Climate compressor T5 only runs occasionally, shutdown condition 12

Here's the translation:

'This is a T5 Multivan, see the photo with the equipment codes.'

Der Klimakompressor schaltet sich im Fahrbetrieb ca. alle 5min zu und läuft dann für ca. 1-2min. Dann schaltet er sich wieder ab, Abschaltbedingung ist 12 (also 'abgeschaltet durch Motorsteuergerät via CAN') Im Fehlerspeicher wird in der Climatronic und im Motorsteuergerät kein Fehler abgelegt. Wenn der Klimakompressor läuft, ist die Ausströmtemperatur bei ca. 10 Grad, kühlt also sehr gut. Druck der Anlage bei Zündung an beträgt 5-6 bar, im Betrieb ca. 13bar. Würde Is there an error message displayed when there is too little refrigerant?

Ich habe von einer Rückrufaktion bezüglich des Kühlerlüftersteuergeräts gelesen. Es würde bei manchen T5 vorkommen, dass dieses nach dem Abstellen des Fahrzeugs durch Ansteuern der Lüfter die Batterie komplett leersaugt. Genau dieses Phänomen hatte ich vor einer Woche, die Batterie am Fahrzeug war nach kurzer Standzeit von 3 Tagen komplett entleert. Per Stellglieddiagnose lassen sich beide Kühlerlüfter ansteuern. Was What exactly is being done in this recall campaign?

'Furthermore, I've noticed some unusual entries in the engine control unit, as you can see in the photos. I suspect that someone may have tried to program it before, but didn't know what they were doing.'

I am grateful for any help.

Hi.

Have you ever, at the moment of shutdown, read out everything possible from the engine control unit (ECU) that might indicate a problem?

For example, torque requirements or thermal limits?

The idea behind it is that the engine "isn't feeling well" and therefore wants to get rid of comfort features that put a strain on it, such as the air conditioning system.

I think that if I press the accelerator pedal all the way down, the air conditioning will also turn off.

Or, it might be installed in a similarly unusual way in the T5, like in Audis, where certain sensors (like the climate pressure sensor) are not connected to the climate control module (CCM) but to other modules. In the A4/6, the pressure sensor is located in the Body Control Module (BCM). If the sensor is faulty, the climate control displays "deactivation due to message," but the faulty sensor is explicitly indicated in the BCM.

m;

Hello, thank you for the reply. I didn't notice anything unusual in the engine control unit. Revving the engine above 3000 RPM while stationary results in fault code 18.

Here are the details for the climate control unit. These printouts were retrieved using my Autel 'workshop tester' via 'control unit information.' Why does every control unit display 'intake manifold pressure ---- intake side leak/...'?

Quote:

18 = Magnetic coupling (N25) deactivated (motor speed above 3000 RPM AND speed = 0 km/h)

Quote:

12 = Magnetic coupling (N25) deactivated by the engine control unit via CAN

.
As far as I can tell...

Please check the temperature readings on the engine for plausibility (refer to sections MWB 7 and 68 onwards, specifically exhaust gas temperatures).

Was the climate control system recently serviced? The pressure increase you described, which causes the system to shut down when accelerating, could indicate an excess of refrigerant in the system. Alternatively, the cooling fan might not be working, preventing the condenser from dissipating heat, which could lead to a significant pressure and temperature increase.

Unfortunately, not all the temperatures in my diagnostic tool are accurately labeled. There are no temperature readings for MWB 68 and following, and I suspect that only vehicles with a DPF (Diesel Particulate Filter) have a corresponding exhaust temperature sensor. I haven't been able to find a temperature reading that falls within that exhaust temperature range. The T5 does not have a DPF. I have attached the reading for MWB 7.

'The air conditioning system hasn't been serviced. With the engine running, the pressure in the AC system is 4 bar at 20°C. When it actually starts working (which is only when the car is moving, as it doesn't even turn on when stationary), the pressure is around 13 bar. So, it's unlikely that there's too much refrigerant, right?'

Both radiator fans can be activated via actuator diagnosis. However, it is now clearly audible that neither fan is running. Does the second fan always have to run when the air conditioning is active (i.e., the compressor is running)?

Hey, are those weird screenshots actually from the VAG tester?

Fehlercode 00386 ergibt in einem Motorsteuergerät Null Sinn und im Klimasteuergerät steht 00785.

00785 indicates: temperature sensor - control panel - G56, which would make sense.

Your quirky tool (which one?) is babbling something about the intake manifold pressure in the air conditioning system (doesn't that exist there!)

dieselschrauber wrote:

Your ... tool (which one, please?) ...

master_328 wrote:

... Car lift "workshop tester" ...

Bye.
peace

Quote:

Autel "Workshop Tester"

Ok, das habe ich übersehen. Irgendwie sind die Fehlereinträge (?) aber für den Lokus. DeThe first one would be...

Quote:

00386 - Minusausgang Audiokanal für Sprache/Telefon.

and has no place in a motorcycle's engine control unit.

Perhaps it's time to use a working diagnostic tool?

Hello, thank you for the feedback. I have an AUTEL Maxidas 708, not a VAG tester.

The screenshots are not from reading the error memory; they are simply 'control unit information.' The nonsense like 'intake manifold pressure ---- leak on the intake side/...' can be ignored there. I don't know where that information comes from, but it's the same for all VAG vehicles.

The error memory of both the climate control unit and the engine control unit are empty.

The diagnostic tool itself actually works.

The key factors are the shutdown condition 12 and the empty error memory. Now the question is, what can cause shutdown condition 12 from the engine control unit's perspective? Is there a list or something similar for this?

I just drove the car again. On the highway, at speeds above 100 km/h, the air conditioning was working constantly. As soon as the speed is reduced, the compressor turns off, and it doesn't even turn on below 80 km/h...

The speed signal seems to be fine and is present in various control units. I suspect the radiator fans. These are forced to turn by the airflow. Is it possible to read the actual speed of the fans? If so, where? When exactly should the second fan be running? Does it always run when the air conditioning is turned on, or is it controlled temperature-dependently? As mentioned before, both fans can be activated via actuator diagnostics.

You cannot read the fan speed directly, but it displays the fan's power level, typically ranging from 10% to 100%. The fans are usually controlled by the MSTG (Main System Terminal Group). Also, check the refrigerant pressure. It should be between 10-15 bar on the high-pressure side, depending on the outside temperature. At temperatures between 25-35 degrees, it can also reach 15-25 bar. If it exceeds this value, the system will shut down.
Je höher der Hochdruck ist, umso stärker werden die Kühlerlüfter angesteuert, sollte mam locker im Motorraum hören und fühlen sowie sehen können.
The fans run constantly when the air conditioning is on.

How does the on-board voltage behave?
If the climate control system is running at speeds above 100 km/h (gear or RPM?).
How does it behave in a lower gear at a comparable engine speed?

Best regards,
Micha

How does the on-board voltage behave?
If the climate control system is running at speeds above 100 km/h (gear or RPM?).
How does it behave in a lower gear at a comparable engine speed?

Best regards, Micha

The onboard voltage is fine, and the engine speed apparently has no effect on the compressor engaging. Driving at 'high speeds' does not make the system start up.

How would a faulty radiator fan control unit manifest itself? When I activate the fans via actuator diagnostics, they only run at one speed (I assume 100%). Is this normal, or should the actuator diagnostics allow the fan speed to increase in stages, in 10% increments from 10% to 100%?