SMAX Parking Heater Issue

That's not ideal! I've got an SMAX too, though I'm unsure of the year. I had a similar problem last winter. There was no heat at all, and it turned out to be something with the climate control system. Was yours completely dead, or just not getting very warm? Did you check the coolant level?

Good shout on the coolant, I'll double check that first thing. But yeah, it's completely dead. There's no sign of life from the auxiliary heater whatsoever. Was your issue exactly the same, completely dead, or just weak heat? What fixed it in the end?

Okay, mine was also completely dead, like a switch was flipped. I messed around trying to find a coolant leak but honestly, you're better off taking it to a workshop. It's probably the glow plug, like you suspect. That was the diagnosis on mine, and the error codes sound familiar.

Right, that confirms my suspicions then. Looks like a trip to the shop is in order. Thanks a bunch for sharing your experience; it saved me a load of pointless fiddling. The garage confirmed it was indeed the glow plug and cost me 440€. At least now I know what to expect next time!