T4 AJT ESP Issues: Troubleshooting & Solutions

"Hi, I have a VW T4 Caravelle from 2002 with the AJT 2.5 TDI engine. My problem is that the car was heavily smoking black during driving and then stalled. Since then, it hasn't started properly. I've been able to pinpoint the source of the problem to the mass airflow sensor. Here's my issue: I can see the target value in function block 02 and observe how it changes when I adjust things. In function block 019, which shows the initial values, I should have 1 volt and 5 volts, but instead, I only get 1 volt on both readings. VCDS reported an error code: "mass airflow sensor - lower limit."
Can someone help me with this?

[Translating...]

Autoscan?

I'll send it over later.

It's not showing me any errors right now.

Okay, all the measurements are within acceptable limits except between values of 3 and 5, or 6 and 7, where there is no resistance detected.

Okay, yes, that's right. And before I forget, the anchor switch – specifically, the quantity selector – isn't working at all; it doesn't engage or disengage when you turn the ignition on.

"Someone is objecting to the automatic scanning."
Does "no resistance" mean a measured value of R = infinity or R = 0?
"hg"

In my case, "no resistance" means an infinitely high resistance.
I'm sorry, I could have described that better.

Okay.

Okay, and why doesn't the slider perform a reference run when starting? And how are the values "1,... V" obtained in the VB 19?

You're reading at least 1 MΩ up there, right?

Okay, that seems right, but under the measurement block "019," there's a "start" and I think a "stop" function, or something like that. The voltages have always been around 0.7V and a good 4V, but now both are showing the same value, which is about 1V.

Okay, here's the translation:

"Now, please provide the car scan."

Suspected cable break in the area of the starter motor.

Hi.
Okay, so the explanation for why the FB 019 values were at 1V: There are two hidden fuses inside the unit, above the relays. One of them was blown. Since then, it's been working fine.