Audi AFB STG: Repair & Replacement

Hello everyone,
Can someone tell me where the engine control unit (ECU) is located and what its pinout is?
Here's the translation:

'It's about an Audi A6 V6 AFB, model year 1998.'

greetings

Richard.

And which control unit are we talking about?

Hello Rainer,

Is it about the engine control unit (ECU) that should, among other things, control the VTG solenoid valve? Is that the engine ECU?

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

'Hello'

Richard.

Hello Richard,

Do you really need the entire pinout, or would a specific excerpt suffice? Are you experiencing any particular problem?

Hi,

I need the PIN number for the LDR valve.
My problem is that the VTG rod isn't coming out completely.
After checking all the vacuum hoses I know of and even replacing the solenoid valve itself, I now want to check the control signal to the solenoid valve.
Interestingly, the sound is hollow when the engine is cold, but after a few times of pressing the accelerator, it's not quite as hollow anymore.
In a cold state, the valve's operating frequency is 80%, while in a warm state, it is 45%.
Of course, in neutral.
Maybe you can help me, or someone who has experienced something similar.

Best regards.

I'm sorry, I can't translate that word because it doesn't seem to be a real word. Could you please provide a different word or phrase?

Hello Richard,

Did you adhere to the specified conditions during the measurements? If not, you should disregard all the measurement results.
The duty cycle at full load should be between 45% and 95%.
What data do measurement block 4 and 11 display under full load?

Hi Michael,
You're quite the early bird.
Okay, measurement block 4.
/min ° ° %
2065 4 4.8 64.3
2181 4.4 4.8 62.3
2297 4.6 5 56.8
2436 4.8 5.2 55.6
2575 5.2 5.4 54.4
2691 5.6 6.2 53.7
2830 6 6.4 52.9
2946 6.4 6.8 52.5
3086 6.8 7.2 51.3
3225 7.2 7.6 50.9
3341 7.6 7.8 48.5
3457 8 8.2 48.1
3573 8.4 8.8 46.9
3689 8.8 9.2 45.8
3805 9.2 9.8 45.8
measurement block 11
/min mbar mbar %
1717 1928 1642 72.6
1833 1958 1795 60.4
1972 1979 1969 48.9
2088 1989 2162 41
2227 1999 2346 25.3
2366 2009 2009 38.3
2482 2020 1693 48.5
2598 2030 1652 50.9
2714 2040 1714 48.1
2854 2040 1795 48.1
2970 2050 1856 47.7
3086 2071 1918 50.5
3225 2081 1979 49.7
3341 2101 2030 51.3
3457 2122 2081 54.4
Everything at 3000 RPM.

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

'Hello'

Richard.

Hello Richard,

It actually looks quite good. Are you experiencing any performance issues?

Hi,
Okay.

It's a bit underpowered, especially on the highway. It doesn't feel very responsive, even though it does eventually reach its top speed.
In measurement block 11, he has a kink at the charging pressure.
2227 1999 2346 25.3 <I think he's under too much pressure here, but also...
2366 2009 2009 38.3 is too tightly restricted, resulting in a value of 1693.
2482 2020 1693 48.5, needs to be reduced by the amount indicated by the print.
After that, he has to start the pressure build-up process all over again.
Besides that, the air mass is too small, approximately 600. However, the mass flow rate (LMM) is okay.

Best regards.

Richard.

Hello Richard,

Please share any other measurement data you have. Have you read the articles about VTG?

Hello Michael,

'I have it all here, everything is standard. The unit is in good condition, as I mentioned, the solenoid valve is new.'
Hoses sealed.
What other measurable values are of interest?
Can I get a short-term greeting message?
Richard.

Hello Richard,

That would be interesting as well.

Measurement block 3, idle state.
Measurement block 8 and 10, under full load.

Hello Michael,
block3 idle.
/min mg/R mg/R %
742 223.7 341.5 95.5
742 223.7 341.5 95.5
742 227.7 341.5 95.5
742 227.7 341.5 95.5
742 231.6 341.5 95.5
742 235.5 341.5 95.5
742 231.6 341.5 95.5
742 227.7 341.5 95.5
742 223.7 337.6 95.5
742 223.7 341.5 95.5
742 219.8 337.6 95.5
742 223.7 341.5 95.5
742 227.7 341.5 95.5
742 231.6 341.5 95.5
742 223.7 341.5 95.5
block8 is full.
/min mg/R mg/R mg/R
1902: 45.8, 37.6, 24.2
1995: 50.5, 37.6, 31.1
2134 49.3 38 34.5
2250 48.3 38.3 33.6
2390 47.7 38.3 34.5
2529 47.1 38.3 35.8
2668 46.4 38.6 37
2807 45.8 38.9 37.3
2946 45.5 39.2 37.6
3086 45.2 39.5 37
3202 44.9 39.8 35.8
3318 44.5 40.5 35.5
3434 44.2 40.8 35.8
3550 43.9 40.5 36.1
block10 is full.
439.6 959 1397 22.4
490.6 959 1499 100
537.7 959 1652 100
604.5 959 1846 100
655.5 959 2040 100
714.4 959 2234 100
541.6 959 1999 100
529.9 959 1714 100
549.5 959 1714 100
561.3 959 1775 100
573.1 959 1846 100
580.9 959 1918 100
580.9 959 1969 100
580.9 959 2009 100
596.6 959 2071 100
604.5 959 2122 100

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

'Hello'

Richard.

Hello Richard,

to Block 3:
The target and actual values for the air mass should be within +/- 20 mg/H. In your case, it's approximately 120 mg/H. Has the engine been idling for about 10 minutes before the measurement? This difference suggests an insufficient EGR rate.

Regarding Block 8:
In field 4, the value represents the fuel injection quantity limit based on the detected air mass. This value should be greater than 41 mg/H. Possible causes could include a faulty mass airflow sensor (MAF) or excessive exhaust gas recirculation (EGR) under load.

Regarding Block 10:
Even before the turbocharger kicks in, the air mass is significantly below 750 with almost maximum boost pressure. Even if the boost pressure were to reach 2300, it is unlikely that a value exceeding 750 would be displayed.

Hello Michael,

Thank you for your effort.

I checked immediately, and the connector for the AGR valve wasn't properly connected.
(would explain a lot).
I will run the tests again.

See you later.

Richard.

Hello Michael,
Here I am again with some new measurement data.
measurement point 3, idle.
/min mg/R mg/R %
766 247.3 247.3 38.3
766 247.3 247.3 38.3
766 251.2 243.4 39.5
766 247.3 247.3 39.1
766 247.3 243.4 39.5
766 247.3 243.4 38.7
766 251.2 243.4 39.8
766 239.4 247.3 37.5
766 247.3 247.3 38.7
766 255.1 243.4 39.8
mb.4voll
/min ° ° %
1786 4 4.4 61.2
1926 4 4.6 64.3
2042 4 4 60.8
2181 4.4 4.4 59.2
2320 4.6 4.4 56.4
2482 5 5 52.9
2622 5.4 5.8 52.5
2761 5.8 6.4 50.5
2877 6.2 6.6 51.7
2993 6.6 6.8 50.9
3109 6.8 7.4 49.3
3248 7.2 7.4 48.9
mb.8voll
/min mg/R mg/R mg/R
1462 56.8 38.9 23.8
1740 52.7 38 28.5
1856 51.5 38 33.3
1972: 50.5, 37.6, 36.1
2134 49.3 38 38.9
2274 48.3 38.3 41.4
2413 47.4 38.3 42.7
2552 46.7 38.3 35.8
2714 46.1 38.6 34.8
2830 45.8 38.9 35.1
2970 45.5 39.2 35.5
3086 45.2 39.5 35.8
3225 44.5 40.2 36.1
3341 44.2 40.5 36.1
mb10voll
mg/R mbar mbar %
372.9 989 1020 100
384.7 989 1102 100
404.3 989 1183 100
427.8 989 1275 100
467.1 989 1387 100
526 989 1540 100
600.5 989 1744 100
675.1 989 1979 100
734 989 2213 100
741.8 989 2346 100
573.1 989 1867 100
565.2 989 1775 100
569.1 989 1795 100
573.1 989 1856 100
584.8 989 1928 100
592.7 989 1979 100
mb11voll
/min mbar mbar %
1369 1877 1265 93.1
1717 1928 1581 80.1
1810 1948 1744 62.7
1949 1979 1928 50.9
2065 1989 2101 45.8
2204 1999 2213 37.5
2343 2009 1989 46.6
2482 2020 1703 55.6
2598 2030 1703 53.7
2714 2040 1775 54.8
2854 2040 1877 54.4
2970 2050 1948 52.1
3109 2071 1999 54.8
3248 2091 2050 56
3364 2101 2101 56.4

It's a lot, but it's better than having too little.

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

'Hello'

Richard.