Auxiliary Heater Conversion to Stand Heater

hello,

The following problem has been reported in a Touran model year 2004:

During the conversion from a supplementary heater to a parking heater, the control unit of the supplementary heater was replaced with the one from a parking heater; unfortunately, this caused some problems.
The auxiliary heater is not working due to two error codes stored in the system.
not available with the "old" auxiliary heater.
02754 - Heating element for fuel preheating (Z66)
010 - Interruption/Short circuit after positive voltage - Intermittent.
Sure, because the "old" auxiliary heater was not available.

01237 - Fuel shut-off valve (N109)
010 - Interruption/Short circuit after positive terminal.
"Does anyone know where this valve is supposed to be?"

edit: more detailed description of the problem:
The auxiliary heater starts briefly when activated via the remote control, but then the start-up process is interrupted after the fan runs for a short time.

Sorry for the double attachment.

You're welcome, austrogolfer.

hello,

I have now examined the problem mentioned above in more detail, and in doing so, I discovered different (hardware) versions of the Telematik-Unit (TTU) used in the Touran.
In (seemingly) newer TT models, a fuel shut-off valve is installed *within* the auxiliary heater, which was not present in (seemingly) older versions.
Unfortunately, this shut-off valve is not mentioned in either my VW or Webasto documentation; but oh well, it works now.

However, I would still be interested in learning about the reason for installing this shut-off valve.
If anyone has information about this, please let me know briefly.

Thank you, Austrogolf.

Under certain circumstances, fuel could potentially be forced further into the combustion chamber of the auxiliary heater (e.g., blocked fuel vent, full tank, and high temperatures). That's why the valve was included in the new versions.

Does a dosing pump for the auxiliary heater actually still allow fuel to pass through when it is without power or voltage?

I haven't tested that with my Webasto Thermoflop C yet. I'm not sure why I would, because it works perfectly well as it is.

Quote:

I have now looked more closely at the problem mentioned above; in doing so, I had to identify different (hardware) versions of the TT control units installed in the Touran. In (apparently) newer TT models, a fuel shut-off valve is installed *inside* the auxiliary heater, which was not included in the (apparently) older versions. Unfortunately, this shut-off valve is not visible in either my VW or Webasto documentation; but what can you do, it works now.

What was done so that it now works? Was the entire heating unit replaced ?

hello.

Yes, the entire device was replaced. Originally, I only wanted to replace the heat exchanger to avoid having to open the water circuit.
While replacing the submachine gun, I noticed the two additional cables on one of the connectors, but I paid little to no attention to them (unfortunately).

Best regards, Austrogolf.