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C123B01 — Front marker light – electrical fault
Front marker light – electrical fault. 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 C123B01
How to read and clear C123B01
- 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 C123B01 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 Light Control Left
| C123AF2 | Daytime running / marker light - voltage too high |
| C123AF3 | Daytime running / marker light – voltage too low |
| C123AF7 | Bulb for daytime running light & park. light, Overtemperature protection active |
| C123AFA | Daytime running lights/marker light, above normal temperature |
| C123AFB | Daytime running / marker light – short circuit |
| C123AFC | Daytime running lights/marker light, below normal temperature |
| C123B13 | Front marker light – open circuit |
| C123BF0 | Front marker light, coding resistance – electrical fault |
| C123BF1 | Front marker light, temperature sensor – electrical fault |
| C123BF2 | Front marker light – voltage too high |
| C123BF3 | Front marker light – voltage too low |
| C123BF7 | Bulb for parking light, Overtemperature protection active |
All 223 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.