EGR) that tends to become problematic and expensive. That is only possible if there are no emissions checks where you live for as long as you plan on owning it and your clean diesel just became a dirty one.

Hopefully your friend gave you a good deal. My 2011 GL, albeit with 175k miles, was given to me by a friend. She couldn't take it any more. Dealer would not take it on trade and she was sending it to the crusher. I'm still pealing through the onion of issues and have not reached the limit I gave myself before throwing in the towel and selling it.

 

Odds are the friend sold to you because it was very problematic for them but this is only speculation. If it is not too late, I would ask for your money back unless you basically got it for free like the above poster. The OM642 in the Bluetec GL's can be extremely expensive to own and maintain. Unless you are absolutely in love with the GL, can turn wrenches yourself, and or are prepared to spend double what it is worth, you should probably sell quickly.

 

So no matter how much you clean the DPF the check engine light won't go away until you use Xentry or reset Adaptations. I had cleaned my DPF 3 times and checked the flow and etc.. It wasn't until I did the DPF adaptations that it went away. You can check my posts to see my history on this issue.

 

Clear CEL with DAS, check DPF pressure sensor, use Amsoil Dominator 20W50