Air conditioning not working

[Scut]

Hi All,

Wondering if anyone has any advice please.

2017 T6 shuttle with climate control.

Owned about 5 months. Few months ago noticed the air con wasn't blowing cold. Not sure if it ever had to be honest, never really checked it until weather heated up.

Had it regassed, think the chap said it had not really lost much anyway and no signs of leaks but he did it anyway.

Seemed to fix the issue anyway, blowing nice and cold so I was happy.

This last weekend noticed it was pretty poor again, slightly cool at best, definitely not cold.

Unless I do have a leak it shouldn't need regassing so I'm wondering if there's a different underlying issue.

I have vcds so hooked that up but not showing any faults.

I had a bit of a play looking at measured values and showed 6 bar of pressure in the system and the compressor was spinning, can't recall exactly but over 1000rpm at idle and picked up with reving the engine.

That's about as far as my diagnostic skills go!

Has anyone got any thoughts on other things I could check via vcds or by other means before I book it in somewhere to be looked at?

Thanks
Steve

 

[mmi]

Please post full VCDS Auto-Scan and blockmap of 08-Auto HVAC so that we can see what's available

How-to-blockmap:

VCDS -> Applications -> Controller Channel Map ->

Tick/fill boxes as above and hit Go

VCDS Flashes screens for a moment (when finished hit "Done, Go Back") and there will be file blockmap-08-... in folder C:\Ross-Tech\VCDS\Logs\....

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Actually I would like to have a few "blockmaps" with AC set to 20C (or max cool), blower at (minimum) 2 - just keep the settings.

Just hit "Go" for each step below - may take it for a drive after step 3.

1) Ignition ON - engine off​

2) Engine on tick over - 30 seconds after start up​

3) At 1 minute​

4) At 5 minutes​

5) At 10 minutes​

6) At 15 minutes​

7) At 20 minutes​

Each of them will be in a separate blockmap-08 -file.

 

[Scut]

Ok great thanks, will do that later today and post back.

 

[Scut]

OK, here is the autoscan..........

And here are the blockmaps.......

 

[Dellmassive]

the inside air temps are defo high . . .

29C inside and 23C vent temps.

and No Codes stored at that point.






might need @mmi to cross reference that data to a known good AC operating data set?

ill upload mod #08 - blocks tomoz if needed @mmi ?

 

[mmi]

Thank you very much
Yes, it's not cooling much - but that's we already knew. Just a bit - outside temperature approx. +19C and at evaporator +16C. Should be +2..+4 (mine does).
The refrigerant pressure (4 bars) is much lower than mine (9...14 bars). But mine was recorded at +28C, so I'll check mine again at similar temperature (tomorrow)
Also reported compressor load is just a fraction of mine.
I'll put all the data into one table tomorrow...

What sticks out is that engine's coolant fan doesn't run at all - I think without it running the AC can't do much.
Meanwhile, can you run VCDS Output Test under 01-Engine to HEAR it's working? (IGN ON, engine not running)

@Dellmassive - definitely appreciate if you have a chance to do the same!

 

[mmi]

the inside air temps are defo high . . .

29C inside and 23C vent temps.

and No Codes stored at that point.




might need @mmi to cross reference that data to a known good AC operating data set?

ill upload mod #08 - blocks tomoz if needed @mmi ?

Here's just a glimpse of mine....

 

[Dellmassive]

What sticks out is that engine's coolant fan doesn't run at all - I think without it running the AC can't do much.
Meanwhile, can you run VCDS Output Test under 01-Engine to HEAR it's working?

- good advice that. ( run engine fan test )

@Dellmassive - definitely appreciate if you have a chance to do the same!

- ill get tomorrow

 

[Scut]

Thanks very much both, I'll run the engine fan test later today and report back.

 

[Pauly]

Surprised theres no faults logged, even if the van cant see any faulty components you would think it could figure out a lack in temp drop between sensors and know theres an issue

 

[mmi]

Thanks very much both, I'll run the engine fan test later today and report back.

Were you happy with the cabin temperature yesterday? At first glance it looks like the AC was happy providing what you requested???

Can you redo the first 10 minutes blockmaps (just steps 2-5) but ALL the temperature controls at max COLD and blower at 4 (6 is the max??) - so we can see what's the full cooling capability?

After the step 5 (engine still running - on idle), could you please change the "Single controller address" to 1 (=Engine) and run a blockmap for it too.

 

[Scut]

OK, so yesterday - no - wasn't happy with the cabin temperature - outside the blockmaps recorded yesterday I did turn it down to max cool and no change to cabin temperature or blower output temperature.

I've just redone the blockmaps as requested (max cool, blower on 4 of 6, van was idling throughout) - they are attached. Also attached is the engine module block map.

I've also just done the fan output test in the engine module which seems to work - ramps up to high speed for 3 or 4 seconds then winds down, then ramps back up for 3 to 4 seconds and back down and just keeps repeating that cycle (I assume this is normal that it is cycling up and down in speed for that output test).

 

[mmi]

Here's a snapshot highlighting some strange differences in performances (compared with mine (Climatic)).



It looks like your compressor doesn't do much (see compressor current vs. achieved pressure vs. performance (temp at evaporator)).

The highest pressure I found in my logs (not here) has been (at +28 ℃ outside temperature) 14.6 bars (compressor current 0.82 A, engine idling).
Lowest temperature seen at evaporator 1.3 ℃ (today using MAX COLD).

---

Attached a file where your data from yesterday and today is compiled into one file.

Also attached my data from a journey today in similar temperature (+19 ℃) - it started with "normal +20 ℃" - setting, and later MAX COLD was turned on. My AC is Climatic, so missing left/right individual adjustments etc. and related data.

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Just a note about logged data - the IDE00983 Inside temperature doesn't very well correlate actual cabin temperature (or actually how it feels to have a cool breeze)
E.g. in attached graph from a 13 minute drive on a hot day - it was hot outside but very comfortable after two minutes in the cabin although the inside temperature sensor shows rather hot temperatures.

 

[mmi]

I've also just done the fan output test in the engine module which seems to work - ramps up to high speed for 3 or 4 seconds then winds down, then ramps back up for 3 to 4 seconds and back down and just keeps repeating that cycle (I assume this is normal that it is cycling up and down in speed for that output test).

Yes - that's correct. Proves very much that engine coolant fan is not the cause.

 

[Pauly]

I love it when @mmi goes all graphy
100% geek mode

 

[mmi]

I love it when @mmi goes all graphy
100% geek mode

"Graph is worth a thousand words"

 

[Scut]

Thanks @mmi appreciate you taking the time out to look at the data and compare.

Certainly some significant differences.

Suppose it's good that the fan test was OK, so I don't need to concern myself about other issues outside of poor air con at the moment.

I'm not sure what else to make of the data now though to be honest, no smoking gun so to speak as far as I can see.

Interesting that my fan is not kicking in with the air con, I wonder if that's a cause of the problem, or a symptom due to some other part of the system not functioning as expected.....

 

[Scut]

Just looking at the data again @mmi

Concentrating on the refrigerant pressure for now.

My block map from Thursday without engine running was 2.4 bar. Increasing to 4 to 6 with engine running depending on temperature.

I can see your pressure with engine running is quite a lot higher.

It would be interesting to see what yours is without the engine running once everything has settled down as I assume the high and low pressure sides will equalise after a while and the reading will effectively be the charge pressure of the system.

If this static pressure is a lot higher than mine then it might indicate I'm low on refrigerant again and maybe I have a leak somewhere.

Other causes I can think of for lower pressure when running are obviously a compressor problem, but also maybe an expansion valve sticking open (I don't know where these are or if I might have two with me having the rear hvac unit as well).

All 3 of these (low refrigerant, faulty compressor and stuck open expansion valve) might explain my problem and the lower load being seen at my compressor.

Is this making sense?

Thanks
Steve

 

[mmi]

It would be interesting to see what yours is without the engine running once everything has settled down as I assume the high and low pressure sides will equalise after a while and the reading will effectively be the charge pressure of the system.

From yesterday - just ignition turned on (engine not started) - as step 1 above.
-morning (+13 ℃) after 14 hour rest - 4.0 bar.
-afternoon (+19 ℃) after 8 hour rest - 4.6 bar
EDIT:
26.7 afternoon (+28C) after 8 hour rest - 6.6 bar

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Another interesting difference in the statistics - the mileage on my van is just slightly less than yours....

These "Interior temperature difference to specifications" and "Blowout temperature difference to specifications" seem to a kind of states before AC reaches balance ("Stop release" in logs). I don't know what conditions accumulate these - they look like counters for "condition not reached"

		Scut​	mmi​
IDE03010-MAS02802	Number of prevented stop processes-Interior temperature difference to specifications	1297​	40​
IDE03010-MAS02803	Number of prevented stop processes-Blowout temperature difference to specifications	3408​	28​

 

[Scut]

Thanks again @mmi.

Checked again this morning with ignition on only. 18 degrees and 2 bar.

If yours is normal then mine is running with 50 percent pressure so looking most likely I do have a slow leak from somewhere.

This might explain why it worked fine after being regassed a few months ago.

They did a pressure check at the time before refilling which came back OK but if it takes a few months to lose pressure maybe the 5 or 10 minute check they did wouldn't detect it.

I've seen some leak sealing regas/refil options on the net but don't fancy putting that in the system in case it causes other problems down the line.

Think I just need to get it booked in somewhere to look at. Anyone any suggestions in the Hull area other than main dealers?

No sense having a regular regas again if it's just going to do the same in a few months.

Don't know why the fan doesn't kick in though......