Question on 996 DME/ECU and Engine

[bxtech]

Hello all,

Someone told me that on a 996 3.4, the engine and the DME are "matched". The DME must be programmed specifically for that particular engine, and you cannot "mix and match" different DME's and engines. They also told me that if you change the engine, you must have your DME reprogrammed by Porsche. I find this a little hard to believe since the specs for each engine should be the same. Has anyone ever heard of this?? Any input would be appreciated.

Thanks in advance.

[ischmitz]

The DME is "matched" to the other control units in your car. In particular the DME hand-shakes with the immobilizer unit and talks to the alarm unit. You can replace an engine (assuming the new engine is the same type) but you can not mix and match components such as DME and other control units. All control units have the VIN number of the actual car in their permanent memory. To my knowledge all engine sensors and actuators on the 996 engine are dumb - they do not have any VIN-specific information. They simply provide signals to the DME or receive signals.

The issue comes up when someone wants to upgrade from a 3.4 to a 3.6. This is when the DME and sometimes the harness needs to be changed and that causes a rat-tail of other issues.

Ingo

[bxtech]

Thank you Ingo. Good information! This clears up a lot! I really appreciate it!