To remove ECU or ECM from a VW Golf Mk5, Rabbit or Jetta, first you have to take out the wiper arms (see tutorial) and the windshield cowl.
Then you just have to follow 6 simple steps.
– a flat blade screwdriver
– a 13 mm socket and a ratchet
1: remove the hood seal
2. remove the cowl vent grille lifting it up
3. remove the cable
4. remove those two 13 mm screws
5. bent the ECU case and then slide it out
6. disconnect the cables from ECU.
See also these VIDEO TUTORIALS for VW Golf Mk5: