Tip from the tow bar coding specialist

Beware of an Erich Jaeger e-Set for towbar lighting

Coding a vehicle after a towbar has been fitted is a specialist job. That specialism comes into play when fault codes are still present in the vehicle after the coding work has been done. We at Jifeline Remote Diagnostics regularly watch live in vehicles where, after the correct towbar coding has been done, the fitting company is still left with all kinds of error codes, sometimes accompanied by warnings in the instrument cluster, for example.


Erich Jaeger (of Trail-Tec)

In the case where an Erich Jaeger (or Trail-Tec wiring kit) is fitted, you will find a kind of loop in the wiring harness near the trailer module, see I and J in the image above. This loop contains a plug. The cable loop has the following function:

  • Loop interrupted -> active trailer module
  • Loop shorted -> passive trailer module, no support for vehicle systems such as PDC shutdown, etc.

The installer should check the following:

  • Check That the cable loop, near the trailer module, has been interrupted for an active trailer module

Another common assembly error on Volkswagen group vehicles we explain on this page.

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