T4 ACV: Find Consumption Signal Pin (1997)

Hi everyone,

I'm basically new here because I had forgotten about my old account.

Anyway, good day to you.

Now, to the question.

I have been searching for the pin associated with the consumer signal on the engine control unit for about a week now.
because I installed a Multifunction Display (MFA) in my T4 2.5L TDI.
So far, everything is working fine, except for the power consumption display.
VW is unable to provide me with a suitable wiring diagram for this.
That means the wiring is documented up to a certain point (ZE), and then it suddenly stops.
I only know that it goes from Tacho 28/26 (pin 26) to U1/1 on the control unit (ZE), and then connects back out to G2/1. After that, you disconnect it.
Then I called Bosch (the manufacturer of the control unit) so that they could provide me with the pin number.
The answer was that this control unit was manufactured in Salzgitter, and I should inquire there.
And there, as one might expect, I am unable to reach anyone from the list of designated contacts.
VW is currently making things very easy for themselves by saying that there is NO estate (wagon) with an MFA (Multi-Function Display) available for my year of manufacture for a TDI engine.
Okay, but what exactly did I install then? A speedometer up to 220 (km/h), and it's even accurate. A tachometer up to 5000 (rpm). The fuel gauge is similar to a T4, but without showing the number of liters.

Okay, so which is the pin for the consumption signal on the engine control unit?
It's a module with 68 pins. Pin 9 is not connected and might be usable, but I don't have an oscilloscope to measure it.
Or does anyone have this information for me?

Thank you in advance.

Leigh.

Is there anyone here who can comment on this?

Is there anyone here who works at Bosch and could inquire about this matter at the Bosch facility in Salzgitter?
They refused to give us any information because we were outsiders.

Hello.

Could it be that you emailed me about this some time ago?

I found something once, but then I forgot about it.

According to the wiring diagram, pins 28 and 37 on the control unit are connected, but it is not specified where these connections lead to.

Pin 9 is also not assigned in the circuit diagram.

That could be you, if you are the '[email protected]'.

You haven't sent me an answer yet.

Bosch is probably too lazy to do anything about it.
That's sad.
VW is struggling to navigate its own internal affairs and isn't saying anything about it.

I guess I'll have to use the oscilloscope to find it.

I'll check pins 28 and 37.

But also pin 9.

What exactly should the output signal be?
I once read something about a rectangular waveform with a peak voltage of approximately 1 volt.
Could that be possible?

I would be grateful for any advice.

Best regards, Leigh.

Okay, so pin 28 connects to the climate control system and carries the signal that the control unit receives.
'If this is enabled, it will adjust accordingly.'

I don't know what pin 37 is at the moment!
I need to check that out!

Pin 37 also connects to the climate control system as well.

Now I'm just as clueless as before.

This issue has now been clarified.

For the engine control unit T4, 75 kW (ACV), manufactured in 1997.

is PIN 9 responsible for the consumption signal .


Okay, anyone who needs information about retrofitting a Multifunction Display (MFA) to a T4 speedometer up to the year 1999 can check here.

http://www.t4forum.de/wbboard/thread.php?threadid=3859&boardid=8

Sincerely,
Hightower