Hi everyone,

I'm facing a strange issue with my parking heater (Skoda Superb III). The Webasto only works as an auxiliary heater (automatic engine warm-up while running). It refuses to start independently via the console button, remote fob, or the app.

When I try to activate it manually, only the cabin blower turns on and displays the target temperature, but the heater itself doesn't fire up.

Here is what I've checked so far:

• Fault Codes: There are no error codes in Module 18 (Auxiliary Heater).

• Operating Conditions: All parameters for a cold start (ambient temp, fuel level, battery voltage) seem to be met.

• Circulation Pump (V55): It appears to be functional. I've confirmed that it remains active for about 160 seconds after the engine is turned off before shutting down.

• Status: The device is not in "locked" mode.

One specific parameter caught my eye and I'm not sure if it's relevant: "Engine operating status = Not recognized".

I am stuck and have no idea what else to check. Has anyone encountered a similar issue where the heater works perfectly with the engine on, but fails to trigger in parking mode?

Thanks in advance for any help!

Yesterday I catched my neighbour, who happens to be a Webasto/Eberspacher sale and repair centre, has a Tiguan with aux heater, and services my SIII who has one as well, and we discussed your case.

It is puzzling, because upon three unsuccessful starts, the aux heater unit "locks" to prevent damage, and only diagnostics can unlock it.

If you have tried to start it more times, as I believe you had, and it did not fire, but at the same time you got no errors and it did not "lock", then probably there is a mis-communication between car and heater, the latter not recognizing has a fault.

You said you run diagnostics (what?) on Module 18 Aux Heater, could you be able to run also on the Engine ECU and on the Gateway - think it was Module 19?

This would highlight a possible comms issue.

The heater needs to know engine status to know when to ramp-up, idle or maintain its firing/heating cycles, so if it says 'not recognized' this is another indication there is a signal missing somewhere.

Lastly, you say when you start "manually" by pushing the button, the blower comes on but the heater does not start. What does the indication light do? Stays on, flashes, or turns off like after a second or two?

And what about the indicator in the remote?

More info to keep digging on this interesting case...

Is there enough fuel? Or tank almost empty?