Seat Alhambra diesel cold start issue

The symptoms you describe, such as poor engine running during cold starts, the stored error, and increased fuel consumption, strongly suggest a defective PTC heater. To confirm, a diagnostic check should be performed to read the specific error code. This will help determine if the electric auxiliary heater is indeed the source of the problem. I would check the voltage supply.

Thanks for the quick response. Can you elaborate on what I should check regarding the voltage supply? What is the expected voltage?

A defective electric auxiliary heater is the most probable cause. Without knowing the specific error code, further remote diagnostics are limited. Testing the voltage supply requires specialized tools and knowledge to prevent electrical damage. You could check the fuses related to the heating system as a first step. If the fuses are intact, I advise taking the vehicle to a qualified workshop for professional diagnosis and heater repair of the HVAC system.

I took it to the workshop and you were spot on. It was indeed the electric auxiliary heater. The heater repair cost me 350€. Thanks a lot for your help!