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B3A1200 — Expansion valve for evaporator, low-temperature circuit (EXV2) – signal implausible

Expansion valve for evaporator, low-temperature circuit (EXV2) – signal implausible. 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 B3A1200

Porsche Taycan

Porsche 911 (992)

Porsche Panamera (971, 2017–2023)

Porsche Panamera (972, 2024–)

Porsche Cayenne (9YA)

How to read and clear B3A1200

  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 B3A1200 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 Thermal Management

B3A0800Refrigerant circuit shut-off valve (EAV5) – voltage too high
B3A0900Refrigerant circuit shut-off valve (EAV5) – temperature too high
B3A0A00Expansion valve for evaporator, low-temperature circuit (EXV2) – stuck open
B3A0C00Expansion valve for evaporator, low-temperature circuit (EXV2) – short circuit to ground
B3A0E00Expansion valve for evaporator, low-temperature circuit (EXV2) – temperature too high
B3A1100Expansion valve for evaporator, low-temperature circuit (EXV2) – fault
B3A1300Refrigerant circuit shut-off valve (EAV2) – fault
B3A1400Refrigerant circuit shut-off valve (EAV2) – temperature implausible
B3A1500Refrigerant circuit shut-off valve (EAV3) – fault
B3A1600Refrigerant circuit shut-off valve (EAV3) – temperature implausible
B3A1700Refrigerant distribution valve 3 – malfunction
B3A1800A/C Refrigerant Distribution Valve "C" Actuator Temperature, Range/Performance

All 636 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.