Webasto problem

[nilsson]

I have a Peugeot 407 SW HDI 2007.
The problem is that the webasto do not start.
Fault code with Webasto diagnostic is defective control unit 1001.

When i read the temperature with the diagnostic program i indicate 74 degree C, but the coolant is much cooler.
I test to get som snow äround the heatercamber on the webasto, near the temperature sensors, than the indicated temperatur increase. I than put som heat of it, and the indicated temperature decrease.
It seems like the resistance in the glow plug is correct, and it also started to get hot if i just put some voltage to it.

So when i start the diagnostics and start the burner, only the exhauste fan starts, and program indicate the speed of the fan. The software tells that next step is glow plug, but it never starts.

Did someone seen these problem before, and can give me some advice?

Thanks and best regards.

[autodestak]

the system has a high temperature sensor that may be over-reading and will not let the system start. the diagnosis does not give errors?

[Alex Gomel]

temperature sensor or control unit defect