ECU replacement for AGR/AHF

Hello everyone!

If the control units of the AGR (Abgasrückführung) and AHF (Abgasheizung) are not compatible, can an AHF control unit theoretically be connected to an AGR wiring harness, or are there major issues involved?

Apart from the N75 having a different electrical resistance, there shouldn't be any other electrical differences, or am I mistaken?

It is specifically about a...
AHF-MSG 038 906 018 GN
as a replacement for a...
AGR-MSG 038 906 018 A

Could that work?

I would like to experiment a bit, because I believe that even the boost pressure control could work with the wastegate turbocharger. The pulse width modulation (PWM) values output by the engine control unit (ECU) for boost pressure control seem to be in the right direction (low PWM value = wastegate closed or aggressive turbocharger control for high boost pressure, high PWM value = wastegate open or gentle turbocharger control for low boost pressure). It remains to be seen how well the regulation will actually work, but in my opinion, it's worth a try, as long as it's technically feasible from a wiring perspective.

I hope that the MSG (Message Sending Gateway) only monitors the N75 driver stage for a broken connection and does not check the resistance value. Then it might work.

Let's hear what you think about the feasibility of this project! Is there a risk that I will damage the engine control unit (ECU) or other control units (combination instrument, ABS, etc.) or the sensors if I connect this incompatible ECU to my wiring harness?

Regards,
Alex.

Hm, I need to find and check the wiring diagrams.

You need to connect the WFS (likely referring to a specific system or component) to the new MSG (likely referring to a specific system or component) if it's compatible, and then your engine should start running.

@Julian:

Quote:

Hm, I need to get some wiring diagrams and take a look.

And who here in the forum has wiring diagrams available?
Does anyone have diagrams or schematics for the AGR (automatic air recirculation) and AHF (automatic headlight) systems in an Audi A3, perhaps in electronic format?

Or is someone able to answer the question based on their experience?

I would like to add that my AGR has a Pierburg mass airflow sensor. However, I have no idea whether the AHF, specifically the one mentioned above, "I'm wondering if the engine control unit (ECU) is compatible with this mass airflow sensor (MAF), or if a Bosch MAF and a different wiring harness are absolutely required for the sensor to function correctly."

Thank you for your knowledgeable assistance.

Regards,
Alex.