benmarks
Veteran Member
You may be wondering why I am posting an image of my cluster. Finally as of today, my 4Motion is working and this is my first error-free cluster!
However, this post is for anyone else who might be considering a 4Motion retrofit, or has already done one but had to use a manual switch to get all wheel drive to activate. Since March when all the body work was done and we moved to the electrical stuff, we hadn't been able to get the ECU and ABS module to communicate properly. We finally discovered the issue which I think may not be well known among people who are doing this mod.
In order for our cars to be retrofitted (properly) with 4Motion, you need some extra parts that don't necessarily come with the backend kits you'd purchase from Korwerks, et. al.
ABS Module: 1C0907375P or 1C0907379P, you might see it sold with either number, but it's the same part whether it's a US R32 or a Euro 4Motion Bora/Golf
Rear ABS Sensors: 1J0927807D x 2, 4Motion-specific
G251 Module on Steering Column: 1J1907638F, this is the 3-sensor version of this module which has yaw, longitudinal speed and latitudinal speed sensors
Once you have all of these parts, and once you calibrate them, you will still be confronted with an issue. Even though you can repeatedly re-code the 4Motion ABS module with the correct code, an error will always return after you clear the codes stating that the ABS module is coded incorrectly. This is where we got hung up and what we finally fixed today. I hadn't seen this info anywhere else, and none of the other people that I could find who'd done this retrofit had known it either (at least in the context of the retrofit.)
An old forum member in Australia named Graeme (whose R32 has been the inspiration for many of my mods) discovered an ancient 2008 Vortex thread from an R32 user who'd swapped his engine and ECU with ones from a TT. It wasn't apples to apples with my project, but it was the clue we needed. I was then able to find wiring diagrams for the ABS module connector in the engine bay. The ABS module connector is identical on a Jetta and an R32, except for a single jumper wire. On a 4Motion Jetta and the R32, there is a jumper wire between pins 14 and 39. On a front wheel drive Jetta, there is also a jumper wire, but it is between pins 12 and 38. I was worried there would be more differences between the wiring diagrams, but apparently this is the only difference. The ECU performs a check, and if the version of the ABS module (4Motion or FWD) doesn't match the jumper wire, then the error code is triggered.
As soon as we moved the jumper wired and cleared the codes, everything started working!
So, for anyone who's done a 4Motion retrofit but who ended up using a manual switch for all wheel drive, this info should help you get 4Motion to work like it did from the factory.
