2.5 TDI confusion over engine type (BAU or AKE)?


Registered User

I have a 2004 2.5 TDI A6 Avant Quattro 180hp. The label in the wheel well says the engine is BAU type. VCDS software says it’s an AKE. How do I physically tell what engine it is?



Staff member
VCDS Map User
It may have been remapped at some time with an AKE file written to the ECU or the ECU has been changed. If you look on the V5 document this will have the engine serial number and this should be the 3 digit engine code with a number following it.
It's possible the original engine has been replaced as the 2.5 TDI engines had issues with hollow cams that would snap and this basically trashed the engine.
On this ad for a BAU engine there is a picture of the serial number. See if you can locate this pipe on your engine you will then find the engine serial number.


Registered User
Thank you. You hit the nail on the head.
It’s marked on the block and V5 as being a BAU. As you say the ECU software must have overwritten with AKE version.


Registered User
So, does this mean the two engines will fit in either car? I have a bau for spares, my car is ake, and I cannot see any differences except in the plug and belt for the air con pump. The engine, and its pump are for sale, along with the majority of the rest of the car


Registered User
i have the same. VCDS says its AKE but its supposed to be BAU.
maybe vcds doesnt differentiate?