T4 2,5 Tdi , ACV Baujahr 2001 mal wieder Leistungsverlust! | Posts 48+

"I'm wondering if there are any differences in the static readings between the ambient air pressure and the actual boost pressure when using the old versus the new MAP sensor, and how the pressure diaphragm on the wastegate behaves."
Does the adjusting rod move in or out of the container when pressure is applied?

Ahhh okay.
The test has been performed, and the sensor value is higher than that of the previous one. The pressure switch is working correctly and doing what it's supposed to do.

However, what's much better is that I finally found the bug!
Please provide the latest log file.

I read in another forum that the connector for the turbocharger control unit and the connector for the EGR valve are the same, differing only by a small extension cable!

Since I worked on the valves one by one during the replacement process, there's no way I could have mixed them up! Also, because the bus was running perfectly fine after I bought it, the problem couldn't have existed before.

So, it seems the only possibility left is that at one of the two workshops that had access to the vehicle, either the cables were incorrectly installed or, even worse, deliberately tampered with in an attempt to win back a customer. (I'm not going to dwell on that right now because I'm really angry about it...)

After swapping the cables and taking it for a test drive, the car felt completely different. It's working as it should again, and the turbo boost is back to normal.

Best regards, and I'm happy.
Thomas.

I'm not entirely convinced yet.
Which of the logs in the file are you referring to? The one from today at 3:45 PM? Then probably yes.
For safety's sake, I would disconnect the connector from either the N75 valve or the EGR valve (with the engine running) and check for any error messages.
hg
Herbert.

@Jeeper-Thomas
Didn't I take a Screenshot of the distributor injection pump?

Am I missing something?

Well...
Select value block 0.
Then you can select the TDI timing.

Select ACV MSG 15.
(the VPE goes into its "default state").

But first, make sure it's properly warmed up (fuel temperature approximately 140) .

I would also check the possibility of swapping the connectors using a process of elimination.
It's possible, given that the valves are very close together.

Great, if it actually works .

How do the readings from the altitude sensor and the pressure sensor compare when the system is stationary?

@Ruedi: Which measurement blocks are responsible for this?

The bus is still running great, and even on uphill sections where it previously went into limp mode, it hasn't stalled (limp mode). I will test the other things again in the next few days. I have to go back to work today, so there isn't much time left during the day...

Best regards,
Thomas.

If those two connectors were reversed, the interruption in the EGR cable harness would also have been registered as an error. I'm speaking from experience as an ACV owner.
Where was this information? At the very least, after Rainer pointed out a potential EGR valve issue in the very first response, someone could have looked into it.

I have listed the identified errors here. However, the one you described has never occurred. This is likely because there was no interruption beforehand. And the AGR valve works in a similar way.

Best regards,
Thomas.

As I mentioned, I had already experienced this problem after a Volkswagen workshop removed and reinstalled the engine.
"AGR short circuit to ground."
But it's good that it's now working as it should.

If the valves are electrically identical, swapping the connectors will not affect the output stages in the MSG (Main System Generator) at all.
The turbocharger pressure control and the exhaust gas recirculation (EGR) system are working together in a fascinating way. The EGR system controls the operation of the turbocharger's wastegate valve: when EGR is desired, the turbocharger pressure is increased (if possible), and when high turbocharger pressure is needed, the EGR valve is opened.
hg
Herbert.

Herbert wrote:

If the valves are electrically identical, the output stages in the MSG will not notice anything if the connectors are swapped. The turbocharger pressure control and the exhaust gas recirculation (EGR) system are working together in a fascinating way. The EGR system controls the operation of the turbocharger's wastegate valve: when EGR is desired, the boost pressure is increased (if possible), and when high boost pressure is needed, the EGR valve is opened. hg Herbert

.

Hi there, that's correct! No error entries.

I just tried it out on my car.
Logs are identical, and the loading process is lagging behind.