Had the system gassed recently and it held the vacuum test for 20 minutes brilliantly. The car is not used much and after a couple of weeks the aircon stopped working. If I press the little valves in the sevice ports there is a hissing sound, still pressure in the system but do not know how much.
Which OBD scanner tool allows me to get into the aircon ecu to find if there are faults detected?

Thanks, Olav

 

The A/CCM can store DTCs and the panel can display many of them.
Jaguar Publication SERVICE TRAINING COURSE 701 has a list of Panel DTC descriptions.

Denso Climate Control System
Control Panel Diagnostics
System Self-Test
Some system generated fault codes can be displayed on the control panel screen. When a fault is
flagged, an audible “beep” will sound and the message “Er” will be displayed for five seconds, after
the ignition is switched to position II. To display stored “panel fault codes”, follow this procedure:
• Switch off the ignition
Press and hold the AUTO and FRESH / RECIRC buttons simultaneously while switching the
ignition to position II.
All of the panel LEDs and all LCD segments will flash ON and OFF. Any function LED indicator
or LCD segment that does not flash suggests a fault condition within that area of the panel,
or with the LED or LCD.
• Press AUTO
The control panel display will flash and scroll through the list of flagged fault codes. A maximum
of five codes will be stored and displayed. If 0 is displayed, no fault codes are flagged.
• Press FACE to manually scroll through the fault codes
When a fault code is displayed, an accompanying beep will indicate if the fault is present.
If the code is not accompanied by a beep, the fault occurred previously.
NOTE: Faults that are present can not be cleared until the cause of the fault is repaired.
To clear fault codes, press HRW and FACE simultaneously. Wait 30 seconds for the A/CCM
to retest the system and reflag any current faults.
• Press PUSH OFF to return the system to normal operation (default panel settings)

The DTC info on pages 61 to 64

 

Thank you so much for that. This is very helpful.

 

That is a very comprehensive guide that I had not seen. Thanks, Bob.

Here is the page from the service manual summarizing the panel checks. Code 23 probably means you have lost your refrigerant again, even if there still appears to be some in it. This would prevent the compressor from turning on.

I don't think you'll find a scan tool that can read the body B codes for the air con. Only the old dealer level equipment can. Hard to find unless you live near Wise County, Texas.

In my experience the air con valves are the most likely cause of refrigerant loss. Be sure to replace them before you get another recharge. They are standard GM style ball valves. Also the condenser can wear out along the bottom edge due to evaporated rubber lower bushings, rust or damage.

 

Hello Richard,
thanks for that. Will be able to work on the Jaguar not untill next weekend. Not sure what you mean by aircon valves. Are these the entry ports for the high and low pressure side? They have black caps on them, threaded. I found uv dye marks on the threads of one of the two.

I’ll update in a couple of days.

 

Thats right, the high and low service ports. The black caps are more for protection and don't really seal the valves. The system could still hold a vacuum while the a/c service equipment is connected, but if the valves are bad the gas will come back out when it is disconnected.

If the system still has some pressure in it, you can spray some soapy water into the valves to watch for bubbles coming out - indicating a leak. Sometimes the valves are so bad you can feel the pressure build up under your finger as you hold it on the valve. UV dye will help find any other leaks too.

 

It has been a while since the last time I took my DD6 for a ride, so today I picked up on the aircon issue again. I bought a UV light to see if there is any leak in the system. I figured that if I could see a clear trail of dye at the condensation tube it could indicate a leaking matrix which I am not going to fix. I was under the car but couldn’t find this condensation tube.
Can anyone give me directions on where tube can be found?

Thanks, Olav

 

The V12 plumbing is different then the inline 6 but shares the same air conditioning system controlled by the same Denso brand ECU

To know your compressor is engaged by the compressor clutch you would feel that the high pressure line is hot to the touch

This is normal operation as the freon is compressed

The line goes into the firewall in the same location as the inline 6 and returns back out a couple of inches from each other

The clutch coil is controlled by the ECU through a large A / C clutch relay that can be swapped with a headlight or fog light relay

The clutch has a single wire connector that is not robust and exposed to the elements




There is a fuse involved # # 8 / 10 amp right engine bay fuse box

and fuse # 10 / 5 amp right engine fuse box

The clutch coil can be replaced leaving the compressor installed along with not opening up the plumbing and the freon charge

The clutch parts are not special Jaguar parts and are common available

Featured Products (shopcenturyautoair.com)

They have the parts to overhaul the compressor yourself if it gets to that and I am assuming you have a Denso compressor


and part 2

There is a mode of failure where the in the cabin temp sensor can get clogged with lent and cleaned not using a solvent that could deprive the sample air fan into the sensor some lubricate

The outside air temp sensor in the left front tire brake cooling duct can get a dirty connector from the environment it is in

If the system is unpressurized there is the suggestion from Motercarman to pressure air flush the thermo expansion valve that is located behind the rear engine firewall from the front of the firewall plumbing connections

The TXV can get clogged from the particles in the freon dryer that let loose as it ages

A test for this is one thing and a repair without digging out the TXV is when you have a empty freon charge is easy

 

That's a good idea Olav. I checked my condensation tubes recently to make sure they were clear. They come off of the lower corners of the matrix housing and are accessible from each footwell without removing anything. The tubes should pull off of the fittings and you can check them with UV. Then put a wire down the tube and up gently into the hole, to be sure they are not clogged. The right tube (on a LHD car) is easier to reach.

The lower end of the tubes come out between the transmission and the exhaust pipes, but are short and not easily visible. A leaky matrix would probably leave a mess of UV dye in those areas.

 

Thank you Parker7 and Richard, this is valuable and useful information. I will go through these step by step.

Olav.

 

The matrix ( heater core as called in the states ) is not used in the A / C system

It does get clogged though

Both the heater matrix and A/ C evaporator are both contained in the same housing on the aft side of the engine firewall

This is referred to as the plenum assembly

Pic coming as I have the heater core marked in red and the evaporator marked in blue

 

Very interesting and informative. My ‘95 has the error and beeping and was diagnosed as having the dryer let loose all of its desiccant that subsequently blocked the TVX. Many of the beads were blown out and the ac seems to work but the error and beeping are still there. I’m interested to hear about how to clear the TVX without “digging it out” since that needs to have the dash disassembled. Cheers.

 

Mptorcarman would blow it out from both directions multiple times

Me not having done it , the lines are are the 2 stubs on the rear engine firewall

These stubs would fit into the holes in the black surround foam square in the above pic

Something that I would ad is that after blowing out the beads as a dry line , later would blow through some PIG oil to possibly free up the valve and there was a change in PIG oil and they do not mix

And let t soak for a couple of days before freon charging and system running

This is a while you are there item

The question becomes if you have a slug of oil returning to the compressor it may harm the compressor as a more solid liquid vs. a compressible gas

This would be a question for a professional in the field of practice