I'm being driven crazy here.

TL/DR version: CEL appeared, 2007 E320 Bluetec entered limp mode. Entry level scanner said P0101. I replaced MAF sensors, cleared codes, no improvement. I replaced the orange gasket between the batwing and the turbo, with no improvement. I hunted for and found a leak in an intercooler hose. Replaced the hose, car ran great, still had the same P0101 even though I had "cleared it" with my entry level scanner. I then went back to the original OEM (Bosch) MAF sensors...since at that point I reasoned the leaky intercooler hose was the fault, and not the MAF sensors themselves.

For Christmas I received an Autel MD806. It could drill down and re-interpret the P0101 code as a P2633 code ("Mass air flow sensor Sensor drift Offset drift under engine load. The limit value of load point 2 has been exceeded").

I have tried repeatedly to clear that code. I have left the battery disconnected overnight (having previously depressed the brake pedal to discharge any remaining charge). If I stop and immediately restart the car after clearing the code for as many as ten cycles, the CEL won't appear on the dashboard. But if I wait even 60 seconds before restarting the ignition, the code immediately appears. When I run my scanner I can immediately see the same P2633 code as pending--even if I haven't restarted the engine since the most recent time I cleared it.

In other words, I don't think my Autel MD806 is clearing the code. (As further evidence, I have included the screenshots of the saved FFD info, which seems to indicate that it is a very old infraction, indeed, since it happened at 18,000 km (and the car now has over 200,000 miles on it.)

I read elsewhere (from a post by ) that I have to use Xentry/DAS to ask the ECU to "relearn" the "new" MAF sensors.

So, my following questions:

1) Short of a $1000+ Xentry/DAS system, what is the best scanner for resetting the MAF sensors (which I learned is also called "Reset values for HFM Drift Compensation," thanks to user Regnillub.)?

2) Can my Autel MD806 do it? If so, why can't I seem to find the proper menu to do so?

3) Is it possible that exchanging the MAF sensors (having blasted them with MAF cleaner) is confounding things? In other words, should I try to exchange their present positions, just on the off chance that I mistakenly exchanged positions during the time I was running "new" MAF sensors and when I replaced them with the originals? (To reiterate: the car is running fine; it just throws a code which means I can't pass smog.)

4) If I have to employ Xentry/DAS, does anybody in the Anaheim (Southern California) area have a recommendation for an indy shop (or Benz owner/enthusiast) who will reset the MAF for me? I am loathe to drive to the dealership or a regular shop because I am all but sure they will look under the hood, see my batwing with aftermarket reinforcements (something I tried on a lark after the new gasket didn't offer any improvement), and immediately surmise that the first item of business is to install a new batwing. That I replaced the MAF sensors myself will surely not impress them, since I know they would rather put in a new, OEM batwing (and sensors) than deal with some user-provided nonsense.

Thanks!!

P2633

Frequency Counter: 1, which happened over 200,000 km ago

 

I bought the Foxwell 530 scanner with the MB software and was able to reset the MAF sensor. Foxwell calls the MAF (Mass Air Flow) sensor a HFM (Hot Film (Air) Mass) sensor.

I'd be happy to let anybody in Southern California hook their car up to my Foxwell scanner. If it saves anybody a trip to the dealership, I will be thrilled.