Webasto STH Diagnosis: Troubleshooting Guide

Hi!

Has anyone had a positive experience connecting their diagnostic adapter to an aftermarket Webasto STH (standing heater)?
When I connect my adapter (the schematic is not from this site, but it works with optocouplers) and start the corresponding diagnostic program, the data from the STH is immediately read and displayed. However, after that, nothing else can be done. It's not possible to erase the memory, send commands, or do anything else. The error message that always appears is "Timeout...".
I'd like to know if this might work better with your adapters, or if you have any suggestions for me?

Thank you.
pretzel

small addition:

Problem solved. The cause was that I was working with a DOS window under XP. It seems the heating system didn't like that... It works perfectly fine under "DOS only" mode!!!

See you later.
pretzel

How did you manage to integrate the Webasto into the VW diagnostic system? Also, what kind of car and heater (aftermarket) do you have?

Hello Varianti!

You misunderstood me. I did NOT include the STH diagnosis in the VW diagnosis. The diagnoses are completely separate, and I use different programs for each. It's an aftermarket Webasto unit.

Best regards,
pretzelman01

(The circuit diagram is not from this page, but it uses optocouplers.)

Hi Brezelmann,

Since many people (including myself) are likely interested in a corresponding circuit and programs for diagnosing Webasto auxiliary heaters, it would be great if you could post a link to the relevant page.

Thank you in advance and best regards.
-Private

PrivatBereich wrote:

Here, there are certainly many (including myself) who are interested in a corresponding circuit and programs for Webasto auxiliary heating system diagnostics

.
Yes, I am also part of that group.

I am also immediately part of the group of interested people.

So, how did you do it, and with what?

Possibly also via private message.

Hello!
Okay, now I'm going to express my opinion on this:
Okay, I had the schematic diagram for my diagnostic interface saved under the following location back then:

http://www.planetfall.com/~jeff/obdii/

"I found it. I sent Rainer this link, and he took a look at it (I don't really know much about electronics...). Anyway, it seems that this adapter is similar to Ulf's simple adapter. Therefore, Ulf's adapter should also work. Why don't you try it out?"
Was das Programm betrifft, da müßt ihr mal Eure freundliche Bosch-Werkstatt fragen (...oder den Esel). Auf der Webasto DataTop CD ist dieses winzig kleine Dos-Programm zu finden, aber solange Rainer keine "Freigabe" von Webasto hat, kann er dieses natürlich nicht online stellen. VeUnderstandable, right?!

Best regards,
pretzel

Hi,
What is the exact name of the program? As you know, donkeys are not exactly known for being intelligent...

Okay, I'm ready. Please provide the German text you want me to translate.

That's also the case with Eberspächer...

If you want to have access to diagnostic codes, you need to purchase the large weekly timer.
It can read the codes. Otherwise, only the diagnostic tool is needed.

CU Gremlin.

Okay, so I now have a cable with an OBDII connector on one end. How do I connect this thing to which connector on the STH? Could someone possibly take a picture or explain it in more detail?

Okay, so the ODB connector obviously needs +12V and ground, which you can definitely find in the STH wiring harness.

In addition, the auxiliary heater has a cable that, according to the auxiliary heater installation manual, was described as 'for diagnostics, do not connect' (or similar). I believe the cable was yellow. It should be the only cable of the auxiliary heater (besides possibly the cable for summer mode switching, which I believe is brown and purple) that is not connected.

Since this cable is the only diagnostic cable provided by STH (and therefore doesn't have an L-line), it probably needs to be connected to the K-line of the OBD adapter.

However, I've only come to these conclusions through logical reasoning, and I don't have any practical experience to support them. I hope it's still correct.

Regards,
Private.

PrivatBereich wrote:

However, I've only come to these conclusions through logical reasoning, and I don't have any practical experience to support them. I hope it's still correct.

That is absolutely correct.

*Thread bump*

Can the diagnostic lead of the Thermo Top C (pin 1 of the 6-pin connector) be connected to the K-line (of my VW Passat 3B) to create a diagnostic bus in the car?

No, that's not possible.