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B12BC13 — Left rear side marker lamp bulb, Open circuit

Left rear side marker lamp bulb, Open circuit. 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 B12BC13

Porsche Taycan

Porsche 911 (992)

Porsche Panamera (971, 2017–2023)

Porsche Panamera (972, 2024–)

Porsche Cayenne (9YA)

How to read and clear B12BC13

  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 B12BC13 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 Comfort System Module

B122313Rear wiper motor – open circuit
B126301Filler flap lock motor – electrical fault while unlocking
B126511Rear window heating relay – short circuit to ground
B126515Rear window heating relay – short circuit to B+ or open circuit
B12BC11Left rear side marker lamp bulb, Short circuit to ground
B12BC12Left rear side marker lamp bulb, Short circuit to B+
B12BC15Left rear side marker lamp bulb, Open circuit/short circuit to B+
B12BD11Right rear side marker lamp bulb, Short circuit to ground
B12BD12Right rear side marker lamp bulb, Short circuit to B+
B12BD13Right rear side marker lamp bulb, Open circuit
B12BD15Right rear side marker lamp bulb, Open circuit/short circuit to B+
B12BE11Outer left rear marker light – short circuit to ground

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.