1994 JAGUAR XJ6 check engine

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

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

Climate Control Systems
Action
Simultaneously hold AUTO and RECIRC - Switch
ignition to ON
Press AUTO
Press FACE
Simultaneously press FACE and HRW
Press
RECIRC (Press FAN to skip actuator check)
Press FAN
14.11 SYSTEM SE1 F-TEST
14.11. I Interrogation Procedure via the Control Panel
Result
Display element check
Any stored fault NUMERIC code
(If ZERO appears there are
no stored codes)
Scroll through stored faults (maximum of
5)
Clear stored fault codes (may need to be repeated for each
fault)
Initiate actuator check (Actuator codes
20 through 27*)
Exit error check mode
Fault Code
0
11
12
13
14
15
21
22
0
23
14.1 1.2 Control Panel Fault Code Key
Item Description
Normal Operation No
fault codes present, wait 30 seconds for system self-
check.
Motorized In
-car Aspirator Open /short in sensor circuit. Panel fault codes are not stored
for motorized in
-car aspirator motor failure.
Ambient Temperature Sensor Open
/ short circuits.
Evaporator Temperature Sensor Open
/ short circuits.
Water Temperature Input Instrument pack output.
Heater Matrix Temperature Sensor Open
/ short circuits.
Solar Sensor Open
/ short circuits.
Compressor Lock Signal
- 12 cylin- Open /short circuits. Low gas charge, low compressor oil,
der and supercharged
6 cylinder loose belt.
engines only.
Refrigerant Pressure Switch Open /short circuits. Low gas charge*
31
32
33
34
35
36 0
I 24 1 Face Vent Demand Potentiometer. 1 Open / short circuits
LH Fresh
/ Recirc. Potentiometer
RH Fresh / Recirc. Potentiometer
cool ~i~ by-pass potentiometer
Defrost Vent Potentiometer
Centre Vent Potentiometer
Foot Vent Potentiometer Open
/short circuit
in potentiometer. feed.
w: and log further faults. Cycling the ignition two or three times
after rectification of the fault will cure this.
In certain circumstances, the motor can over-travel
43
44
I Defrost Vent Motor
I Cool Air by-pass Motor
I 41 I LH Fresh / Recirc. Motor I
Check for short / open circuits in motor drive lines. Motor flap
sticking
/ jammed.
1 42 I RH Fresh / Recirc. Motor I
1 45 I Centre Vent Motor I
46 I Foot Vent Motor
w: In ambient temperatures below Oo C, the system may log fault code 23 because the low ambient causes a tem-
porary low gas pressure. Where the ambient temperature rise above 40" C, and if the engine is close to over- heating, feed to the compressor clutch may be cut and code 23 registered.*
X300 VSM 17 Issue 1 August 1994

Climate Control Systems
No heat
One vent failing to open
/ close
Poor airflow
14.11.3 Associated Faults
Other symptoms that may exist without storing fault codes:
Airlock in system.
Electric water
pump inoperative
Coolant flow valve stuck closed
Faulty engine coolant thermostat
Broken linkage.
Blower motors
- incorrect operation
14.11.4 Panel Communication Check
Action Result
Panel communication
with FACE, FOOT & FACE, FOOT,
SCREEN
& FOOT, DEFROST, RECIRC lines checked - State lamps will illuminate if all is OK. Unlit state lamp
means continuity fault for that specific link. See EDM
for
full check.
0
0
0
Issue 1 August 1994 18 X300 VSM

Climate Control Systems
14.13 SYSTEM CHECKING WITH MANIFOLD GAUGE Sm
14.13.1 Evacuating the Manifold Gauge Set
Attach the centre (service) hose to a vacuum pump and start the pump. Open fully both high anddow valves and allow
the vacuum to remove air and moisture from the manifold set for at least five minutes.
Turn the vacuum pump off and isolate it from the centre service hose but do not open the hose to atmosphere.
CAUTION: It is imperative that the vacuum pump is not subjected to a positive pressure of any degree. Therefore
the pump must be frtted with an isolation valve at the centre (service hose) connection and this valve
must be closed before the pump is switched off. This operation replaces the 'purge' procedure used on
previous systems. Observe the manufacturefs recommendation with regard to vacuum pump oil
changes.
14.13.2 Connecting the Manifold Gauge Set
CAUTION: Only use hoses with connectors which are dedicated to HFC 134A charge ports.
Attachment of the hose quick release connectors to the high and low side system ports is straightfotward, provided
that the high and low valves are closed and the system is NOT operational.
Assessment of system operating efficiency and fault classification may be achieved by using the facilities on your
Re- covery / Recharging / Recycling station, follow the manufacturers instructions implicitly and observe all safety con- siderations.
WARNING: UNDER NO CIRCUMSTANCES SHOULD THE CONNECTIONS BE MADE WITH THE SYSTEM IN
OPERATION OR THE VALVES OPEN. SHOULD THE VALVES BE OPEN AND A VACUUM PUMP OR
REFRIGERANT CONTAINER ATTACHED, AN EXPLOSION COULD OCCUR AS A RESULT OF HIGH
PRESSURE REFRIGERANT BEING FORCED BACK INTO THE VACUUM PUMP
OR CONTAINER.
14.13.3 Stabilizing the System
Accurate test gauge data will only be attained if the system temperatures and pressures are stabilized.
Ensure that equipment and hoses cannot come into contact with engine moving parts or sources of heat.
It is recommended that a free standing air mover is placed in front of the vehicle to provide air flow through the con- denser / cooling system, see illustration below.
Start the engine, allow
it to attain normal working temperature and set at fast idle (typically 1200 to 1500 rpm). Select full air conditioning performance.
With all temperatures and pressures stable, or displaying symptoms of faults; begin relevant test procedures.
Fig.
1
Issue 1 August 1994 20 X300 VSM

Climate Control Systems
High Side Gauge
Normal
@ 14.16 SYSTEM PRESSURE FAULT CLASSIFICATION
This table should be used in conjunction with the graphical representations of 'High side' pressure / ambient tempera- ture and 'Low side' pressure / evaporator temperature, this section.
Fault Cause
Discharge air initially cool then Moisture in system
warms up
1 Low Normal
Low
Low
Low
Low
I Low
As above As above
Discharge air slightly cool HFC
134A charge
low
Discharge air warm HFC
134A charge very low
Discharge air slightly cool or frost Expansion valve
stuck closed
build up
at expansion valve
Discharge air slightly cool, sweat
- Restriction in High side of
ing or frost
after point of restriction system
I
Low
High
High
I
Compressor noisy Defective compressor
reed valve
Discharge air warm and high side HFC
134A charge
high or
pipes hot inefficient
condenser cooling
dueto
air flow blockage or engine cooling
fans not working
Expansion valve stuck open
Discharge air warm
Sweating or frost
at evaporator
If erratic or unusual gauge movements occur, check the equipment against a known (calibrated) manifold
gauge
set. ~ ~~~
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rl Electrical
15.1.6 Fire Hazard Infonnath
Thermal decomposition or combustion may produce dense smoke and other dangerous fumes which in fire situations
form
a highly toxic explosive.
In the event of fire the surrounding area must be evacuated and
all personnel kept well upwind of the area.
Full fire fighting protective gear and
a self contained breathing apparatus operating in the positive pressure mode must
be worn for combating fire. Material near fires must be cooled with water spray to prevent ignition.
Fires should be allowed to burn themselves
out if not threatening to life or property. If fire is threatening to life or prop- erty use copious quantities of water to extinguish.
15.1.7 Ventilath
Local exhaust ventilation designed by a professional engineer should be provided if vapours, fumes, or dusts are gen- erated whilst working with airbag module.
The latest issue of the manual for recommended practices on 'Industrial Ventilation' is available from the
ACGIH Com- mittee on Industrial Ventilation, PO Box 16153, Lansing, MI 48910, USA.
The need for local exhaust ventilation should be evaluated by a professional industrial hygienist.
15.1.8 Respiratory Precauth
To prevent the inhalation of dangerous fumes and dusts, an approved mask should be worn.
15.1.9 Eye Protection
Chemical protective goggles are recommended where there is a possibility of eye contact with the propellant.
Safety glasses with side shields are recommended for
all other operations.
15.1. I0 Protective Clothing
Approved protective gloves, overalls and shoes / boots should be worn.
15.1.1 1 Handling and Storage Precautions
Do not store airbag module near live electrical equipment or circuitry. Store in a dry environment at ambient tempera-
tures.
Good housekeeping and engineering practices should be employed to prevent the generation and accumulation of
dusts. Store in compliance with
all local state and federal regulations.
15.1.12 Driver And Passenger Airbag Modules Assembly / Removal / Service Instructions
Before starting work, ensure ignition switch is in 'IocK position, key is removed and negative terminal cable
is disconnected from the battery.
As the airbag is equipped with a back up power source and due to the risk of airbag being inadvertently
deployed, wait one minute or longer before starting work.
0 Disconnecting the battery cancels the memory for clock, radio, seats, mirrors, steering column and any other
components using battery power. Reset memory after work is completed.
0 Never use airbags from other vehicles, always use new parts.
0 After work is completed, reconnect battery and perform warning light check see diagnostic manual.
0 Never use electrical probes to check voltage or electrical resistance.
0 Disconnect the airbag before carrying out any work on, or in the vicinity of module, or when using electric weld- ing equipment.
0 Always ensure that battery negative has been disconnected for one minute or longer before commencing any
removal procedure.
EB
Issue 1 August 1994 4 X300 VSM

31
30
29
28 27
26
4 26 24 21 23 22 7 20 19 18 18 17 8
a
10
11
12
13
14
1s
1M-137
1. Tachometer 2. Speedometer
3. Battery Condition 4. FuelGauge 5. Oil Pressure 6. Coolant Temperature 7. Odometer /Trip Computer Display 8. Primary Warning Indicators (RED) 9. Exhaust Temperature 10. Low Oil Pressure 11. Seat Belt Not Fastened 12. Boot Open 13. DoorOpen 14. Coolant Level 15. Air Bag Fault 16. Status / Warning Lamps
17. Hand Brake On (RED) 18. Brake System Fault (RED)
19. Main Beam On (BLUE) 20. Direction Indicator Right (GREEN) 21. Status / Warning Lamps 22. Direction Indicator Left (GREEN) 23. Traction Control Off (GREEN) 24. Transmission Sport Mode (GREEN) 25. Charging Fault (RED) 26. Check Engine (AMBER)
27. Low Fuel Level (AMBER) 28. Anti - Lock Fault (AMBER) 29. Traction Control Fail (AMBER) 30. Bulb Fail (AMBER) 31. Washer Fluid Level (AMBER) 32. Transmission Fault (AMBER)
Fig.
1 Instrument Panel, Front Mew
w: The 'Premium Unleaded Fuel Only' caution is added to the Federal Market vehicles, also 'PARK BRAKE and
'BRAKE' replace international symbols used in all other markets.
m: Six cylinder vehicle version shown; the tachometer red-line on 12 cylinder vehicles starts at 6000 RPM.
The front of the
PECUSprogrammable instrument panel features 6 analog gauges, 22 warning lamps /tell tales and
a Liquid Crystal Display (LCD), the rear of the panel accommodates two PCB mounted connectors, one 24-way
connector, one 48-way connector, one instrument panel identification label and 14 light bulbs arranged in groups of
seven on either side. Three power inputs and two ground inputs are provided for 'POWER UP' and 'POWER DOWN'
sequence, the three power inputs comprising battery, ignition and auxiliary. The instruments are protected by a
housing
/ lens assembly.
15.2.7 Gauges
The two major gauges are tachometer and speedometer, and the four minor gauges indicate battery condition, fuel
level, oil pressure and coolant temperature.
Each gauge is contained
in a sealed non-serviceable can and must be renewed as a complete unit in case of any
damage.
CAUTION: Extreme care should be exercised when renewing instrument pand components to avoid damago to the delicate indicator needles.
X300 VSM 9 Issue 1 August 1994