ECU - Electronic Control Unit

In terminology of VW-group it's any electronic device, which has been carried out some logic function. Sometimes it looks like nonsens - even simple relay can be called ECU.

The coding of Electronic Control Unit used for explain the ECU where it is and what "neighbours" does it have. Very often on modern cars the coding is crossed with adaptation.

Adaptation of the Electronic Control Unit serves to explain to the ECU with whom and how to talk (If we have started to speak allegories) and serves as storehouse of various adjustable parameters. ( part of memory in the Control Unit which can be changed via internal software )

Measured Values Blocks ( MWB ) – various parameters being inbound or calculated. Considering to value of MWB Electronic Control Unit, trying to "control"... Using of MWB allows you ( if you know the basic parameters ) to find out "close to boundary" or temporarily arising ( intermittent, sporadic ) malfunctions and many other useful things at competent use.


J217 - Automatic gearbox control unit


A - Wiring harness

B - Multi-function switch

C - Connector

D - Automatic gearbox control unit -J217


The automatic gearbox control unit -J217forms one unit together with the hydraulic control unit (valve body with solenoid and pressure control valves) and the multi-function switch -F125 - the so-called mechatronics unit.

The mechatronics is built into the gearbox oil pan.

The control unit itself cannot be replaced separately, only the complete mechatronics unit.


The mechatronics unit is removed and installed according to the Workshop Manual A Repair Group 38.

YZGeneral note

After replacing, the automatic gearbox control unit -J217 must be coded and enabled for the immobilizer.


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