Adapter Problems: Another Case

Hi,

I have a good understanding of physics, but I am not entirely familiar with electrical engineering .
The adapter for the ULF was built for me by an electrical engineer, and after I found and fixed 7 errors, my motto, as always, is: "Do everything yourself" -> so please don't give up immediately.

... I know, I know... remote diagnosis is usually difficult, but it seems my adapter is also having a problem with T3.

During the adapter test, LED 3 does not light up. Both circles of "OK 3" have been tested individually and are functioning correctly. When I bridge pins C and E on connector T3, LED 3 lights up. The L- and K-lines are providing 12 volts (relative to +). There is 0.6 volts between points B and C, and 10.4 volts between points E and B (the voltage source is supplying 12.8 volts, which indicates a battery, and the potentiometers are in the middle position).
I've read in the forum that this T3 (mine has "C557B PH0d" printed on it -> so a B-type?) can be replaced with a C-type or a Darlington 879?
During the VAG-COM test, only LED1 and LED2 light up alternately, and when attempting to access the control unit, the error message "no response from the control unit" appears.
I've been checking the circuit and components (resistors) all night, and I've also soldered in new, working ones, but without success.

I would be very grateful for a tip!!!!!!!

Best regards, Christian.

The transistors need to be NPN, yours is PNP. Please replace them.

ckone wrote:

The transistors must be NPN, yours is PNP. Please replace them

.

So, I found the error -> the transistors were wrong... and I paid the electrical engineer quite a bit of money for that... ...but thank you again!!!!! I'll report back when it works!!

Best regards, Christian.

ckone wrote:

The transistors must be NPN, yours is PNP. Please replace them

.

Hi.

Of course - just as an addition for people who may not have such in-depth knowledge of electronics:

PNP transistors instead of NPN transistors can render a circuit completely non-functional - it's roughly equivalent to connecting the car battery with reversed polarity and then expecting the TDI engine to run normally .

Hi,

One thing that would still interest me (and probably others) is:

Is it a good idea to install BC 547 C directly, or does the choice of transistor (A, B, C) depend on the voltage at the base?

Best regards, Christian.

haehnlein wrote:

Is it a good idea to install BC 547 C directly, or does the choice of transistor (A, B, C) depend on the voltage at the base?

Hi Christian,

Answer: Yes and no... (I'm not going to go into further explanations right now).

The A, B, or C designation indicates the current gain. In this application, a high current gain is desirable for T1 to T3, and the C designation offers the highest current gain.

This doesn't mean that the adapter with A-parts is generally non-functional - it depends on the characteristics of the other components, especially the optocoupler.

And I say yes. The transistors will be used in switching mode. The minimum gain must be somewhere around β=200. With the C-type configuration (β > 450), you are definitely on the safe side.
If there are 12 volts on line K, transistor T3 must conduct (collector voltage of T3 < 1 V). Otherwise, the transistor will not be turned on via R12/D7. To check this, you can connect a 10 kOhm resistor from the base of T3 to the positive voltage. In that case, T3 should turn on.
You can test the secondary circuit around LED3 by shorting pins 3 and 4 on OK3. Does the LED then turn on?
A common mistake is reversing the polarity of the transistors. To help prevent this, a 3D image has been incorporated into the circuit diagram.

Hi Andy,

My adapter only contains "Type B" connectors, and it's working great (now).
The Uc voltage from T3 is significantly below 1 volt.

However, C-types are fundamentally the safest and offer the highest level of functional guarantee in that regard, and I agree with you on that point.

At the same time, let me ask a different question: what actually drove a gasoline car driver like you (--> signature) to the diesel forum ?

Hello Ulf,

Even though I've only ever driven one diesel car in my life (a Golf I, 1.6L, 50 horsepower), I'm still a fan of diesel vehicles. However, my current annual mileage of less than 15,000 km, mostly consisting of short trips, doesn't make the economic use of a diesel feasible.
Many of the topics in the forum are also of interest to 'gasoline car' owners, as they describe general things related to vehicles (e.g., VAG-COM).
Furthermore, you'll get to know 'practitioners' and their 'practices,' which can also help you with general problems. There isn't a forum like www.benzinschrauber.de, though. That would be something for Rainer, right?

AndyO wrote:

My current annual mileage, which is less than 15,000 km and mostly consists of short trips, does not allow for the economical use of a diesel vehicle.

Hi Andi,

Based on typical calculations, a diesel car doesn't make financial sense for me, given that my annual mileage is less than 10,000 kilometers.

I bought my tractor when I was facing a daily commute of over 90 kilometers alone to and from work, but things turned out differently.

However, I'm not going to give it up, because it's just too much fun to drive.

The "typical" high maintenance costs associated with diesel engines are very limited in my experience: I've only been to a (competent independent) workshop once for a brake fluid change, because I didn't want to deal with the mess myself.
I've been doing the rest of the maintenance myself, following the maintenance schedule.

If you're a "disgruntled" diesel fan, try calculating it based on these premises.

Yippppiiiiiiiiiiiiieeeeeeeeeeee!

The adapter is working... I installed the BC 547 C transistors and it works!

THANKS AGAIN TO ULF AND RAINER FOR THE EFFORT AND TIME YOU PUT INTO THIS FORUM! AND OF COURSE, THANK YOU TO ALL THE OTHER COMPETENT FORUM MEMBERS AS WELL!!!!

....even someone like me, a complete novice in electronics, can get this thing running .

Best regards, Christian.

haehnlein wrote:

The adapter is running... I installed the BC 547 C transistors, and it works!!!!!!!!

Hi Christian,

if the communication works, it's good.

But just to be on the safe side, be prepared for the possibility that (with some kind of STG - Steuergerät, control unit) problems might arise at some point, and maybe order the parts for the upgrade to version 2.3 now.

ulf wrote:

But just to be on the safe side, be prepared for the possibility that (with some kind of STG, which is a type of engine control unit) problems might arise at some point, and maybe start gathering the parts for the upgrade to version 2.3 now.

No!

Hi Ulf,

"So, in my Passat and Seat Arosa, both gasoline models, the adapter was able to access all control units, including the airbag system!"

Best regards, Christian.

haehnlein wrote:

So, in my Passat and Seat Arosa gasoline cars, the adapter accessed all control units, including the airbag!

Hi Christian,

I'm happy for you .

And please share the data that you extract from your patient using VAGCOM regarding starting problems, etc.

Perhaps my airbag problem was also just a kind of revenge from fate for being so careless as a "developer" and not having measured the transmission characteristics before the release.
...forcing me to prioritize the trimmers for more important areas.

However, I still recommend that anyone experiencing problems with the 2.2 engine consider upgrading to the 2.3 engine.