1994 JAGUAR XJ6 display

Climate Control Systems
CL /MATE CONTROL SYSTEM 0 14*2 14.2.1 Description
The climate control system in the 1995 model year saloon has a centre mounted heater / cooler unit with separate
blower assemblies, one LH and one RH. Heating temperature control is effected by means of a coolant flow valve and
circulation pump.
For models fitted with air conditioning, cooling is provide by passing air through the evaporator, which is situated im
- mediately behind the heater / cooler case inlet ducts.
Electric motors with integral potentiometers are used to position
all flaps.
W: There are no vacuum operated components in the system.
14.2.2 Features
o Self diagnostic control system with error codes.
0 Actuator 'self check'.
0 Display element check.
m: These features will be helpful for initial trouble shooting and where Jaguar Diagnostic Equipment (JDE) is not
available.
0 'Soft touch' logic controls. 0
0 Serial link from panel to control module (NCCM).
0 LCD display for temperature, status and fan speed.
0 Variable fan speed, whether in automatic or manual mode.
0 Manual air flow distribution over-rides.
0 Compensated air flow with regard to vehicle speed.
0 Rear footwell outlets.
0 Rear face outlets.
0 Scavenge system closed circuit temperature control.
0 Heated front screen (where fitted).
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Climate Control Systems
14.3 CLIMATECONTROL PANEL
12 13 14 15 16
Fig. 1 Control layout (see key listing below)
The following description of the various control panel functions is provided as a brief over
-view to assist in function
checking. Further information concerning the control panel to component interface may be found in the fault finding
procedures (this section) or the Electronic Diagnostic Manual (EDM).
Iynfe: The system may be activated by any one of four commands. a) AUTO button item 1 1; b) DEFROST button item 12; c) NC button item 10; d) OFF switch item 1.
1. Combined push for OFF and rotary FAN SPEED control. The speed of the two fans is changed by clockwise (to
increase) or anti-clockwise rotation of the knob. Operation of the control, (push) OFF or (rotate) FAN over-rides
the AUTO selection and cancels the 'AUTO' display.
2. RECIRCULATE AIR push-on / push-off button and state lamp, used to prevent outside air being drawn into the
cabin. There are two modes:
a) Press and immediate release; provides timed recirculation of five
(5) minutes. b) Press and hold for two (2) seconds; 'latches' the mode until operator over-ride.
3. Temperature scale SELECTOR for Celsius or Fahrenheit.
4. FANS SPEED display bar graph.
5. TEMPERATURE numeric display for demand and exterior.
6. Selected temperature SCALE temperature numeric display.
7. EXTERIOR temperature option display.
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Climate Control Systems
8. AUTO selection display.
9. EXTERIOR temperature selection button. There are two modes:
a) Press and immediate release; provides timed display of four (4) seconds.
b) Press and hold for two (2) seconds; 'latches' the mode until operator over-ride.
10. A/C push-on / push-off button will either engage or disengage (as indicated by the state lamp) the refrigeration
system compressor. The state lamp is also used as a compressor speed fault indicator,see System protection, this
section.
11. AUTO push-on button and state lamp. When selected and the state lamp lit, the A/C mode is selected and control
of demand temperature, fans speed, and air distribution is automatic. AUTO is cancelled by selection of any 'dis- tribution' button, A/C off, or manual FANS SPEED.
12. DEFROST push
-on / push-off button and state lamp. When engaged, air is distributed to the screen at maximum
fans speed and the heated front screen elements (where fitted) are ener ized. The heated front screen is automati- cally timed for a six (6) minute cycle but may be cancelled by pressing tfe HEATED FRONT SCREEN button. Auto- matic temperature control is retained and the fans speed may be manually reduced. Deselection will return the
system to the previous state and selection of AUTO will resume automatic system control.
13. The push
-on / push-off (F) button with state lamp manually controls the HEATED FRONT SCREEN (where fitted).
This facility allows rapid screen de-icing using laminated electrical heating elements to supplement the hot air
defrost.
14. The push-on / push-off (R) button with state lamp manually controls the HEATED REAR SCREEN and door mirror
glass heating elements for a timed cycle of; screen twenty (20) minutes and mirrors eleven (1 1) minutes.
m: The state lamp will remain lit after the mirror timer has gone through its 11 minute cycle and will not go out
until either completion of the 20 minute screen cycle or manual override.
15. TEMPERATURE decrease button
in IoC or I0F steps.
16. TEMPERATURE increase button in
IoC or I0F steps.
w: Automatic temperature control operates over the range 17OC to 31OC (61OF to 90OF). Extreme limits selected
by items 15 and 16 ('Lo' and 'Hi') provide maximum cooling or heating at maximum fans speed.
17. FACE level manual distribution over
-ride push-on / push-off button and state lamp.
0 18. Bi LEVEL (foot and face) manual distribution over-ride push-on / push-off button and state lamp.
19. FOOT level manual distribution over
-ride push-on / push-off button and state lamp.
20. DEMIST (screen and foot) level manual distribution over
-ride push-on / push-off button and state lamp.
!Y&Q: Selection of AUTO will over-ride any manual setting and deselection of any manual distribution will revertthe
system to AUTO distribution.
21. FACE VENTTEMPERATURE CONTROL thumb
-wheel. Situated between dash centre face level vents to reduce face
air outlet temperature relative to that of the foot-well.
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Climate Control Systems
. Centre vent flap
Foot flap
Defrost flap
I I
14.5.2 Control Module Interfaces
. Recirculation switch
. Air con onloff switch
. System onloff switch
. Auto. / Man. select
. Set temperature
. Air flow outlet mode set
. Heated front screen switch
. Heated rear screen &
. External temp. display
. FahrenheiVCentigrade
heated mirror switch
switch
switches
. Solar sensor
. Motorized in-car aspirator
. Ambient temp. sensor
9 Evaporator temp. sensor
. Heater matrix temp. sensor
. Compressor lock sensor
. Face differential temp. control
. Refrigerant pressure switch
. Engine speed signal
. Engine coolant temperature
Vehicle speed signal
Circulation pump
. Coolant flow valve
. Power transistor (fan speed
= Servo motor potentiometers:
signal
control)
LH air inlet flap
RH air inlet flap
Centre vent flap
Foot flap
Defrost flap
Air by
-pass flap
CONTROL PANEL
4
-
4
4
4
4
4
4
A 1 CCM
e I . External temp. display
. Coolant recirculation valve
. Coolant recirculation pump
Cool air by-pass
Air Flow Speed Control
. LH blower motor & power transistor
. RH blower motor & power transistor
. LH high speed relay
. RH high speed relay
. LH air inlet
. RH air inlet
. Compressor
- . Front screen heater (to EMS)
- . Heated rear screen
and door mirrors
Fig.
1 Schematic view AI CCM Inputs & Outputs
0
0
0
0
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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. The self test sequence has two
basic modes:
0 System error information is stored in the A/CCM up to a maximum of five faults. Should a fault occur there will
be an audible 'beep' and the message 'Er' will be displayed on the control panel LCD for approximately five (5)
seconds after ignition on. Please note that this will happen only once in any ignition switch cycle. The error
source may be accessed by the procedure described in 'Self Test System Diagnosis', this section.
0 Panel communication check may be initiated by following the instruction in 'Self Test System Diagnosis', this
section.
Nsfe: Displayed error codes are NOT directly related to Jaguar Diagnostic Equipment (JDE) but more detailed fault
related information may be accessed using Portable Diagnostic Unit (PDU).
14.6.2 System Protection
Power to the compressor clutch may be cut should either the engine management or air conditioning control systems
detect certain conditions; these conditions may be caused by Fault or Demand and can be classified thus:
0 Engine coolant overheat,
0 Refrigerant excessive pressure.
0 Refrigerant, insufficient pressure or low charge weight.
0 Speed differential between compressor and crankshaft caused by belt slippage or compressor seizure (indi-
cated by A/C state lamp flashing once per second) - 12 cylinder engine only. This feature, 'lock sensing' is fully
explained
in the EDM.
Demand
0 Engine maximum power requirement
0 Electrical system drain at engine idle.
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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.
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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.*
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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
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