To start off, im not new to the auto tech world, so I know my way around a car, but im coming here because I've asked around as well as attempted myself to diagnose and havent been able to with the ongoing issue.

Ok so im having code(s) pop up which are:

1. Turbocharger/supercharger boost sensor A circuit low

2. Turbocharger/supercharger boost sensor A circuit high (simultaneously with low sometimes)

3. System too rich bank 1

4. Mass or volume air flow sensor 'A' circuit range/ performance (main persistent code)

What I've done so far to diagnose:

1. Multiple smoke tests through airbox, before MAF, after MAF(no leaks found)

2. Checked MAF, replaced MAF twice in hopes of it being a cheap one

3. Installed an OEM CAT from a different C230 from same year paired with new O2's

4. Checked all engine wiring and grounds for shorts and/or cuts or disintegration

5. Checked all hoses and replaced crumbling ones

6. Cleaned bypass circulation valve (secondary A.I.R. pump) as well as throttle body and all sensors regarding air (barometric sensor, intake manifold sensor, throttle body sensor) as well as the throttle body itself.

7. Replaced valve cover and spark plug gasket, as well as made sure spark plugs are dry (new spark plugs installed when I bought the car which was a month or two prior)

8. PCV on the valve cover has been cleaned as well (valve cover was replaced in 2020 as noted by a sticker on the cover)

9. Reset all A/F values in hopes of the car being able to retune and adjust with the new components (no luck, recurring codes still come back)

10. Checked all fuses and cleaned the fuse box/ CAN bus as well as connection to the ECU.

11. New battery (voltages are good and dont drop, plus no parasitic draw verified)

Probably more im missing, but I labeled the major things I've done. Another code I found using a different more expensive scanner (Snap-on) was a CAN bus fault which is was prompted me to check my CAN bus for any issues and it turned out to be surprisingly clean.

Ive also verified values using my MaxiCheck autel scanner with live data and found all values to be within range apart from idle intake maifold pressure as well as intermittent OL-fault in the fuel pump which im sure is attuned to the air issue sending data to the fuel pump. Injectors are good, same with fuel pump and all wiring. I also double checked values with a multimeter.

also some of my monitors are showing as incomplete which is preventing me from getting SMOG done. The monitors that say Incomplete are there and are showing values + verified with multimeter that they are working and are in spec.


I need pointers and what I should do next. I can provide any logs, values or anything pertaining to this issue so that I can hopefully fix and provide a fix for others with the same issues. I can provide pictures and update the post as needed.

 

Have you checked the MAP sensor?

 

I'm guessing from the code desciption these are OBBII and not Mercedes codes?
If so, it would GREATLY behoove you to invest in a scanner that readss MB codes.
Compared to your parts cannon, it is much less expensive.
As far as suggestions, I'm not the best person to ask.,
I have an iCarsoft. It sucks for so many reasons.
I now have the Launch Elite blah blah better but not as good as I'd have liked.
No support and using the programming functions can brick the ECU.
A lot of people mention Autel but I'm not sure which one.
I might sell both my scanner and buy one.