Audi A4 Wiring Diagram: MSA 15.5 Controller

Translated on 22-10-2026, 21:55.

Hi everyone, does anyone happen to have a wiring diagram for an Audi A4 from the years 1996-1997?

I have a control unit, model 8.97, but it has an 80-pin connector, which I can't use because I have a 68-pin connector.

I would be grateful for any answers.

Hat Audi die gleiche Pin Belegung wie VW. zB. Passat.

It's about converting a 1-liter or AFN engine to a Caddy 14d. The engine control unit (ECU) will be from an Audi A4 automatic transmission.

Do you need to change any settings on the control unit via the diagnostic connector to switch from automatic to manual transmission?

The clutch pedal signal, pin 68/17, needs to be retrofitted to the wiring harness.

Translated on 22-10-2026, 21:56.

Hi,
You should recode the MSA15 to switch mode (-> diagnosis) if that is possible.
(If you provide the part number, I might be able to tell you.)
The wiring for the clutch and the second brake pedal input is different in Audi vehicles compared to Volkswagen vehicles. This is either due to a difference in the vehicle's wiring harness.
Modify it accordingly or use a different control unit.

Best regards,
Micha

Translated on 22-10-2026, 21:58.

Thank you for the response.
Bosch part number 0 281 001 425/426.

Audi, number 028 906 021 CE.

Control unit manufactured in May 1996.

Yes, I believe you can switch it using the diagnostic connection, but I read about it in the T3 bus forum, but I can't find the text anymore.

I've also heard that the clutch and brake signals are different.
However, I doubt that's the case, which is why I'm looking for the circuit diagram.

Someone told me that the pinout was the same until the newer 80-pin model was replaced.

44 (receives 12V from the brake system) is the brake light, and 20 (is interrupted when braking) is the brake light control signal (4-pin brake light switch).

17. When coupling, it is interrupted by a normally closed switch (ventilation valve).

Just like with my Golf 3, I need it in writing; I've already invested a lot of money in this control unit. The immobilizer has been deactivated, and the engine has been tuned to 140 horsepower.

Translated on 22-10-2026, 22:00.

turboandy wrote:

...I have already invested a lot of money in this control unit. Immobilizer deactivated and tuning to 140 horsepower

.
If the person who made it can't tell you how the pins are arranged, then...
How to convert an automatic transmission to a manual transmission (yes, it's possible with the 021CE), you should seriously consider...
Think about what you're actually investing in...

Best regards,
Micha

Translated on 22-10-2026, 22:02.

I now have the wiring diagrams for the 1.Z and AFN engines, manufactured between 1995 and 1996.

Sure, here is the translation of the text from German to English, in PDF format:

[PDF]

**Translation:**

In PDF format.

I've also managed to get another automatic transmission with the AFN I bought.

Got the number 028 906 021 CK.

Can this also be switched via diagnostics?

The wiring harness is perfect. Unfortunately, the cable for pin 17 of the clutch pedal switch is missing.