1994 JAGUAR XJ6 climate control system

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Page 322 of 521

JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
CONTROL MODULE FAULT & CONDITION SELF-ANALYSIS
0 14.6 14.6.1 System Health
The climate control system has a self-test facility, accessible from the control panel.

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
14.7 AIR DlSTRlBUTlON
(Refer to illustrations on this and next page)
Air is drawn from the plenum chamber into the heater/cooler case at the lower front right and left

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$JAGUAR XJ6 1994 2.G Workshop Manual 0 0 0 Climate Control Systems &j% \d J82-697 Fig. 1 k9 J82-498 X300 VSM 11 Issue 1 August 1994$

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
14.8 REFRIGERATION CYCLE:
The Compressor draws low pressure, low temperature re- frigerant from the evaporator and by compression, raises re- frigerant temperature and

Climate Control Systems
14.8 REFRIGERATION CYCLE:
The Compressor draws low pressure, low temperature re- frigerant from the evaporator and by compression, raises re- frigerant temperature and pressure. High pressure, hot
vaporized refrigerant enters the Condenser where it is
cooled by the flow of ambient air.
A change of state occurs
as the refrigerant cools in the condenser and it becomes a
reduced temperature high pressure liquid.
From the condenser the
liquid passes into the Receiver / Drier which has three functions,
a) Storage vessel for varying system refrigerant demand.
b) Filter to remove system contaminants. c) Moisture removal via the dessicant.
With the passage through the
receiver/drier completed the,
still high pressure liquid refrigerant enters the Expansion
Valve where it is metered through a controlled orifice which
has the effect of reducing the pressure and temperature.
The refrigerant, now
in a cold atomized state, flows into the
evaporator and cools the air which is passing through the
matrix.
As heat is absorbed by the refrigerant
it once again changes
state, into a vapour, and returns to the compressor for the
cycle to be repeated (Fig.
1).
There is an automatic safety valve incorporated in the com- pressor which will operate should the system pressure be in
excess of 41 bar. The valve will reseat when the pressure
drops below 27,6 bar.
W Thedivisionof HIGHandLOWsideissimplythesys- tem pressure differential created by the compressor
discharge (pressure), suction (inlet) ports and the
relative inlet and outlet ports
ofthe expansion valve.
This differential is critical to system fault diagnosis
and efficiency checks.
Twelve Cylinder Vehicles only:
Dual pressure switch: This two-function pressure switch
cuts electrical power to the compressor clutch if the system
pressure is outside of the range
of 2 Bar (1st Function) to 30
Bar (2nd Function).
Six Cylinder Vehicles only:
There are two switches incorporated into the high side of the
system which have the following functions:
a) Trinary; This three function pressure switch, cuts electri
-
cal power to the compressor clutch should the system pres- sure not be in a range of 2 bar (1st function) to 30 bar (2nd
function). The switch also provides a ground signal to oper
- ate the appropriate relay (within the 'Stribel,' unit) to ener- gize both engine cooling fans when maximum A/ C cooling
is required. Operation pressure, 20 bar input (3rd function).
b) Pressure Switch Slow Cooling Fans; When the system
pressure is 12 bar, medium A/ C demand, the operation of
this switch connects both engine cooling fans in series to op- erate at half battery voltage and so, half fan speed. 1.
Compressor
2. Condenser
3. Receiver / Drier 4. Expansion Valve
5. Evaporator
6. Pressure switch - Dual type
on 12
cyl & Trinary on 6 cyl
Fig. 1
0
0
Issue 1 August 1994 12 X300 VSM

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
0 14.9 GENERAL SYSTEM PROCEDURES
14.9.1 Leak Test
Faults associated with low refrigerant charge weight and low pressure may be caused by leakage. Leaks traced to
me

Climate Control Systems
0 14.9 GENERAL SYSTEM PROCEDURES
14.9.1 Leak Test
Faults associated with low refrigerant charge weight and low pressure may be caused by leakage. Leaks traced to
mechanical connections may be caused by torque relaxation or joint face contamination. Evidence of oil around such
areas is an indicator of leakage. When checking for non visible leaks use only
a dedicated HFC 134A electronic analyzer
and apply the probe all round the joint / connection.
Should a leak betraced to a joint,checkthatthefixing issecuredtothecorrecttightening torque before any other action
is taken.
Do not forget to check the compressor shaft seal and evaporator.
CAUTION : Never use a dedicated CFC 12 or naked flame type analyzer.
14.9.2 Charge Recovery (System depressurization)
The process of HFC 134A recovery will depend on the basic characteristics of your chosen recovery/ recycle I recharge
equipment, therefore, follow the manufacturer's instructions carefully.
Remember that compressor oil may be drawn
out of the system by this process, take note of the quantity recovered
so that it may be replaced.
CAUTION: Observe all relevant safety requirements.
Wear suitable eye and skin protection
Do not mix HFC 134A with CFC 12. Do not vent refrigerant directly to atmosphere and always use Jaguar approved recovery I recycle I re- charge equipment.
Take note of the amount of recovered refrigerant, it will indicate the state of the system. 0
14.9.3 Evacuating the System
This process, the removal of unwanted air and moisture, is critical to the correct operation of the air conditioning sys-
tem. The specific procedures will vary depending on the individual characteristics of your chosen recovery I recycle / recharge equipment and must be carried out exactly in accordance with the manufacturers instructions. However,
it is recommended that the initially only the HIGH side valve be opened at the start of the procedure. After a short time a small depression should be seen on the LOW side, at which point the LOW side valve may be opened and the evacu- ation process completed. If a vacuum is not registered on the LOW side it may indicate that the expansion valve is
jammed closed or that the system is blocked. This simple check may save time and effort when the system is re- charged.
Moisture can be highly destructive and may cause internal blockages due to freezing, but more importantly, water sus- pended in the PAG oil will damage the compressor. Once the system has been opened for repairs, or the refrigerant
charge recovered, all traces of moisture MUST be removed before recharging.
14.9.4
The amount of oil drawn out during a recovery procedure will be dependent on the state of the system and the rate
of recovery. The quantity will be approximately 30 to 40 ml; this may vary, and the figure is given only for guidance.
The oil separator vessel in the recovery equipment must be clean and empty
at the start of the process so that the quan- tity of oil which is drawn out may be accurately measured.
Oil may be added by three methods,
1 and 2 being direct into the system and 3 with the compressor off the vehicle;
1. Via the recovery I recycle 1 recharge station.
2. Proprietary oil injector.
Adding Lubricating Oil - Compressor Related
1ynfa: Equipment manufacturer's instructions must be adhered to when using direct oil introduction.
3. Directly into the original, or new unit, because of rectification work to the existing compressor, or the need to fit a new compressor.
Original
From an existing compressor, drain the oil into a measuring cylinder and record the amount. Flush the unit out
with fresh PAG oil and drain thoroughly, Replenish the compressor with the same amount of PAG oil that was
originally drained out and immediately plug all orifices ready for refitting to the vehicle.
X300 VSM 13 Issue 1 August 1994

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
New
Drain and discard the transit lubricating oil from a new compressor before it is be fitted. An adjustment must
then be made to avoid over-filling the system,

Climate Control Systems
New
Drain and discard the transit lubricating oil from a new compressor before it is be fitted. An adjustment must
then be made to avoid over-filling the system, by taking into account;
a) the quantity found in the original compressor.
b) the quantity deposited in the recovery equipment oil separator from the charge recovery operation.
Drained from original compressor
50 ml
Recovered from oil separator 40 ml
Quantity to be put in new compressor 50 + 40 = 90 ml
Typical example:
Please note that the discrepancy between the cumulative figure of recovered and drained oil and the nominal capacity
of
180 ml is caused by normally unrecoverable oil being trapped in components such as the condenser, receiver/ drier
or evaporator.
The previous statements apply even
if a problem has occurred due to oil leakage. The amount of oil lost due to leakage
is generally small, so to avoid over-filling please follow the example.
If however the recovery process has not been necessary because refrigerant has also been lost, then ONLY replace the
quantity drained from the original compressor.
14.9.5
Should a major component such as condenser, receiver / drier or evaporator be renewed then an adjustment to the
system oil level must be made. This may be carried out in the same way as the examples for the compressor except
for the fact that trapped oil within any one of these components cannot normally be drained. Therefore, a nominal
amount of oil should be substituted
in addition to that recovered from the recovery station separator.
Adding Lubricating Oil - Component Related
Condenser Add 40 ml
Evaporator Add 40 ml
Receiver / drier NO adjustment
CAUTION: Always decant fresh oil from a sealed container and do not leave oil exposed to the atmosphere. PAG
oil is very hygroscopic (absoh water) and will rapidly attract atmospheric moisture.
PAG oil must NEVER be mixed with mineral based oils.
Do not re-use oil following a recovery cycle, dispose of it safely.
14.9.6 Adding Refrigerant
In order that the air conditioning system may operate efficiently it must contain a full refrigerant charge. The indica- tions of some system defects, and the results of certain tests, will show that a low charge is the most probable cause
of the fault. In such cases the charge should be recovered from the system, the weight noted, and the correct amount
installed.
Should refrigerant be added in liquid form, initial engine start
-up revolutions must NOT exceed 2000 RPM for a period
of (2) two minutes. If the engine speed is excessive, compressor damage may occur due to the lubricating oil and the
liquid refrigerant being initiallyforced around the system as a 'slug', thus taking oil awayfrom the compressor. These
marginal lubrication conditions in the compressor will cease as the refrigerant becomes gaseous.
Never attempt to 'guess' the amount of refrigerant in a system, always recover and recharge with the correct charge
weight; this is the only accurate method.
CAUTION: If oil was drawn out during the recovery process, the corM amount may be added directly from your
recovery / recycle /recharge station (if so equipped) prior to the 'charging process'. It must be stressed that the need to protect compressor oil from moisture is vital, observe the procedures
in HANDLING LUBRICATING OIL and those concerning excessive engine revolutions.
Issue 1 August 1994 14 X300 VSM

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
14.10 FAULT DIAGNOSIS
14.10.1 Introduction
It is very important to positively identifythe area of concern before starting a rectification procedure. A little time sp

Climate Control Systems
14.10 FAULT DIAGNOSIS
14.10.1 Introduction
It is very important to positively identifythe area of concern before starting a rectification procedure. A little time spent
with your customer to identify the conditions under which a problem occurs will be beneficial. Relevant criteria are:
Weather conditions, ambient temperature, intermittent or continuous fault, airflow fault, temperature control fault, dis
- tribution fault and air inlet problem.
14.10.2 Functional Check
This simple 'first line check' will allow you to ascertain whether the system is operating within its design parameters,
without recourse to (JDE). Please carry out the following, in order.
0 Start engine and attain normal running temperature.
0 Presss AUTO to display selected temperature and illuminate AUTO & AJC state lamps.
0 Rotate FAN to increase or decrease lower speed, verify bar graph representation.
0 Operate AJC to toggle on or off. Because the compressor can be inhibited by the engine management system,
ensure that the engine temperature is normal and that the ambient is above 5O C.
0 Operate RECIRC, state lamp should be lit and the flap behind the blower grille open.
0 Operate distribution buttons in turn, verify correct air distribution and relevant state lamp.
0 Operate DEFROST, check max fans and air to front screen.
0 Cycle TEMPERATURE to 'Hi' and 'Lo' to verify demanded variations and display operation. Note that extremes
will provide max heat or cold independent of in-car temperature.
0 Operate EX to toggle between ambient and control temperatures.
0 Operate HFS and HRW to note timer and mirror operation.
0 Initiate System Self Test to check for, and extract, stored faults should any of the above not perform as stated.
14.10.3 System symptoms
There are five basic symptoms associated with air conditioning fault diagnosis. The following conditions are not in order of priority.
No Cooling
0 Is the electrical circuit to the compressor clutch functional?
0 Is the electrical circuit to the blower motor(s) functional?
0 Slack or broken compressor drive belt.
0 Compressor partially or completely seized.
0 Compressor shaft seal leak.
0 Compressor valve or piston damage (may be indicated by small variation between HIGH &LOW side pressures
relative to engine speed).
0 Broken refrigerant pipe (causing total loss of refrigerant).
0 Leak in system (causing total loss of refrigerant) - possible code 23.
0 Blocked filter in the receiver drier.
0 Evaporator sensor disconnected - possible code 13.
0 Pressure switch faulty - possible code 23.
X300 VSM Issue 1 August 1994

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JAGUAR XJ6 1994 2.G Workshop Manual Climate Control Systems
lnsufficent Cooling
0 Sluggish blower motor(s).
0 Restricted blower inlet or outlet passage
0 Blocked or partially restricted condenser matrix or fins.
0 Blocked or p

Climate Control Systems
lnsufficent Cooling
0 Sluggish blower motor(s).
0 Restricted blower inlet or outlet passage
0 Blocked or partially restricted condenser matrix or fins.
0 Blocked or partially restricted evaporator matrix.
0 Blocked or partially restricted filter in the receiver drier.
0 Blocked or partially restricted expansion valve.
0 Partially collapsed flexible pipe.
0 Expansion valve temperature sensor faulty (this sensor is integral with valve and is not serviceable).
0 Excessive moisture in the system.
0 Air in the system.
0 Low refrigerant charge - possible code 23.
0 Compressor clutch slipping.
0 Blower flaps or distribution vents closed or partially seized - possible codes 41 or 46.
0 Coolant flow valve not closed.
0 Evaporator sensor incorrectly positioned
m: Should a leakor low refrigerant be established as the cause of /NSUff/C/€NTCOOL/NG,followthe procedures
Recovery / Recycle / Recharge, this section, and observe all refrigerant and oil handling instructions.
lntermiffent Cooling
0 Is the electrical circuit to the compressor clutch consistent?
0 Is the electrical circuit to the blower motor(s) consistent?
0 Compressor clutch slipping?
0 Motorized in-car aspirator or evaporator temperature sensor faulty, causing temperature variations - possible
codes 11 or 13.
0 Blocked or partially restricted evaporator or condenser.
Noisy System
0 Loose or damaged compressor drive belt.
0 Loose or damaged compressor mountings.
0 Compressor oil level low, look for evidence of leakage.
0 Compressor damage caused by low oil level or internal debris.
0 Blower motor(s) noisy.
0 Excessive refrigerant charge, witnessed by vibration and 'thumping' in the high pressure line (may be indicated
by high HIGH & high LOW side pressures).
0 Low refrigerant charge causing 'hissing' at the expansion valve (may be indicated by low HIGH side pressure).
0 Excessive moisture in the system causing expansion valve noise.
0 Air-lock in water pump*.
lnsufficent Heating
0 Coolant flow valve stuck in the closed position.
0 Motorized in-car aspirator seized.
0 Cool air by-pass damper stuck or seized - possible code 43.
0 Blocked or restricted blower inlet or outlet.
0 Low coolant level.
0 Blower fan speed low.
0 Coolant thermostat faulty or seized open.
0 Water pump inoperative or blocked
0 Air-lock in matrix*.
m: * Please see Sections 4.1 and 4.2 for specific coolant fill / bleed procedures.
Electrical faults may be more rapidly traced using
(JDE), please refer to the (EDM).
Issue 1 August 1994 16 X300 VSM

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