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U16D300 — High voltage charger, pre-charging not successful

High voltage charger, pre-charging not successful. The Taycan, Panamera (971), Panamera (972) and Cayenne report this code; below is which control unit sets it on each model and how to read and clear it.

Which models and control units set U16D300

Porsche Taycan

Porsche Panamera (971, 2017–2023)

Porsche Panamera (972, 2024–)

Porsche Cayenne (9YA)

How to read and clear U16D300

  1. Plug a standard ENET (Ethernet-to-OBD) cable into your Porsche's OBD port and your Mac or Windows PC.
  2. Open STEUER14, pick your car and run a fault scan: every control unit is read, and U16D300 shows with its status, its full description and the freeze frame when the unit stores one.
  3. Fix the cause first, then clear the fault memory and scan again to check it stays away. Reading and clearing fault codes is free on every control unit.

More about fault memory in the manual →

Download STEUER14 — free fault reading

Other codes of the On-Board Charger 2

U112200Data bus - implausible message
U112300Data bus – fault value received
U13AE00Active parking system control unit – fault detected
U140000Function restriction – supply voltage too low
U140100Function restriction – supply voltage too high
U140900Internal temperature measurement, Implausible signal
U300100Control unit – run-on fault

All 110 codes of this control unit →

Fault names come from the manufacturer's diagnostic data. STEUER14 is independent and not affiliated with Porsche AG. A code tells you what a control unit detected, not always which part failed — check wiring, supply voltage and related codes before replacing parts. STEUER14 shows each fault's full description, status and freeze frame on the car.