Vacuum Regulator Issues: New Control Unit, Same Problem

edit Mod: For better clarity, here is the background information: https://community.dieselschrauber.org/en/viewtopic.php?t=19228


I installed a new control unit last week. Everything was working perfectly and running smoothly – until now!

I was driving on the train, at a relatively fast speed, and suddenly, after I switched from one track to another, the car went into emergency mode. I was actually accelerating quite gently at the time.

Upon arriving home, two errors were found in the log.

00519 Sensor for intake manifold pressure - G71, short circuit to positive.
00575 Intake manifold pressure, control differential.

How did that happen again?

"Over the past six months, I've replaced almost everything except the turbo."
- LMM
- Pressure transducer
- VTG made operational.
- Turbocharger boost hoses partially replaced.
- Engine control unit replaced.

What could be the cause? Could this happen if the boost pressure hoses have too small or too large a diameter? In the workshop, one of the hoses was replaced, and I'm not sure if it had the correct diameter.

I'm really at a loss now. At least the error message about a faulty control unit didn't reappear...

Probably the charger...

marcel.d wrote:

... 00519 Sensor for intake manifold pressure - G71, short circuit to positive. ...

Is it a brand new gearbox or a "used" one?

That's because it's an error message that suggests a missing ground connection on the G71.

"It's a good used one. But if the problem is with the control unit (STG), it would be the second one that has the error. With the first one, it started the same way, and eventually I had a persistent "STG defective" error, and above 170 km/h, the limp-home mode would activate due to a "charge air pressure control difference" error."

To what extent do the hose diameters have an influence?

I'm not really keen on investing in a new charger right now...

Yesterday, he gave me that same mistake again.

00519 Sensor for intake manifold pressure - G71, short circuit to positive.

However, without intake manifold pressure differential regulation! Of course, the emergency mode also came on...

marcel.d wrote:

Yesterday, he gave me that error again: 00519 Sensor for intake manifold pressure - G71, short circuit to positive. However, without intake manifold pressure differential regulation! Of course, the emergency mode also occurred...

The error also occurs if the boost pressure is consistently *much* too high, or if the tuning data is manipulated.

"I will be re-enabling the LDA (Lane Departure Assist) over the next few days and will monitor it continuously. The error has occurred twice so far, but never under full load. The first time was when merging from one highway onto another, where I was able to accelerate normally in 5th gear. The second time was yesterday during normal driving at approximately 130 km/h, with the accelerator pedal lightly pressed, which was completely unexpected, as I had only experienced it before under full load."

It's been a few years now, but I once encountered a similar error while working with AJM.

It was due to a valve that generates the vacuum for the VTG adjustment.
It was just dirty. However, using brake cleaner to verschandeln it wasn't really the right approach; it made it stiff. I applied some dry lubricant, and then everything worked smoothly again.
Possibly investigate the cause of the pollution.

However, as I mentioned, I'm not entirely sure if it was exactly the same error message.

Regards,
Nick.

@marcel.d

Why are you starting a new topic?

I searched again.

My mistake was something else entirely.

Error code: 17965.
Turbocharger pressure regulation: Limit exceeded.

Possible causes:
Hoses connected incorrectly, not properly attached, leaking.
Sorry.

Regards,
Nick.