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Discussion Starter #1
Hello Guys,
I have been tinkering on my fathers Jaguar XF (x250) (3.0 D Salooncar, MY2011) lately. A huge part of its flaws was related to an faulty BCM due to water ingress from the washer Pump.
(Sadly our dealer was not aware of this issue).

One of the things that has not been fixed yet is his A/C.
It only starts cooling after several minutes of driving/idling. Usually this takes about 10 minutes.
Coolant was refiled by an specialist lately, who also checked the pressure in the System. According to him everything was fine. But he also found the same issue, the car only started blowing cold air after several minutes.

A few more informations that i have found:
- The automatic starts blowing like crazy when you start the car. It slows down if you raise the targtet temperature.
-it is not as cold as it used to be after it started cooling.
-Magnetic clutch seems to be engaging (Soundwise)
-The interiour Headlight is not working properly( Is there an theremometer in there?)
-The engine Fan is NOT running if the A/C is switched on.

The last point is afaik necessary to produce cold air when the car is not driving. But this does not seem to be the sole issue as it would normaly cool if you are driving at +100kph, wich it does not in the first minutes of the ride.

At this point I am pretty guesless on what could cause this Problem, so I would be gratefull on any idea, or way to test single components to narrow it down somewhat.
 

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Hi Phil. Welcome to the forum.
A very common issue with AC in the XF (and other models) is something called the DPS (direct pressure sensing) valve. In fact there is a Jaguar Technical Bulletin about it (JTB00380v7). See attached.
If this is what your problem is, it is a relatively quick and inexpensive garage/dealer fix to replace it.
 

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Discussion Starter #3
Thank you for the quick Answer OBC! Is there a way to test if it is really the DPS?
The climate technican (Bosch service) said all pressure readings were allright.

Otherwise this would definitely be worth a try. 120- 150€ for the parts + how much time in the garage? Should not be more than 1-2 Hours I guess?
 

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As this is essentially a pressure switch which amongst other things tells the condenser fan to run, it doesn't actually affect the frig pressures so they will look OK in a snap-shot. But I don't know how to test it. Sorry.
 
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The climate technican (Bosch service) said all pressure readings were allright.
As I understand it, the only accurate way to check if the refrigerant level is correct is to draw it all out and weigh it.
Admittedly it wasn't a Bosch service agent for me, but in my other car I was told the pressures were fine - however the air con specialists found it was down to ~30% charge.
 

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Discussion Starter #6
Hello Pete,
The aircon was evacuated, vakuum-tested and was only refiled later.
So I am pretty sure there is enough refrigerant in the system.

What really makes me wonder is that the cooling fan never seems to run. But the car has never shown any overheat warnings for the engine.
The missing coolant temperature gauge is really a pain in the butt in this case.
 

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Hello Guys,
I have been tinkering on my fathers Jaguar XF (x250) (3.0 D Salooncar, MY2011) lately. A huge part of its flaws was related to an faulty BCM due to water ingress from the washer Pump.
(Sadly our dealer was not aware of this issue).

One of the things that has not been fixed yet is his A/C.
It only starts cooling after several minutes of driving/idling. Usually this takes about 10 minutes.
Coolant was refiled by an specialist lately, who also checked the pressure in the System. According to him everything was fine. But he also found the same issue, the car only started blowing cold air after several minutes.

A few more informations that i have found:
- The automatic starts blowing like crazy when you start the car. It slows down if you raise the targtet temperature.
-it is not as cold as it used to be after it started cooling.
-Magnetic clutch seems to be engaging (Soundwise)
-The interiour Headlight is not working properly( Is there an theremometer in there?)
-The engine Fan is NOT running if the A/C is switched on.

The last point is afaik necessary to produce cold air when the car is not driving. But this does not seem to be the sole issue as it would normaly cool if you are driving at +100kph, wich it does not in the first minutes of the ride.

At this point I am pretty guesless on what could cause this Problem, so I would be gratefull on any idea, or way to test single components to narrow it down somewhat.
As John mentioned, if you are confident about gas in the system, it’s very likely the DPS “valve”. it’s not a sensor, it’s a control valve that sits on compressor. The diagnosis steps are in the workshop manual and bulletin that John shared. You can only assess this with SDD. On this car the A/C compressor clutch doesn’t switch on/off like older cars unless there is a problem or you switch a/c off from the climate menu.
Instead DPS valve regulates the flow. If it sticks open/close or doesn’t travel smoothly the gas flow won’t match the need. While stationary you need more gas flow because compressor rpm drops and when on the move it restricts the flow. Since your mechanic has checked the pressure, your gas and compressor should be fine. Next ones are DPS valve, A/C stepper motor or cabin humidity/temp sensor.
you can read more about it by searching ac compressor control valve. DPS Valve is a known fault while other two could be tested.

You probably don’t have access to SDD so if you have below symptoms the problem should be DPS valve.
  • no cold air when stationary.
  • ac blows warmer air under cold settings.
  • ac works normal in colder days but not in a hot day.
  • in a hot day, Ac fan speed doesn’t drop.
the valve could be sticky and only behave abnormal when is cold. Also it could be just a loose connector.
 

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Excellent explanation Hamed, full and easily understandable, thanks for that interesting read!! :cool:
 

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Discussion Starter #9
Thank you Hamed, really a great explaination.
I will check the connector myself, and if this is not the reason for the faulty climate behaviour we will have the DPS-Valve replaced at the climate specialist.
But, how could I test the A/C-stepper valve and the Cabin humidity Sensor?

P.S. At this point I have to admit you Guys are great! In the german forum I propably would have waited for days to get this far.
 

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Thank you Hamed, really a great explaination.
I will check the connector myself, and if this is not the reason for the faulty climate behaviour we will have the DPS-Valve replaced at the climate specialist.
But, how could I test the A/C-stepper valve and the Cabin humidity Sensor?

P.S. At this point I have to admit you Guys are great! In the german forum I propably would have waited for days to get this far.
Unfortunately I only know how to check it using SDD that has a procedure to reset the calibration. Having said that I am assuming your AC works and it’s only very weak. Otherwise a failing refrigerant pressure sensor could also stop compressor from kicking in. Again only SDD or a similar diag tool can read them.
I don’t know anyone in Germany with SDD but you might find someone here or in German forum offering help. It only takes few mins to spot problem when you have access to data. If you decided to go ahead with DPS valve replacement be aware that it is a generic part shared across manufacturers so you might be able to find one made for ford or vw group under £20 while JLR branded ones are +£65. I wish you had access to SDD so you could say for sure what’s faulty. You have to depressurise the system to change the valve otherwise a competent DIYer can do it. if you find somewhere with the right equipment for saving the gas, You might be able to avoid paying for regasing the system. Or if you find a JLR specialist they can identify the problem. It’s a very clever system.It have control over everything. Even it can manage the compressor load to increase fuel economy.

if you were interested in SDD these are examples of a cable that you need:
3-1
I have this one
You might be able to find them anywhere else. Even on the Bay
 

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Discussion Starter #13
It worked!
The cat went to climate specialist today and he changed the DPS. After work we picked the Jag up and finally had the joy of an working A/C again.
In the end it was no inexpensive fix but my father is still happy with it.
My Dad was rather impatient and orderd the original Jag part from the UK wich was about 140€ with shipping.
The Bosch service said the change was a real pain in the ass and it took him about 3 hours to change it. In the end his hill came out to be 320€. So plus the 100€ for the first regassing the total cost was 560€.

And it would haven been more without your good advices! So a special thank you to @OBC John and @hamedhbb !
 

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Good result Phil, thanks for coming back and letting us know.. appreciated. (y)
 

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Good news, Phil. And thanks for posting the update.
 

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It worked!
The cat went to climate specialist today and he changed the DPS. After work we picked the Jag up and finally had the joy of an working A/C again.
In the end it was no inexpensive fix but my father is still happy with it.
My Dad was rather impatient and orderd the original Jag part from the UK wich was about 140€ with shipping.
The Bosch service said the change was a real pain in the ass and it took him about 3 hours to change it. In the end his hill came out to be 320€. So plus the 100€ for the first regassing the total cost was 560€.

And it would haven been more without your good advices! So a special thank you to @OBC John and @hamedhbb !
Thanks for the update. Just on time so he can still enjoy it this summer!
 

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Good news, and thanks for coming back to tell us, you might be surprised how many don't.
 

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Mine seems to be suffering from very similar symptoms.

It's going to Swallows today for a re-gas to see if it cures the problem.

If it doesn't then at least I'll know what wants replacing.

Sent from my SM-G975F using Tapatalk
 

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Here's hoping Jay.. do let us know the outcome.. (y)
 

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Here's hoping Jay.. do let us know the outcome.. (y)
Will do Pete.

I was chatting to a refrigeration engineer in work yesterday and he seems to think a re-gas will hopefully sort it. It seems pressure is vital in making the system work properly and if it drops it can cause poor performance.

I've properly picked the best day of the year to get it tested!

Sent from my SM-G975F using Tapatalk
 
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