After errors occur during the start-up or operation of the auxiliary heater (parking heater), it needs to be unlocked or reset. To unlock the auxiliary heater (parking heater), follow these steps:
- Access the control unit of the auxiliary heater using VCDS, address 18.
- Then, select "Adaptation/Adjustment" and, in channel XX, save the value 1 to unlock it.
For Audi A3 (8P) / Seat Altea/Toledo (5P) / Seat Leon (1P) / VW Eos (1F) / VW Caddy (2K) / VW Golf/Golf Plus (1K/5M) / VW Passat (3C) / VW Touran (1T), XX = 42.
For the Volkswagen T5, XX = 3. For the T6, in the "Adaptation" dropdown menu, select "Water pump lock".
Possible reasons for error code 02251 - Heater unit locked:
- Defective auxiliary heater/supplemental heater
- Low fuel level or insufficient fuel supply