Air Con: Replacing the Evaporator Temperature Sensor

[theseriojca]

Hello

Another question on my still non-working Air Con - VIDA has pointed towards a non-working Evaporator Temperature Sensor. Looking into replacing it, it seems to be a very labour intensive job (removing the dashboard, steering wheel and the whole Climate Control Unit). The sensor itself is only 13 Euros without delivery (part number 30665118, in case it's useful for anyone), but to get to it would take a whole day of garage labour.

Now, I'm more than willing to give the Dashboard and Steering Wheel removal a shot in my father-in-law's warm garage, but what's putting me off is that VIDA says the CCU needs to be removed. That involves a lot more work under the bonnet, pipework, refrigerant knowledge and so on and so forth and I don't think I want to mess with that.

The question:

will I be able to access the faulty sensor and replace it just be removing the Dashboard and the Steering Wheel, or do I actually need to remove and pull back the CCU for access? Has anyone done this before? The VIDA picture is not very clear on where the sensor actually is located!

This is especially frustrating seeing that on LHD cars it's as simple as remove a piece of trim and voila, direct access!

Any help appreciated, thanks in advance,

Serge

[gmonag]

Removing the CCU is very simple - 2 screws

https://www.youtube.com/watch?v=glvHx2bX5d0

No need to remove the steering wheel or pipework etc.

[cheshired5]

Originally Posted by theseriojca

non-working Air Con - VIDA has pointed towards a non-working Evaporator Temperature Sensor.

How has it pointed you towards this?
What is the exact fault code(s)?
Have you viewed the live evaporator temperatures in CCM >Parameters?

On a stone cold car with ignition only on, it should read ambient temperature within a couple of °C
With engine on, cabin temperature set on both sides to 21°C and climate set to Auto (AC on), the evaporator temperature should fluctuate between around 6°C to around 12°C

[kdst5]

There is a fairly long thread on the V70/XC70 00-07 forum about this https://www.volvoforums.org.uk/showt...erature+Sensor
Might be worth having a look through as the XC90 shares a lot in common with the V70/XC70.

Also could you not just plug in the new sensor without putting it in the correct position just to see if the air con starts working up? I am assuming the sensor is there to turn off the compressor when the evaporator is close to freezing up therefore if the sensor is hanging in free air then it should start to work? Obviously don't try it for to long or the evaporator will freeze up.

[theseriojca]

Thanks for all the replies, will try to get more info tonight when at home

[theseriojca]

Originally Posted by gmonag

Removing the CCU is very simple - 2 screws

https://www.youtube.com/watch?v=glvHx2bX5d0

No need to remove the steering wheel or pipework etc.

Thanks Greg, I think you mean just the front bit with the air con and media controls, but VIDA says I need to remove the whole Climate Control Unit, ie the big hunk of equipment behind those controls. Appreciate your reply but, thanks!

[theseriojca]

Originally Posted by cheshired5

How has it pointed you towards this?
What is the exact fault code(s)?
Have you viewed the live evaporator temperatures in CCM >Parameters?

On a stone cold car with ignition only on, it should read ambient temperature within a couple of °C
With engine on, cabin temperature set on both sides to 21°C and climate set to Auto (AC on), the evaporator temperature should fluctuate between around 6°C to around 12°C

Hi CheshireD5, the garage told me the sensor needed replacing at the last service in June, which I guess is my biggest clue.

The code that VIDA gives me is CCM-003 Evaporator Temperature Sensor Signal Too Low.

I have not viewed the Parameters yet, but will try later tonight, although it being 4 degrees outside, is it even worth it? It's not meant to go above 10 any soon either, is that a dead end just now? I'll check if it reads anything anyways, now that I know I can do that

Thanks for your reply, really appreciated,

Serge

[theseriojca]

Originally Posted by kdst5

There is a fairly long thread on the V70/XC70 00-07 forum about this https://www.volvoforums.org.uk/showt...erature+Sensor
Might be worth having a look through as the XC90 shares a lot in common with the V70/XC70.

Also could you not just plug in the new sensor without putting it in the correct position just to see if the air con starts working up? I am assuming the sensor is there to turn off the compressor when the evaporator is close to freezing up therefore if the sensor is hanging in free air then it should start to work? Obviously don't try it for to long or the evaporator will freeze up.

That is a great thread, thanks a lot, kdst5, I hope the internals of the XC90 and the V70 are similar enough, I'm willing to give this a try if yes! I'd be happy to post some pictures and guidelines as well, just need to get my hands on the sensor first and take a good look under the dash.

Just to check, when you say 'plug in the sensor without putting it in the correct position', that's pretty much just leaving it dangling in the air?

Also, how do I get to the wires? And how do I know if it is the Purple and the Brown wire, like on the V70? There's a mention of a 'terminal block', is it one of the green plugs at the back of the Air Con Control panel? Where can I get that diagram for the XC90?

I've attached the pictures from the V70 mod thread, do you know if the XC90 would be similar enough?

Thanks a million for your advice!

Serge

link to green plug of the XC70

Modded Evaporator Casing

The Proposed Hole Location

[oragex]

As above, I wouldn't worry about the sensor at this point - it might be bad, but you may have something else going on that needs be fixed in the first place. The evap sensor will not prevent the A/C from running. In fact, when this sensor fails, it will cause the A/C to run without cycling, resulting in a frozen evaporator unit and little air off the vents.

Was the A/C working this summer ? I think the compressor will only work if the outside temp is above 10C or so.

[kdst5]

Yes I was thinking leave the sensor dangling in the air just to test it is working but that does assume it's easy to get the connector which I don't know.

Oragex, are you sure "The evap sensor will not prevent the A/C from running"? Could it need to be within certain parameters or it assumes it faulty and therefore stops it working?

I think when I was on the P2 V70 forum it was always said 5 degrees outside temp was the cut off point for the air con.