T4 AHY ECU: Intermittent Faults & Repair

Hello everyone,
I have a T4 with an AHY engine (115 kW, 5 cylinders) that suddenly lost power about a week ago, and the following error code appeared in the diagnostic system:

Steuergerät-Teilenummer: 074 906 021 M
Bauteil und/oder Version: 2,5l R5 EDC 00SG 1716
Codierung: 00002
Werkstattcode: WSC 02743
1 Fehler gefunden:
65535 - Steuergerät defekt
37-10 - defekt - Sporadisch

You can clear the error, and then it will have 'full' performance again.
However, it eventually reappears during the journey, and you can notice the loss of power.

What can you do besides taking the diagnostic device with you and clearing the error every few kilometers?

Best regards,
KFH

This is likely the 'old' one with an internal map sensor. Is this an original part, or has anyone already worked on it before?

Yes, a hose goes into the control unit. It's probably the MAP sensor.

It's original, the car is completely stock. Everything is original, no modifications or chip tuning, etc.

I checked the hose. It's clear and not oily. Only the clamp at the intake manifold connection was quite loose - I tightened it a bit.

So far, the error hasn't occurred again (it was deleted on Tuesday). However, the car hasn't been driven much. And it hasn't been driven on the highway yet.

That means the problem likely still exists.

Best regards,
KFH

New control unit has been ordered...

I'm experiencing the same problem with my TDI.
Did replacing the control unit make any difference?

Well, let's just say 'partially.'

The error message is gone, of course. But it still doesn't seem to be performing at its full potential.
Tomorrow, the diesel filter will be replaced, and then we'll see how things go.

Thank you for the response.
I forgot to mention that this issue occurs in a Golf 3 with the engine code ALE (so not in the vehicle listed in my signature). I suspect the ambient pressure sensor, as the power loss is barely noticeable. I'll take some measurements and post my results later.

Best regards,

Does your control unit also indicate 'intermittent defect'?
Or are you just experiencing a loss of power?

Have you already checked the hose to make sure it's not blocked?
You could also try unscrewing the control unit and checking if the sensor is possibly contaminated with oil or dirt.