Air conditioning faults

[gordj65]

I have the above fault codes reading out on my diagnostic machine. They all relate to " Circuit Defective" .  for the servomotor and air recirculation flaps. Can anyone tell me is this a circuit board issue, a wiring issue or something else. Any information on where I might need to look as well would be handy. just trying to save myself some time if someone has already had to fix something similar.

cheers

Gordon

[mrmike]

Does the A/C work? There are some codes that come up on mine but they are irrelevant, Maybe they were for earlier models etc.

Cheers

M

[NumeatonGraham]

Hi Gordon,

did you get this sorted.

I get B1263 the same as you when i plug in my scanner.I reset the code.

My aircon has just started to give warm air only and it goes into the garage on Tuesday as we suspect the DCCV,has failed.I decided to checkout the DCCV first as these are known to be unreliable,then checking the

wiring to it as these can get brittle.If no joy i will check the ccm module and send it away for the upgrade.

I believe this route to be the most economical financially initially.I have tried to get the Bosch DCCV but without success so i will put a cheaper one in and look to change asap.

Graham

[mrmike]

Check the votages going to the DCCV, I can't remember whether they go high or low to stop the hot coolant. Obviously on cool there must be no hot coolant. I changed the DCCV  first for a cheap one, but it wasn't the problem. It is still going fine after 3 years. There is an excellent guide which I posted the URL to on here 3 years ago. Unfortunately my problem was the A/C compressor, Still it could have been worse!

The system is quite complicated, With the help of the guy who wrote the guide (Carl, I think, from the US), and a couple of weeks of comms between us to eliminate all possible faults I had a Compressor test done by a Specialist A/C company here in Spain and they confirmed a tired compressor. A real !Removed! of a job to change on the diesel, it comes out from the top unlike all the other models and the manual is also wrong on various steps.

[mrmike]

Here tis- Karl...... https://www.jaguarforums.com/forum/s-type-s-type-r-supercharged-v8-x200-15/epic-troubleshooting-guide-climate-control-how-185002/

Title

An Epic Troubleshooting Guide for Climate Control HOW TO

[NumeatonGraham]

Thank you Mike for pointing me to the guide.

[LairdScooby]

3 hours ago, mrmike said:

Check the votages going to the DCCV, I can't remember whether they go high or low to stop the hot coolant.

There should be a permanent +12V feed to both halves of the DCCV, the AC control Module takes the output low (and cycles it using PWM) to close the valve(s) and the module output is connected to the other side from the +12V feed - in other words when the valve is powered, it closes.

Had a similar problem on mine when i bought it, turned out to be a fusebox problem..........

[mrmike]

I still have a very slight problem which came to light when I was going through the fault finding, the passenger side is always 3deg C  higher than the setting. At Max cooling the CCU is sending a short pulse, An analogue meter shows a short kick at regular intervals and I guess that at whatever Temperature is set the passenger side valve gets a slightly wider pulse. My wife doesn't notice and as far as she is concerned it goes up and down as requested. So no need to change anything. BTW the sensors were all Ok. If I had had a circuit diagram for it I would have investigated, I did think of connecting the gate of the passenger side Fet to the driver side Fet so the control would have been from the driver side.

[LairdScooby]

54 minutes ago, mrmike said:

I did think of connecting the gate of the passenger side Fet to the driver side Fet so the control would have been from the driver side.

You can set both to Low and then just use the drivers control to control both sides at the same temperature, saves fiddling about with FETs etc.

[mrmike]

Not True!

It was still  3 degs higher on the passenger side. I took no notice of the reading on the screen, I measured the temperature at the vents. On the screen they were both 17C. At the Connector on the drivers side the short pulses could be seen on an analogue meter that were controlling the passenger side of the DCCV. They were were not present on the drivers side connectors.

The problem was down to the CCU.

Anyway it works keeping us cool even when it is nearly 40C outside and it gets cool within a couple of minutes on Low even at 50km. (thanks to the Compressor mod)

 

[LairdScooby]

1 hour ago, mrmike said:

The problem was down to the CCU.

1 hour ago, mrmike said:

Not True!

It sounds very much like the ECU is doing exactly what it's told to do - you need to investigate the sensors for the two sides (driver and passenger) and clean their housings as it's possible the drivers side is colder than it should be rather than the passengers side being warmer than it should be.

Usually they are NTC thermistors so you could fudge the temperature with either a series resistor or a parallel resistor but i would suggest cleaning both sensors and their housigns first and then swap the sensors from one side to another to see if the fault moves.

[mrmike]

I went through all this 3 years ago, Actually I never thought about adding or paralleling resistance to the NTCs, I was just happy to have the A/C back. Anyways, I am not going to do anything now as I will sell the car in the next couple of months, It is too big for parking here in view of local changes that have been made.

Thanks for the suggestions which I would have tried when I had the A/C problem.

M

[NumeatonGraham]

Update on my A/C.

It turned out that i had a leaking condenser and a faulty compressor.

These were replaced.

My code reader message said that i had an ecm failure which led me to believe the dcc valve had failed.

After the above components were replaced and the codes reset no more codes were highlighted.

Graham

[gordj65]

On 6/2/2023 at 7:21 PM, NumeatonGraham said:

Hi Gordon,

did you get this sorted.

I get B1263 the same as you when i plug in my scanner.I reset the code.

My aircon has just started to give warm air only and it goes into the garage on Tuesday as we suspect the DCCV,has failed.I decided to checkout the DCCV first as these are known to be unreliable,then checking the

wiring to it as these can get brittle.If no joy i will check the ccm module and send it away for the upgrade.

I believe this route to be the most economical financially initially.I have tried to get the Bosch DCCV but without success so i will put a cheaper one in and look to change asap.

Graham

My apologies for not answering your question. I decided to just leave it at the time and of course now that its getting warmer I am regretting that decision lol. I will update on this if I get it done this year. Using the car a lot less at the moment so I can do most journeys with an open window.