Hello Clever People,

I'm looking for some basic clarification regarding the VAG parts numbering system with relation to retrofitting and upgrading modules.

Obviously the first three characters represent a "family" group. As an example the BCM/CECM on my 2011 Scirocco starts with the part 5K0, a part found on other later PQ35 vehicles like later Mk6 Golfs and Tiguans.

What I'd like to know is what the following six characters define. I'm taking a wild stab in the dark the middle three relate to a component family and/or type and the last three represent a sub-type, with any following letters denoting a specific sub-version. I'm basing this guess on looking at the wiki page for the Polo 6R Cruise Control retrofit, given the family identifier is obvious and the subsequent characters appear to follow the same pattern as with my PQ35 car. Specifically, my BCM has the part number 5K0 937 086 F, while the Polo equivalent part is 6R0 937 08(x).

Am I thinking along the right lines? And, if so, how much consistency is there with the sub-type denomination (Basis, Medium+, Medium++, High+ etc.)? The reason I ask about consistency is if my logic was correct then my car shouldn't support retrofitted Cruise Control given its "937 086" (Medium++) designation, and given the 6R wiki page suggests a "937 087" is required for CC functionality. In spite of all that it most certainly does support CC as I retrofitted it a couple of months back, slip-ring, stalks and coding being the only ingredients necessary. It would seem very logical (and German) to identify parts by function level (086 on a BCM from any vehicle family being better than 084, 087 better than 086 etc.) but this doesn't quite seem to be the case, hence my mild confusion.

OR, is it a case of the component sub-type functionality being dependent on the specific vehicle family, i.e. a PQ35 BCM "086" offers similar functionality to a PQ25 BCM with an "087" designation.

Does this make sense?

Also, in the case of the PQ35 cars, what extra functionality could I expect to see from a higher spec module such as a 5K0 937 087 AC? Does the same logic apply that an 087-designation module will offer extra functionality over an 086 type?

Or should I just stop worrying and learn to love the bomb?

Cheers, DubSteve