Hi, gang! First time poster, long time lurker.
I've had this 2009 ML320 Bluetec since fall 2018 and have loved it. Gets 20-22mpg in the city!
About 6 weeks ago a CEL showed up so I put my BlueDriver OBD on it and it yielded a broad and vague code that pushed me to buy an iCarsoft. It shows 150200.
Long story short, in this order, I've done the following:
Replaced the y pipe, with new MAFs included. There was a crack in the coupler where it joins to the turbo housing.
Replaced the bleeder valve as there was oil inside the y pipe where the rubber gasket from the bleeder valve joins.
Replaced the air filters with Mann brand units.
Tested the MAF voltage before and after replacement. Both are 14.18V.
Checked battery and alternator performance. Battery is low, 12.17V at cold, alternator is pushing 14V.

At each turn, the CEL will clear with the icarsoft the first time I restart and then returns immediately on the next startup. I'm about to change the oil and replace the battery as part of scheduled/preventative maintenance and would like to know where to go next. I see that other posts around here go so far as to explore the possibility that the code is a "hard code" and will require xentry to clear. Others have said that you need to ensure that new oil levels never exceed 2/3 of the fill level on the dipstick.

Where should I go next??? Thanks for your eyes and your time!

 

you wasted time and money on S diagnostic tool. If you want to solve your issue get a factory or equal scan and return the carsoft crap

 

Thanks for responding. Can you be more specific about what you think I need? And what will they do that icarsoft won't? I've had success with the icarsoft showing codes in real time, specifically the MAFs as I tested the voltage, and it cleared those no problem.

 

What module was this 150200 stored in?

 

You can check here:

https://mbworld.org/forums/m-class-w...f-sensors.html

Or maybe you can take the advice about not using generic diag system on Mercedes. At your model, a reset of adaptation values for HFM is mandatory, after a repair. Not to mention about resetting the adaption values after Air Filters exchange.


My professional advice, use a specialized workshop for a correct maintenance, including parameters reset.

 

It's stored in the ECM, per the icarsoft.

 

Thanks a lot for the response! I had seen that one and it motivated me to swap filters and make sure the bleeder valve was doing it's job. However, that post didn't mention any resetting of the adaptations. Is an air filter job really the delineator for a thorough diagnostics adjustment?

 

Regarding Air filter replacement resetting adaptation values, Xentry ( the official diagnose system from MB) state " must be done".
Also, any trained technicians knows that after any repairs at air intake, the HFM need to be reseted.

 

You didn't mention what çode150200 means. How are we supposed to know, you're the one with the scan tool. And yes, replacement of air filters on this engine requires resetting of the appropriate learned values. Replacement interval is every 30k miles I believe.

 

https://workshop-manuals.com/mercede...33-001_stored/

 

There's so much spam on that page I could barely look at it....looks like digital vomit!

 

Sorry, is not mine...


To answer you, "Upper limits value components HFM SFi has been exceeded"

 

Lots to read when Google searching that code. First you'll need to reset MAF drift compensation AND air filter values, otherwise you're pissing in the wind at this point. If that doesn't work you'll need to continue diagnosis or pay someone else with knowledge and a factory equivalent diagnostic computer, if you can find some place who will work on these old diesels, they can be a nightmare fyi.

 

Now I see, that's "old", I was mistaken by the "Bluetec".

@E55Greasemonkey is 100% accurate.

 

Apologies. Code 150200 "Upper limits value components HFM SFi has been exceeded."