In recent days, several Audi vehicles have come into the shop, all displaying the warning “Battery Voltage Low.”
The car owners initially thought, “It’s fine, we can still drive!” But as they drove, the car suddenly broke down and turned into an electric deadweight! Time to call a tow truck!
Using a diagnostic tool, the fault code “Generator Control Unit, Signal Unreliable” was found, with both static and intermittent issues.
Using a multimeter, it was found that the generator was not generating power. However, as mechanics, we need solid evidence; we can’t easily declare the generator dead!
The crucial step is here: first, upgrade the generator control unit to the latest version. If the fault code persists after the upgrade, then it’s confirmed—the generator is indeed dead!
These delicate generators are all installed on the EA839 engine, which is a 48V starter-generator. It can function as both a starter and a generator, sounds pretty high-tech, right? But its price is even more high-tech! Imported from Hungary, over 20,000 each.
Upon disassembly, the circuit board was burned, which is a classic failure mode.
It must be said, this thing is both expensive and fragile. Is it really an environmentally friendly black technology, or just Audi’s financial product? The 48V mild hybrid claims to save fuel, but how many years of fuel can one repair cover?