Trev, I’m not sure how the Climatronic and the ECU talk to each other. Are you saying either takes control via the bus and shuts off the compressor but only one would know why? So depending what you look at to diagnose the problem you may see a code or not?

 

David

Its all done by CAN-BUS, if the engine is under high loads the engine ECU sends a signal via the CAN controller to the HVAC ECU to turn off the A/C, you wont notice it but it will if required to do so.

 

If you do get a shut off code, that's what is shutting off the compressor, if for example there is no code ie 0, this means the compressor is working, but if still no A/C, then the compressor is not working even though it should be according to the code read.

 

Is there any one near to you that has VDCS?, and knows how to use it?, that will tell you all the shut off codes and what they mean, like I said shame you don't live closer.

 

Tomorrow I will try to find all the shut off codes and put them on here.

 

Hope this helps?,

 

Trev

3 hours ago, Aston_Bodger said:

 IDE00965   Compressor shut-off requirement Compressor active: no shut-off condition is present 

 

I think we have the smoking gun there, its no good looking for a voltage it don't work that way I have found out.

 

You should have a compressor shut off condition of some sort, the engine ECU can do it too, when high revs are required, normally this will be 0 if its working. Pressure seems fine to me, its about what I had when mine was not working, that's the first thing I checked.

 

Do you know anyone with VDCS?, that will tell you straight away.

 

Trev

 

Thank you for the help Trev

 

I do have VCDS. That's what I used to log those parameters. 

When I scan the module it does not come up with any errors.

Is there anything else I should be doing with VCDS?

Aston_Bodger: Thanks Trev, I don't know anyone local with a VCDS unfortunately but I've got the car booked in Monday morning with an auto electrician so will see what he says then. One thing that I'm not clear on... is the HVAC ECU and what I'm calling the Climatronic one and the same thing? If they are, from what you said if the Engine ECU sent a compressor stop signal to the HVAC ECU presumably I would see that on the Climatronic Onboard Display (even without a VCDS to help)?

9 hours ago, Squible said:

 

Thank you for the help Trev

 

I do have VCDS. That's what I used to log those parameters. 

When I scan the module it does not come up with any errors.

Is there anything else I should be doing with VCDS?

Mine did not have any errors either, so I went back to basics, a lot of techs rely on laptops etc too much now, I'm old school, checked all the connections first then did continuity then worked it out by deduction in the end.

 

Trev

2 hours ago, m0ezp said:

Aston_Bodger: Thanks Trev, I don't know anyone local with a VCDS unfortunately but I've got the car booked in Monday morning with an auto electrician so will see what he says then. One thing that I'm not clear on... is the HVAC ECU and what I'm calling the Climatronic one and the same thing? If they are, from what you said if the Engine ECU sent a compressor stop signal to the HVAC ECU presumably I would see that on the Climatronic Onboard Display (even without a VCDS to help)?

Yes the HVAC controller the bit with the knobs on, that is an ECU in its own right and communicates with the rest of the system. They all "talk" to each other though the CAB-BUS network.

 

Have a look at shut off code 12 below.

 

Hope that clears it better?

 

Trev 

Edited 19 May, 20188 yr by Aston_Bodger
extra line added

As promised here are all the shut off codes, which might help,

 

0 = Compressor on (no shut-off requirement of the A/C compressor detected)

1 = Compressor off (refrigerant pressure was or is too high)

2 = Compressor off (blower motor circuit)

3 = Compressor off (refrigerant pressure was or is too low)

4 = Compressor off (display not currently intended)

5 = Compressor off (no engine start or no engine speed detected)

6 = Compressor off (A/C system switched off, ECON-mode activated)

7 = Compressor off (A/C system switched off, blower switch in position 0)

8 = Compressor off (outside temperature was less than 1.5°C and is still less than 2.5 °C)

9 = Compressor off (display not currently intended)

10 = Compressor off (Low voltage)

11 = Compressor off (display not currently intended)

12 = Compressor off (shut-off request from Engine Control Module (ECM) via CAN)

13 = Compressor off (voltage supply terminal 30 too high)

14 = Compressor off (Evaporator Temperature)

15 = Compressor off (display not currently intended)

16 = Compressor off (activation A/C Compressor Regulator Valve -N280- implausible)

17 = Compressor off (no signal or implausible signal from High Pressure Sensor -G65-)

18 = Compressor off (engine speed too high at standstill)

19 = Compressor off (shutoff request from Vehicle Electrical System Control Module via CAN)

20 = Compressor off (refrigerant loss-currently V8 Touareg only)

21 = Compressor off (Outside Temp < 2 degrees C, without recirc mode on)

22 = Compressor off (Outside Temp < 2 degrees C, Inside Temp. < 10 degrees C)

 

Trev

Thanks Trev, yes that clears my confusion. So if there isn't a compressor code showing when I look at the Climatronic display the HVAC isn't aware of a problem and it would be aware via the CAN-BUS if the Engine ECU found one. Also I noted Squible's VCDS output referred to the HVAC section. 

 

This tells me that on Monday the auto electrician won't find any relevant compressor error codes although he might find something else I'm unaware of of course.

 

David

Thanks Trev for the cut-off codes. Yes I've seen compressor code 5 when the engine isn't turning over which is correct mine is 0 when the engine is running and I haven't seen any other codes. I did find the fans running slowly this morning after a drive too.

3 hours ago, m0ezp said:

Thanks Trev, yes that clears my confusion. So if there isn't a compressor code showing when I look at the Climatronic display the HVAC isn't aware of a problem and it would be aware via the CAN-BUS if the Engine ECU found one. Also I noted Squible's VCDS output referred to the HVAC section. 

 

This tells me that on Monday the auto electrician won't find any relevant compressor error codes although he might find something else I'm unaware of of course.

 

David

Hi David, (now I know your name LOL),

 

If the shut off code is 0, then as far as the HVAC ECU is concerned its working, but  there is no diagnostic fault code for this issue which I find a bit strange but hey I didn't write the programme.

 

If your auto electrician has VDCS or equivalent, he will get the same code 0.

 

Let me know what happens on Monday please.

 

You can take a copy of the shut off codes too that might help him?, we will see how good he really is LOL:)

 

Trev

Edited 19 May, 20188 yr by Aston_Bodger

Yes Trev, I'll probably make a right pain of myself on Monday if possible. Its at a garage so there might be H&S restrictions on how nosy I can be with what he's up to but I'll make it clear I want to know as much about his findings as poss and will report back

 

David

Sometimes if you ask nicely they do let you in to see what they have, I tried to change my cam belt one year, got all the stuff and nearly got the belt off and I could not time it up, so it all went back together and I asked a local indy to do it for me, while there I asked if I could be cheeky and have a peek where the locking bits went, no problem I will give you a shout when he has them in, so I does happen sometimes. if you don't ask you don't get, they can only say no cant they?.

 

Trev

Hi Trev,

 

Ha ha, it reminds me of deciding I could tweak the dwell angle in a distributor on a Golf about 30 years ago. It wasn't broken before I started but it was when I'd had a bash!   Yes, I'll try to get as much access as I can!

 

David

Hi David,

 

I can set dizzys and carbs up by ear, they are easy as you like not like fuel injection, they are something else, luckily I was dragged up with fuel injection and can sort out most things without a computer telling what's wrong with it.

 

Trev

Hi Trev,

 

Yes, I like to understand what's under the bonnet even if I'm not getting the grime under my nails; computers do complicate matters a lot!

 

So, the Occy is in for a new compressor! The garage is mowed out but at worst it will be Wednesday before I get it back.

 

I quite liked the auto electrician and was happy with his diagnosis - paid £60 cash. He was using VCDS and I couldn't get close enough to see the detail on his laptop but he did talk through what he was doing. He confirmed that there were no diagnostic codes (as we thought from looking at the onboard diagnostics from HVAC) and that pressures were right. Next he plugged a device into the pulse-wave output of HVAC to the compressor solenoid valve and that showed the valve was receiving signals okay. He did a bit of twiddling the Climatronic controls whilst checking VCDS output and ruled out fan, condenser, expansion valve and evaporator. No temperature difference was evident between the input and output of the compressor so he said "its either the 'internal clutch' or the solenoid valve, either way on a 2007 compressor, you need a new compressor".

 

The garage estimates 1.8 hours labour and got a price for a Hella compressor BFK-351-322-741 at £186.84+vat. Compressor was delivered while I was waiting for a taxi so I'm not complaining if that sorts me out

David

 

p.s. I'm over the moon with the garage. They got mine done much before expected so I've now got a cold car after new compressor fitted!

 

Working Air-Con data

I took some more data from the Climatronic HVAC onboard diagnostics to show what a fixed air-con looks like on a hot day with engine fully warmed up and car stationary. Figures in brackets are comparative before the compressor was fixed...

 

Various temps:-

04-0 Temp External = 23.5 C  (20.0)

01-1 Temp External CANBUS = 31.5 C  (25.0)

08-0 Right side actual temp screen = 6.6 C  (35.6)

08-1 Footwell = 15 C  (35.5)

08-2 Vents = 6.6 C  (35.6)

 

Evaporator:-

10-0 Evaporator temp = 5.3 C (34C)

10-1 Liquid refrigerant pressure = 12.0 bar (4.0<7.6)

Evaporator is now chilly rather than basking in the sun and liquid pressure should be up at the 11-12 mark

 

AC Compressor:-

11-0 Power set-point mA = 69.5 (82.0)

11-1 Power actual mA = 70.0 (82.0)

11-2 Power max mA = 82.0 (82.0)

11-3 Compressor PWM = 68.5 (92)

11-6 Compressor code = 00 (00)

Presuming the internal clutch in the compressor had crumbled or the solenoid valve had stuck, the compressor was eating all the power that it could get before at 82mA so actual power equaling set-point probably means too much friction in the compressor and time to get a new one. The PWM down at 68.5 presumably means that the HVAC is happier to modulate the compressor at a lower rate as its now getting better data back.

 

A pity that the Compressor codes from HVAC and VCDS were zero and that didn't help diagnosis. Thanks Trev for the tips that made sense of it all

 

David

 

Hi David,

 

Good to see you got your car back so quickly, and my diagnosis was spot on.......again!!

More likely to be the valve stuck somewhere along it's travel, there is no clutch in these compressors, they run all the time, even on "eco", still runs at 2% if memory serves correct.

 

This what the forum should be about, helping each other with problems and how to fix them.

 

Yeah shame no fault codes, but there again, it's not part of the CAN-BUS network.

 

Computers do make things a bit easier, but not every time as we have found out just.

 

If you need any help with anything else, you know where to find me

 

Trev

Thanks so much Trev, yes that's what the forum is about.

Ah yes I remember now about the no clutch - it must have been the valve then as there's nowt much left otherwise

Thanks again,

David

Hi David,

 

You are very welcome.

Glad I could be of assistance helping forum members out.

It's usually the valve that goes, other than a stone taking the condenser out, cos of the maoosive slats that they decided to put up front, that's why I have put mesh in front of mine.

 

Trev

I never thought of mesh to protect the condenser/radiator. What a good idea Trev, I’ll have a look at doing that

Many thanks

David

Hi Trev, no time like the present. It's surprising how vulnerable the condenser is when you think about it so I got 2' x 1'6" galv mesh (1/4" holes) and I've tied it in front of the condenser. I tied it into the bottom of the grill with cable ties (you can't see them) so it stands away from the condenser quite a bit at the bottom. Not much I could do at the top other than thick tape on the sides to stop chafing and tie in with cable ties.

Hi David,

 

I saw some mesh in B&Q, I think its aluminium and all I did was drill holes in the slats and cable tied it to them, top and bottom, had to leave a gap for the bonnet release, but he ho is stopped the stones.

 

 

Trev

 I attempted to put I ggtrhfth  

My attempt to put the aircon into debug mode didn't go well

That looks normal once it’s finished recalibration or at least what I was getting.