Golf TDI Ride Height Adjuster Upgrade (1Z)

Hallo, ich stehe vor dem Problem, in einem Golf TDI Bj 1995 den Höhenkorrekturschalter (oder Höhengeber, Umgebungsdruckmesser etc.) nachrüsten zu müssen. Wararound?
"It should have been integrated into the engine control unit (ECU). It was, but I had to replace the original ECU due to problems with the immobilizer. According to the workshop, because I don't have the login code (which was supposedly on the spare key, but the plastic strip is no longer available), it's not possible to pair a different ECU with an internal sensor to my keys. So, an ECU 028906021C from a 1994 model was installed. Unfortunately, this one has an external height sensor. My wiring harness probably isn't designed for that (or where would I find the three-pin connector?). What I need is a pinout diagram for the connector on the engine control unit (for the 021C version or 1994 model) so I can match the pins to the wiring diagrams (I have the pin numbers, but I don't know where those numbers are located on the connector)."
Unfortunately, the STGs are completely different internally; the newer ones only have one circuit board, while the 021C has two circuit boards stacked on top of each other. This makes a simple resoldering impossible .

Then, just out of curiosity, I have another question:
What causes the preheating system indicator light to come on after starting the engine in low temperatures (T < -5 degrees Celsius), and then to stay on for about 4-5 minutes, even though the preheating process is actually completed after about 30 seconds (which I verified with an LED connected to the preheating fuse)? So, the indicator light remains on. If it goes off after 4-5 minutes, this effect doesn't repeat when the engine is warm, but only when the engine is really cold. At temperatures above -5 degrees Celsius (estimated, unfortunately no precise values), this effect doesn't occur. However, even in those conditions, the preheating process is still happening, as indicated by my LED, which shows a preheating time of 5-20 seconds depending on the temperature. The indicator light only briefly illuminates (about 0.5 seconds) and then goes off.
Could this be related to the exchange of the control units? Otherwise, the engine behaves normally. But I definitely want to know what it's doing .
According to the workshop, no related error codes are stored in the control unit. Only one error code is present, specifically F96, due to the missing height sensor.

Thank you very much!
Stefan.

Hi,

I'm too lazy to check right now, but please verify if both are 16-bit microcontrollers (with aluminum casings).

Oh no - just saw:

Quote:

Unfortunately, the STGs are completely different internally; the newer ones only have one circuit board, while the 021C has two circuit boards stacked on top of each other. This makes a simple resoldering impossible.

You are mixing up an MSA15 (16-bit with WFS) and an MSA12 (8-bit without WFS).

The pin configuration doesn't match either.

It's best if you get an MSA15 STG from the same engine and re-solder the WFS of your old STG. Your trusted chip tuner will know more .

Everything else will end up as a chaotic and haphazard endeavor with an uncertain outcome.

Hello.

I would appreciate it if you could still take a look.

Perhaps a few words about myself. Even though I don't have "expert" status here, I've been working on my own Golfs for 20 years now. I'm also comfortable with electronics and soldering, etc.

The old control unit had to be removed because it was having problems with the WFS (the WFS control unit was resoldered and tested, but it wasn't the issue). I don't see resoldering as a very promising solution in this case. Furthermore, a tuner probably won't help much either.

The engine control unit (ECU) from the 1994 model (also TDI, 1Z) has two B58368 units (Siemens). These are likely controllers based on the Intel 386, a 32-bit CPU. Where are the 8 bits "measured"? Like the newer unit, it also has two EEPROMs and two other memory modules, which unfortunately cannot be identified due to the lack of a type code. Furthermore, I have traced all the pins in the wiring diagrams for the 1994 and 1995 models, and they are identical and pin-compatible, except for the connections for F96.

Apart from all the theorizing: I'm currently doing a practical test, and the car has been running with the 94 octane fuel system for the past 6 months without any problems or issues. In that sense, I consider the outcome of this "tinkering" - if switching a fuel system can be considered as such - to be very positive .

I wouldn't classify the issue with the preheating light as a defect, at least until proven otherwise, because it depends on the ambient temperature. Furthermore, I can't be sure that the original control unit didn't do the same thing. I only became more aware of it this winter as the battery started to weaken (which has now been replaced, and wasn't the cause).
I just need to connect three cables to clear the error message related to the faulty height sensor during the TÜV inspection (since the AU test has been replaced by this process). The control unit seems to be using a fixed value in this case, at least the tester showed a value of around 1000 mbar. If I knew the pin numbering on the control unit, I would even solder in a voltage divider if necessary.

I also have an engine control unit (ECU) from the same engine, but as mentioned, I no longer have the login code, and unfortunately, the old chips from the waste heat system are no longer usable. And before I start doing complicated things to fix that, connecting the height sensor seemed like the easier option.

So, I'm asking again, please take a look.

Thank you.
Stefan.

Quote:

Furthermore, I have actually traced all the pins in the wiring diagrams for the 94 and 95 models, and they are identical except for the connections for F96, which are pin-compatible. ... I would also solder in a voltage divider if I only knew which numbering the pins have on the control unit.

Huh? You're writing a lot of nonsense up there. For time reasons and because of the search function, I won't go into it any further.

Just use a voltage divider instead of the altitude sensor, and that should be it. For the turbocharger and supercharger, the ambient pressure doesn't matter as long as you're not driving on extremely high mountain roads.

Best regards, Rainer.

Pfusch und Fünfg'rad wrote:

...The engine control unit (ECU) from the 1994 model (also TDI, 1Z) has two B58368 units (Siemens). These are likely controllers based on the Intel 386, a 32-bit CPU.

There's definitely no 32-bit computer in there.
These are two derivatives of the 8031 (8-bit controller), likely the 80517 (if I recall correctly).

Best regards,
Micha

Let's keep it simple:

Does anyone happen to have the pinout diagram for the connector or socket on the engine control unit (ECU) for a Golf 3, year: 1994, engine code: 1Z (with an external height sensor for the ECU)?

Thank you very much.
Stefan.

Pin33: Ground/Mass.
Pin 40 signal output.
Pin 41 +5V

Hi,

Thank you. These are the connections as shown in the wiring diagram I have.
Only where can I find the connector (in the wiring diagram T68), pins 33 / 40 / 41? Which pins are those?
That is the information that I am missing.

Hello,
Stefan.

Please .

The outer contacts on the connector are numbered, while the others can simply be counted.

Hello,

@ Wiesel: Finally, someone who understands me . Thank you!!!

"@slow-moe: Nooooo, I only have the ECUs (an extra 94 model for tinkering) here, and I was desperately searching for a numbering on the connector (sorry, not a plug - I wrote that wrong). Of course, I didn't think about the connector in the car (since there's another 94 ECU installed there)."

@Rainer: I used the search terms "pinout" or "connector layout," but I didn't find anything under "pin layout."

Thank you for your patience!
Problem solved, time to get out the soldering iron.

Stefan.

Hi, just wanted to give a quick update. It took a while, as the rust needed to be dealt with. Everything worked out, and I can still drive my "heating oil Ferrari" around for another 2 years. In the meantime, I managed to find an engine control unit with the same license plate letters as the original and had it programmed. Somehow, I got the impression that it needed more fuel with the "C" setting than before. Let's see what the preheating indicator light does next winter.

Thanks again for your help!!

Hello,
Stefan.