OBD 2 codes - PeachParts Mercedes-Benz Forum

sokoloff · #1 02-23-2008, 07:28 PM

My check engine light on the 210 came on today. Code reader showed two stored codes, P0100 for what I figure is the MAF and P0400 which shows up as EGR flow. Could the P0400 be stored in the system since May when I ran the car with the manifold off? I've had no check engine codes since then and I can't recall whether or not I used my code reader to read and/or erase any codes that might have shown up at the time. When I erased both codes today, only the P0100 one showed up again.

I cleaned my MAF the last time this happened about 14 months ago and all has been well until today. Tried cleaning it again today, but wasn't successful on my first attempt.

Anyone using the Pierburg MAF for the CDI's that's been mentioned on here before? The insert only runs about $85 or so.

TMAllison · #2 02-23-2008, 07:41 PM

Len - In my experience with a bad MAF it was VERY evident that a fault was occurring. There would be no turbo boost and it was difficult to get the RPM's over 3k.

If yours doesn't exhibit loss of power, I'd suggest checking the wiring and connections at the MAF. PO100 is a "circuit" malfunction. Its possible the ECU is simply noting a loss of communication occuring.

sokoloff · #3 02-23-2008, 08:32 PM

Terry - I don't recall there being much difference in performance last time the code came up or this time either, although today I only drove about four miles home after it came on. I do seem to think that I felt a little lurch when I think the light first came on. Maybe I'll get a chance tomorrow to air it out a little and see if the performance is down.

sokoloff · #4 02-25-2008, 05:22 PM

Took the car out for the first real drive since the check engine light came on. Light is still on, but it's hard to feel any difference in the car's performance. Still runs well, gets up to speed as before and no rpm limitations of any kind. As I mentioned in my last post, I don't recall there being much difference the last time either. I did buy the CRC MAF cleaner today and will give that a try and reset the codes. I did not reread the codes today. Will do that before I R&R the MAF sensor.

sokoloff · #5 02-27-2008, 03:05 PM

Tried the CRC MAF spray cleaner today. No luck so far shutting off the check engine light. Still showing P0100. It also shows 32.19 lb/min flow at the MAF. I'm not sure how that compares to what it is supposed to be. Anyone know? I'll drive it for a few days and see if the light goes off. I doubt it since the OBD II code reader wouldn't allow me to reset it. Then I'll spring for a new MAF. Again, there's virtually no difference in performance so far.

TMAllison · #6 02-27-2008, 03:17 PM

My generic OBDII scanner can delete that one. Surprised yours is giving you difficulty?

sokoloff · #7 02-27-2008, 08:07 PM

Terry - I probably misspoke. What I mean is that my code reader will erase the code, but by the time I get to look at the light in the car, it is back on and the code reader has picked it up again.

nhdoc · #8 02-27-2008, 09:58 PM

FWIW I got a CEL shortly after I bought my car 3 years ago and it was an MAF fault though I noticed no perceptible difference in the way the car ran at all. I replaced the MAF and cleared the code and it never re-appeared. At that time I didn't know about cleaning them but I can say that some MAF faults must just be enough to trigger the CEL and store a code (like readings outside of expected parameters) and not enough to have an effect on engine performance. I used an aftermarket MAF from Bosch at that time. Might still have the old one too but can't swear to it but if you want to try and borrow it I will look Len.

TMAllison · #9 02-27-2008, 11:42 PM

Len - Here's a MAF test doc I saw on the Tech forum and saved a while back.

The link was not working for me this evening. http://www.x-desk.net/ximages/21302_pgsi0079en.pdf it may be down or broke?

If you copy the file name 21302_pgsi0079en.pdf and search using google you'll get LOTS of info.

sokoloff · #10 02-29-2008, 07:02 AM

Link still not working Terry. Thanks for the offer Doc and thanks for trying Terry. I'm not too concerned about it. I got an extra 14 months out of the MAF after cleaning it. It gave me seven years and 80,000 miles of service, so it's probably just time to go ahead and change it. I was a little concerned about the EGR code showing up, but that must have just been an old stored code. It has not showed up again after I cleared it.

sokoloff · #11 03-09-2008, 01:29 PM

Replaced my MAF today using the one from the CDI mentioned in the first post. A member here has used it successfully for over 50,000 miles and it's recommended on the VW TDI forum. MSRP is $100. It was $85 with my MBCA discount. Light did go out this time with the new MAF. We'll see if it gives me a good 50,000 miles. Photo below shows the old MAF on the left and the new one on the right. Slight difference in the length, but the fit seems exactly the same.

sokoloff · #12 03-09-2008, 04:45 PM

EGR flow is now 1.75 lb/min at the MAF with the new part vs. 32.19 lb/min when the check engine light was on. Anyone know what spec is?

aklim · #13 04-16-2008, 03:04 PM

I replaced a broken MAF with the part and it works better. Not perfect but better. Sometimes it throws a P0100 code especially when I do WOT runs.

aklim · #14 05-20-2008, 11:47 PM

This is what I see. I borrowed an OEM unit and it works just fine. Switched to the "alternative" and once in a while we get the P0100 light. What that tells me is that if you are running a stock PCM, it probably will work. If not, probably not. I have a Speedtuning USA PCM in my car.