Altitude Sensor Error 00528: Troubleshooting Guide

I'm getting the following error: (00528 - Altitude sensor) in a test control unit.
According to VW, this part was installed in vehicles in Austria and Switzerland.
The STG number is 028 906 021 B.
Is the problem caused by the lack of a height sensor in the car, or is it a faulty component within the control unit (ECU)? What exactly does the height sensor regulate?

Hi,

What is a "test control unit," is it a development prototype?
The "altitude sensor" measures the current air pressure, and these values are used to adjust the turbocharger boost pressure and protect the turbocharger when driving at high altitudes.

Click through the measurement blocks in the engine control unit; in measurement block 10, field 2, you should see the air pressure displayed. What value do you see there, and what vehicle are you dealing with, including the engine code?

Best regards, Rainer.

The diesel engines for OE (Österreich) and CH (Switzerland) already had altitude-dependent maximum power limits in the Golf 2.
This will limit the engine's power when you are at a high altitude in the mountains.

There, the air is so thin that the turbochargers would likely fail completely in order to achieve the desired (absolute) boost pressure, because the difference between the outside air pressure and the boost pressure is much greater.

German MSTGs (e.g., my 028 906 021 AF) also also have an external pressure sensor, but I don't know if it's referred to as a "height sensor."

m;

AFAIK, Road drives a Passat with a 1Z engine.

Yes, it's a Passat with the 1Z model code.

@Rainer: Regarding the test device, I still don't know (even after 9 months) why all the tuning chips I've installed so far have a soot limit that doesn't exceed 40mg, which prevents the programmed power output from being achieved. That's why I'm going to try it with a different engine control unit and have a chip installed in it.

@Dieselmartin

Where is the external pressure sensor located on the 1Z model? The external pressure is displayed in group 10. However, VW told me that it's a fixed value. So, do I have a sensor for this, or not?

Here's another thought: If only the STG units in the East and Southwest had altimeters, then it would be clear that the STG is displaying the error because I don't have one myself.

I only know about the "__only in OE and CH" from the mechanical swirl chamber Golf 2 models (which had variable full-load injection timings).

My 1Z also lost power in Italy at an altitude of 1600 meters - unfortunately, I didn't have time to log the data.

A fixed size? So, I think the value changes for me - I wanted to use it to make weather forecasts .

The sensor is located inside the MSTG itself, and it should have a round, slotted opening so that air pressure can enter .

m;

Sure.

I only logged the 010 value once, but it did "move," even if only slightly.

m;

I find that interesting... In all the logs I've made with my AT control unit, which is the original one, the barometric pressure was ALWAYS at 1020.
Sometimes, when idling, it would occasionally display a reading of 1009, but mostly it showed 1020.
Could it be related to the fact that the smoke limit in group 8 doesn't exceed 40 - perhaps because the control unit is receiving incorrect data?
I had suspected it already, but VW told me that it's a constant value - and I guess I have to believe that somehow... - or you can correct me if I'm wrong.

See here:

As discussed in previous threads:

40 mg is already more than a typical 1Z injection and should produce around 102 horsepower.

Somewhere there must be a field that always displays 51 mg, which is the maximum value the pump can deliver. Maybe it's showing a lower value there.

The "Barometric Pressure" readings in this log were 989, 992, and 997 mbar.

I can gladly record some more data on my way home; I'll gain about 100 meters of elevation, which should be visible in the pressure readings.

m;

I know that 40mg is already more than the standard dosage.

However, in the log file, I'm currently more concerned about the consistently reported barometric pressure of 1020 millibars.

"Can anyone definitively tell me whether these values are constants in my engine control unit (ECU)? Also, does anyone know if there's a component within my ECU that should be measuring this, and how would I check it? As I mentioned, the part number is 028 609 021 AT."

Certainly, the number is not 028 609 021 AT.

but 028 906 021 AT.

Small lathe.

dieselmartin wrote:

I would be happy to log my data again on the way home; I'll gain about 100 meters of elevation, which should be visible in the data.

But if so, then probably only with a difference of one level.

The printing resolution is at least 12 mbar for the LD model.

And for every 8 meters of altitude gained, the ambient pressure decreases by 1 mbar (in lower altitudes, the rate of decrease becomes even greater).
Therefore, 100 meters of altitude theoretically result in a maximum pressure difference of 12.5 mbar -> and if things go wrong, the logarithm value might not even exceed a threshold.

Thank you again for starting to include air pressure readings in the logs.

But could someone perhaps tell me how I can find out if VW is telling me something that's not true? Does my car have a sensor? How can I check it, replace it, or who can help me with this?

As I said: VW only provides complete control units, and they apparently have no idea what components are inside, and I'm not familiar with those components either.

Roadrunner505 wrote:

But could someone perhaps tell me how I can find out if VW is telling me nonsense, whether I have a sensor in my STG, how to check it, replace it, or who can actually help me with this?

1. Unscrew it and take a look inside.
On the AFN-MSG, it was a small, black plastic component, about the size of a thumbnail, that stood upright on the circuit board.

2. Loosen the MSG (Message Sending Unit), record the pressure readings, and somehow try to apply slight positive or negative pressure to the ventilation port (in the AFN, the housing was practically airtight except for the ventilation).
If you manage to change the internal pressure in that way, you should also be able to see corresponding changes in the log.

I still have a spare 028 906 021 HD (MSA 15 from ALE) at home.

I can try to find a suitable pose for that and help you search for the sensor.

My 021 AF has a round knob with air vents.

m;

hello,

Check this out...

/viewtopic.php?t=1659&highlight=


so, not with a fixed value. unless you wait for 15 seconds, then the device probably takes a fixed value, like in my case.

Best regards.