Auxiliary heater Audi, Seat, Volkswagen, unlock, error code 02251 (Solution)

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

Channel 42 also applies for unlocking the Sharan 7N1.