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U12A300 — Coolant expansion valve, A/C, No communication
Coolant expansion valve, A/C, No communication. 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 U12A300
How to read and clear U12A300
- 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 U12A300 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
| U129400 | Right rear upper body vent motor, No communication |
| U129500 | Right rear upper body vent motor, implausible message |
| U129600 | Left side window defroster door motor, No communication |
| U129700 | Left side window defroster door motor, implausible message |
| U129800 | Right side window defroster door motor, No communication |
| U129900 | Right side window defroster door motor, implausible message |
| U12A400 | Coolant expansion valve, A/C, implausible message |
| U12A500 | Outside air quality/air humidity sensor, No communication |
| U12A600 | Outside air quality/air humidity sensor, implausible message |
| U12B900 | Control unit for driver assistance systems – missing message |
| U12F100 | Rear A/C Control Head 1, no communication |
| U12F200 | Rear A/C Control Head 2, no communication |
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.