Faulty Control Unit: Diagnosis & Repair

Hello!
I recently had the error memory of my Passat 3B TDI, engine code AFN, manufactured in 1997, checked by an acquaintance. One error was found: "Control unit defective, 65535 037!" The error could be cleared, but as soon as the car warmed up, the error reappeared. Can anyone tell me what "037" means or what exactly might be broken?

Sure, here's the translation:

"Thank you in advance."
Tom.

Hi,

Is the control unit in its original condition?

Best regards, Rainer.

Yes, I think so. I bought the car from a 55-year-old man.

If the car is otherwise driving normally, I would ignore the error.

Best regards, Rainer.

Unfortunately, he doesn't do that. When the engine is warm and the error occurs, it loses power from around 2000 RPM.

Which diagnostic system did you use to read the error code?

If using VAG-COM, please send me the version number, address, and license code via private message.

Best regards, Rainer.

65535 - Internal Control Module Memory Error 37-10 - Faulty - Intermittent.

I know where that's coming from. In my case, it's still the external pressure sensor that's providing incorrect values (due to a lack of time to fix it).

*g
jones

No, not VCDS (Vag-Com), a friend had it diagnosed by the dealer using code 1551.
The external printer - is it possible to buy one separately somewhere?
Best regards,
Tom.

How about you check first to see if HE is even the cause of the problem before you ask such questions?

Rainer K. wrote:

How about you first check to see if HE is actually the cause of the problem before you ask such questions?

Okay, since the error disappears after restarting and only reappears when it's warm, things should be fine when it's cold. So, let's log some measurements and see what might be causing the problem.
For me, it's the external pressure sensor – but that doesn't necessarily mean it's the same for you. The error code only indicates that something is wrong with the control unit.

*g
Jones.

Hello everyone in the forum, I'm new here. I own a Passat from 1997 with an AFN engine, 81/110 horsepower, and 150,000 km on the odometer, all original.
I'm very happy with the car, but I have the same problem as tomk0711:

"Error: Control unit defective, error code 65535 037. This error could not be cleared until I completely disconnected the control unit. However, it reappeared the next day. I can clear the error every day, but after a few kilometers, it comes back."
My friend, who works at Volkswagen, used an original VW diagnostic tool to read the data.

I want to have the engine control unit checked and possibly repaired tomorrow; it will cost 250 euros.
It takes 5-6 days.

Do you already know what the cause is?

Best regards, maremio.