Home › Fault codes › P1BB900
P1BB900 — Radiator fan relay – permanently active
Radiator fan relay – permanently active. 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 P1BB900
How to read and clear P1BB900
- 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 P1BB900 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 Thermal Management
| P1BB000 | Left radiator fan (RF3) – voltage implausible |
| P1BB100 | Left radiator fan (RF3) – temperature implausible |
| P1BB200 | Left radiator fan (RF3) – current implausible |
| P1BB600 | Radiator fan relay – short circuit to ground |
| P1BB700 | Radiator fan relay – short circuit to B+ |
| P1BB800 | Radiator fan relay – open circuit |
| P1BED00 | Expansion valve for evaporator, low-temperature circuit (EXV2) – part number implausible |
| P1C0100 | Expansion valve for evaporator, passenger compartment (EXV3) - fault |
| P1C0200 | Expansion valve for evaporator, passenger compartment (EXV3) – mechanical fault |
| P1C0300 | Expansion valve for evaporator, passenger compartment (EXV3) – temperature too high |
| P1C0400 | Expansion valve for evaporator, passenger compartment (EXV3) – voltage too high |
| P1C0500 | Expansion valve for evaporator, passenger compartment (EXV3) – voltage too low |
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.