Home › Fault codes › B174C21
B174C21 — Center air vent cover motor, lower limit not reached
Center air vent cover motor, lower limit not reached. 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 B174C21
How to read and clear B174C21
- 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 B174C21 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 Central Electrics
| B174B22 | Left air vent cover motor, upper limit exceeded |
| B174B4A | Left air vent cover motor, Incorrect component installed |
| B174B4B | Left air vent cover motor, excessive temperature |
| B174C04 | Servo motor for right door window vertical vent – defective |
| B174C07 | Center air vent cover motor, mechanical malfunction |
| B174C1C | Center air vent cover motor, Voltage implausible |
| B174C22 | Center air vent cover motor, upper limit exceeded |
| B174C4A | Center air vent cover motor, Incorrect component installed |
| B174C4B | Center air vent cover motor, excessive temperature |
| B174D04 | Servo motor for right door window horizontal vent – defective |
| B174D07 | Right air vent cover motor, mechanical malfunction |
| B174D1C | Right air vent cover motor, Voltage implausible |
All 1472 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.