# audi allroad 2.7t misfire codes.....



## scir036trs (May 9, 2007)

so im new this whole vag-com, b4 my audi my newest ride is a 81 sportruck....
anyway, went for a drive over the nearest pass around 150 miles.... 
under a load and driving about 65-70 is where the misfire started
near the end of the trip, misfires were more freq. after updating my software, i pulled some codes they are as follows....
any help would be great! Im assuming coilpacks? but may be wrong....
16684 - Random/Multiple Cylinder Misfire Detected 
P0300 - 35-00 - - 
16688 - Cylinder 4: Misfire Detected 
P0304 - 35-00 - - 
thanks for your help!
...
an 81 rabbit doesnt do this


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## v b chil-n (Nov 6, 2000)

*Re: audi allroad 2.7t misfire codes..... (scir036trs)*

Boy does that look familiar.. 
Try this, swap the cables that run to the POS 's on the air box and see if the misfire switches cylinders.. if it does you have a bad POS if not it might just be a bad coil or plug.


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## Mr.Timewise (Feb 3, 2010)

*Re: audi allroad 2.7t misfire codes..... (scir036trs)*

I've got the same problem...and had it once previously.
In my case it turned out to be one of the two ignition control modules (a.k.a. ignition control unit) on top of the air intake referred to by "v b chil-n". This is Audi's part number 4A0 905 351A, or Bosch's p/n 0227100209. Use all the characters when doing a search, as there has been confusion with a ICM without the last letter "A"..
eBay has several sellers. I bought used ones, but be aware that the underside of the module needs to be very clean and smooth, and will require a coating of thermal paste to allow the heat inside the module to be removed. New ICM's come with a small vial of this paste.
Determining which of the two module is defective is difficult because it is nearly impossible to follow the wiring. I was lucky when my first module went bad, as I had an A6 2.7T in addition to the allroad 2.7T. I just swapped modules between cars to determine which one caused the problem.
My allroad is now showing signs of cylinders 4 and 6 as being problematic. And now my A6 is gone. So if anyone can tell me which of the two ICMs connects to cylinder bank "2,4,6" please do so.


_Modified by Mr.Timewise at 1:26 PM 4-27-2010_


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## v b chil-n (Nov 6, 2000)

*Re: audi allroad 2.7t misfire codes..... (Mr.Timewise)*

Black connector is cyl 1,2,3. Brown connector is cyl 4,5,6


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## Mr.Timewise (Feb 3, 2010)

*Re: audi allroad 2.7t misfire codes..... (v b chil-n)*

Thanks. I do remember that the connectors have a certain "tint" under the coating of dust and dirt.
Oh...and I see that my numbering sequence was all screwy.










_Modified by Mr.Timewise at 7:09 PM 4-27-2010_


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## scir036trs (May 9, 2007)

*Re: audi allroad 2.7t misfire codes..... (Mr.Timewise)*

thanks guys this is going to help!


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## Mr.Timewise (Feb 3, 2010)

OK...one year minus three days later and cylinder 1 was reporting misfires after the car sat with the engine warm. Fortunately I had a spare ICM. I replaced the ICM closer to the passenger compartment (the one with the black connectors) and cleared the codes. All is good again!

The codes I had were:

16684 - Random Misfires
P0300- 35-00
16685 - Cylinder 1 Misfires Detected
P0301-35-00


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