I'm getting these cel's
17521 - Oxygen (Lambda) Sensor; B1 S1: Internal Resistance too High
P1113 - 35-10 - - - Intermittent
16486 - Mass Air Flow Sensor (G70): Signal too Low
P0102 - 35-00 - -
Readiness: 0010 0101


Icleared them and the O2 hasnt come back yet (3 days)but the mafcame upas soon as i turned the car on, off, then on again. Could the maf code be because ofthe O2 code, or O2 because of maf?Looking online to buy a replacement maf sensori havent been able to find the correct one. The part # is 0 280 218 038, and it didnt show up on any of the sites i looked at or ebay. Anyone know a place besides a dealer?Any helpis greatly appreciated.

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2000 A6 2.7t 6sp. Bose, Cold, Conv.

I once got the MAF code, just used some isopropyl alcohol 99.9 on aswab and cleaned the wire mesh on MAF sensor gently, so far havent seen code again and car idles much smoother than before

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2001 A6 2.7T BITURBO QTRO-Silver Bird

The O2 code is most likely because of the MAF sensor malfunctioning, but even more likely they are both bad because the O2 fault is an internal resistance fault indicating the sensor is bad.
Clean the MAF, clear the fault and see what happens.

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00 A4 1.8T

01 S4 for sale, PM for details.

I spent some time cleaning the maf sensor last night and still got the same cel after runningmy carfor a few mins. Is there some special way to clean it, or hidden parts i might have missed? I really want it to start working but am now doubtful, since the light came on its read .25 g/s no matter the throttle position. Does anyone know where I could buy another one? I still havent found one on eBay or any other sites, The part # is listed in the first post. I'm guessing I could call a dealer or shop but that would probably cost $200 or more.

One more thing, the O2 code hasnt come back yet and its been about a week, not sure what to think of that. Thanks ahead of time for any responses.

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2000 A6 2.7t 6sp. Bose, Cold, Conv.

I just experienced the same thing...CEL from MAS I purchased one from a dealer and had shipped overnight for $160...picking up and installing this afternoon then hopefully the CEL will disappear for good. Wish me luck.