RMS Diagnostics tackles an intermittent charging fault on a 2016 VW Transporter that persisted despite previous garages fitting two replacement alternators and a new battery.
Scanning the vehicle with a Thinkcar Euro 399 revealed fault code 02252 for generator communication in the battery regulation module, alongside a fuel temperature sensor fault triggering a DPF light.
After consulting factory wiring diagrams, the team mapped the LIN bus network connecting the Body Control Module, battery monitor, and generator. Back-probing with an oscilloscope confirmed a valid signal at the battery monitor, but a total signal drop at the alternator.
Inspecting the wiring loom beneath the undertray revealed a broken signal wire. Cleaning corroded terminals on the fuel temperature plug corrected live data readings, while soldering and heat-shrinking the severed LIN wire fully restored generator communication.
