Hello everyone,
I'm driving Skoda Fabia mk2 and recently one problem occurred. When I switch A/C (climatrotnic) on cooling all functions work as it should, but when shut off radiator fan continues to blow, same thing happens when fan kicks in for to cool the engine. Present code is 00706 and on klimatronic it spills out 2c2 code. Important thing to say is that when I disconnect climatronic controls, fan stops and everything seems ok, fan turns on/off normally when cooling the engine. I have been suggested that climatronic module is faulty but not diagnosed for sure. Has anyone have any experience with something like this?

It is not unusual for vehicles to have the fan run on for a few minutes after switching off the engine. This helps to cool the car and prevent engine damage.If as you say, everything works fine, perhaps you are seeing a fault when there isn't one!

I'm afraid you misunderstood me. After activation, trough AC or engine cooling, fan isn't switching off at all, until the engine is turned off. Or, to clarify it more clearly, fan will kick in even on first start after night - engine stone cold. But when I disconnect AC module nothing of these symptoms occurs.

Inspect the connector of the refrigerant pressure sensor in the high pressure line near the engine coolant expansion tank (look for corrosion).

Or look at VCDS data for refrigerant pressure in measuring blocks of HVAC module. See what numbers it shows.

You can probably look at measuring blocks in there which say if the HVAC module is demanding fan function (at stage 1 (slow) or stage 2 (full speed)).

 

It is OK/normal for the fan to run when A/C is switched on even if the engine coolant is completely cold; refrigerant pressure >9 bar will trigger stage 1, and >16bar stage 2, even with no heat in the engine coolant. But if you switch off A/C the fan should go off, as it should if the pressure drops below 12 bar (stage 2 down to stage 1) or 6.3 bar (stage 1 off).

Those observations are based on a climatic rather than climatronic system, but I don't know why there would be any difference.

Edited 31 October, 20214 yr by Wino

Ok, recently I get a hold of obd11 diagnostic tool, not yet familiar with all of the functions, but in some live data measurement it shows 3bar refrigerant pressure, with AC on its steadily climbing and with off numbers go down but fun spining at full speed all the time. This is definitely out of my comprehensive range and will take car to another electronic specialist. If it comes to breakthrough I'll post any news 👍

Update. While waiting for electronic specialist to be available, I came across on used climatronic module for dirt cheap money. I had to take opportunity, bought it, fitted it and everything seems to work just fine. All problems, mentioned above, has disappeared. I'll try to find someone who could repair original module from the car, just to have one as spare part. 

Useful information, for those who maybe could have same/similar problem, is that on European market you could find spare one, used for 50€, used with some kind of 2yr warranty for 260€ and new for around 620€ 😬

Great news. I suspect a FET transistor has failed short-circuit.

If I manage to repair it, I'll make new post about what was the problem and how much it cost.

The connections relevant to fan activation are pins 8 and 9 of the 16-pin connector at the Climatronic unit, so follow circuitry towards what's pulling each of those to ground/0V to trigger the relays in the fan control module.

I expect you will find one of those pins is shorted to 0V all the time.

Ok Wino, you provide very useful informations and I want to thank you for that. 

Now, if you have some free time, can you explain why did Skoda or better VW (or maybe its not just theirs design alone) made that fan function to be intertwined between A/C and engine cooling. Isn't it better for those two to be separate systems?

The same fan cools the radiator, the intercooler and the aircon condensor, the fan control relay will be triggered by the Climatronic and engine control modules.

 

There is not the physical space to have the radiators seperated with seperate cooling fans.

^ Good explanation, thanks for saving me thinking about it.

Tiny correction being that the radiator (dual) thermoswitch is the other input (on this car) that feeds into the fan control module , not the engine ECU; I think.

Edited 2 November, 20214 yr by Wino

5 minutes ago, J.R. said:

The same fan cools the radiator, the intercooler and the aircon condensor, the fan control relay will be triggered by the Climatronic and engine control modules.

 

There is not the physical space to have the radiators seperated with seperate cooling fans.

Ok, this is clear to me, but as I understand how things work in case of my car control for engine cooling goes through AC module. Isn't it better for those two systems to be separated.. 🤔

They are separated. 

Either refrigerant pressure reported to HVAC module triggers fan control module or engine coolant temperature as sensed by the radiator thermoswitch triggers fan control module.

 

But if either input is faulty, like the HVAC one in your case, the fan will be forced to operate.

Because they are sensing the need for cooling of two different heat exchangers, it wouldn't be wise to design it so that both inputs must agree.

So, I think that we elaborated this subject enough to be of some use in future study of Fabia cooling and chilling cases 😎