April 2020-manufactured Octavia Scout 2.0TDI (MkIII facelift).

Is there an indicator in the infotainment system, or which can be read with an OBDEleven, to check the AC cooland level/ system function?

I was driving in the crazy southern European heat a few days ago and there were times when it felt like the system wasn't cooling quite as well as it usually would/ used to.

The engine temperature was always fixed at 90° (after the initial very few minutes heating up); engine RPMs were in the usual 1800-2200 range (gear S7, driving at between 100km/hr - 120km/hr), no extraordinary hill-climbing.

The moments when it felt that the system wasn't cooling as well as I'd like, I tried lowering the cabin set temperature, which didn't seem to improve the air coming from the vents. The amount of airflow seemed consistent with the fan speed dial setting. And it didn't seem to relate to the current heat load (e.g. it sometimes happened when I happened to be in shadow or going through a long tunnel, not always in an open part of the road in full sun).

thanks,

There is no dash indication for AC refrigerant level, you have to use a diagnostic tool to check the pressures before and after the compressor with the AC on.

Thank you, @PetrolDave .

On 13/07/2026 at 11:09, PetrolDave said:

There is no dash indication for AC refrigerant level, you have to use a diagnostic tool to check the pressures before and after the compressor with the AC on.

Coming back to this, when I initially read @PetrolDave 's response, I (mis?)understood "a diagnostic tool" to mean something specific to the high-pressure gas system, but, did you mean an OBD-II reader e.g. the OBDeleven that I own?

I asked Google the question of whether modern cars actively monitor A/C system gas charge/pressure, etc, and came up with:

https://autoacrepair1.com/how-can-i-check-my-cars-air-conditioning-systems-freon-level-without-opening-the-hood/

.. which comments:

"You cannot accurately confirm your car’s exact refrigerant charge without accessing the A/C system with proper service equipment. An OBD-II scanner may show A/C pressure-sensor data, compressor commands, clutch status, evaporator temperature, and diagnostic trouble codes, but these readings only provide diagnostic clues. They do not directly measure how much refrigerant is inside the system."

I'm aware that the OBDII information includes 08 - Air Conditioning, but what I haven't found is how complete is the monitoring done by the Octavia III (Facelift), in the sense of "Occasionally spending the time to have an OBDII device read the A/C control unit is actually likely to help you notice an impending A/C problem before you notice that the system isn't cooling properly"?

Any thoughts?

thanks,

You can read AC system pressure with OBD eleven, I did it last week to confirm I have a partially depleted system.

Doing this will only be a first look at the system especially while it is running under load, you should be able to check for typical running (high side) pressure for the fridge gas in your system, online - ambient temperature dependent.

Thank you, @rum4mo and @CianKT ; I'll take the car out some time in the next days to where I can park it, running, warmed up (easy in the Mediterranean heat!!), with the A/C running for a while, and plug in my OBDelevent.

rum4mo, I apologize, I don't quite understand - what does the "online - ambient temperature dependent" mean?

cheers,

-Jay

8 hours ago, rum4mo said:

Doing this will only be a first look at the system especially while it is running under load, you should be able to check for typical running (high side) pressure for the fridge gas in your system, online - ambient temperature dependent.

I probably meant using Google etc to answer the question "what is normal high side pressure in a car AC system?" - or similar, the cruel thing is, someone probably on briskoda.net has quoted expected high side and low side running pressures - but I've forgotten where I read that. You need to know which fridge gas is used in your, ie R-134A or the later fridge gas R-1234yf , a label under the bonnet will tell you which gas is used.

Edit:- for example what is the high side and low side running pressures for a car ac system - Google Search

Edited 31 minutes ago31 min by rum4mo