Skoda Yeti Diesel Auxiliary Heater Problem

From your description, a defective glow plug seems plausible. Has the ventilation system been checked recently? A faulty temperature sensor might also contribute to the heater's malfunction. Have you observed any coolant leak? Insufficient coolant can impact the heating system's performance. How is the heat control responding when the engine is at operating temperature?

Are there specific diagnostic steps I should perform to confirm the glow plug issue before replacement?

Considering the error memory and the symptoms, it is likely the glow plug. However, without specialized tools, definitively confirming its failure can be challenging. Do you possess the necessary equipment for electrical testing? A visit to a qualified workshop would be prudent for a conclusive diagnosis and repair.

The glow plug was indeed the problem. The repair set me back 440€.