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B16D404 — Outer left tail light – defective
Outer left tail light – defective. The Taycan, 911 (992), 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 B16D404
How to read and clear B16D404
- Plug a standard ENET (Ethernet-to-OBD) cable into your Porsche's OBD port and your Mac or Windows PC.
- Open STEUER14, pick your car and run a fault scan: every control unit is read, and B16D404 shows with its status, its full description and the freeze frame when the unit stores one.
- 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 readingOther codes of the Comfort System Module
| B16C315 | Left tail lamp, Open circuit/short circuit to B+ |
| B16C404 | Right tail lamp, faulty |
| B16C411 | Right tail lamp, Short circuit to Ground (GND) |
| B16C412 | Right tail lamp, Short circuit to B+ |
| B16C413 | Right tail lamp, Open circuit |
| B16C415 | Right tail lamp, Open circuit/short circuit to B+ |
| B16D411 | Outer left tail light – short circuit to ground |
| B16D412 | Outer left tail light – short circuit to B+ |
| B16D413 | Outer left tail light – open circuit |
| B16D415 | Outer left tail light – short circuit to B+ or open circuit |
| B16D416 | Outer left tail light, voltage too low |
| B16D417 | Outer left tail light, voltage too high |
All 616 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.