Coolant fan control/Need diagnostic assistance

I don't believe it, the endless tinkering with my ARL/Leon (built in 2005) is becoming too much.
Really annoying!

This time, the problem is with the fan control. In the FS, the fan control shows a short circuit or open circuit to ground (18080).
Sporadically, it seems to be, but it's probably not because the error can't be fixed!! or rather, it reappears immediately.

'However, it's important to note that the Klimabetrieb stufe 1/2 system is functioning perfectly.'
At a temperature of 96 degrees, (with the air conditioning off), the fan switches to level 1.
The engine is not getting hot. This doesn't bother me at all!


Okay, that's it. So far, I have conducted:
-Component diagnosis (without fan control when using a radiator fan controller)
-Fan control unit replaced
-Pins on the fan and MSG checked for oxidation - no issues found.

Unfortunately, I don't have the correct schematic, so I'm having trouble determining the pinout.
to find out.

Are you aware of such an error? What could be the cause?
What diagnosis would you perform?

Hi,
Leon 1m arl, yes?
Are all the fuses on the battery okay? It can also break down.
Check the fans by unplugging the connectors on the bottom right.
There are 3 contacts each. Just give the fans a little power with the jumper cables, and switch the connections around. Each fan needs to have both a fast and a slow setting.
The slow setting stage often malfunctions. Fan price at 160€

I will check this first.

Speculation:
Have you ever compared the MSG encoding with that of a vehicle without this error code?
Possibly, the MSG still thinks it can control the fans (relays) itself and is unaware of the fan control system (STG).
/End of speculation

Jub 1M ARL,

I checked the fuses; they were okay, but I replaced them all anyway.
It seems like both fan speeds are working, as the Klimat control is only set to level 1 for both.
When the cooling requirement is higher, it switches to level 2, so everything is okay!

A recoding has not been performed by my side.
Only one defective clutch switch was replaced two weeks ago. But I don't see a direct connection to the current defect.

Interestingly, the error also persists even when the fans are set to a specific speed.
Even after completely disconnecting the fan {FAN}, the error could not be cleared.
Normal because of a cable interruption?

Level 2 will be activated when the coolant temperature reaches a certain threshold. This often happens now in the summer when the air conditioner is turned on. This is because the hot air from the air conditioner's condenser passes through the engine's cooling system.

Would say yes, right

The question is why does the engine control unit (ECU) detect fault 1, 'motor fan control,' even though all stages are, more or less, controlled by the temperature sensor or the climate control system?
So, I don't need the engine control unit to save the engine from overheating.

When is the secondary control from the PLC used?
How is this controlled with PWM?

I have checked the two fans according to your instructions. Are they working in both stages?
on both fans.

What should I do according to your opinion?
Maybe try a different fan STG again?

After about 4 hours of troubleshooting, I found the problem.
Cause: A cable break in the main cable harness, approximately 30cm after the engine control unit.

From the outside, the error was not visible, nor were there any signs of wear and tear.
After removing the cable tie, oxidation was visible on the cable for the fan control.
Cable replaced. Everything is okay.

Thank you for your assistance.

Thank you for the feedback!

Can you please provide a more detailed description of the cable break?
I might be experiencing the same problem.

THANKS!