1994 JAGUAR XJ6 differential

Climate Control Systems
SECTION CON TENTS
Subsection Title SRO Page
14.1 ............. System Description ................................................................... 1
14.2 ............. Component Descriptions .............................................................. 3
14.2.1 ............ Control Panel ........................................................................\
3
14.2.2. ........... Control Panel Inputs / Outputs ......................................................... 3
14.2.3. ........... Solar Sensor ........................................................................\
. 4
14.2.4. ........... Engine Speed Signal .................................................................. 4
14.2.5 ............ Ambient Temperaturesensor ........................................................... 4
14.2.6 ............ Vehicle Speed Signal ................................................................. 4
14.2.7.
........... Evaporator Temperature Sensor ......................................................... 4
14.2.8. ........... Heater Matrix Temperature Sensor ...................................................... 5
14.2.9.
........... Coolant Temperature Signal ............................................................ 5
14.2.10
.......... Compressor ONSignal ................................................................ 5
14.2.11 ........... Motorized ln-car Aspirator ............................................................ 5
14.2.12 .......... CompressorLockSignal ............................................................... 5
14.2.13
.......... Refrigerant Pressure Switch ............................................................ 5
14.2.14
.......... Water Valve ........................................................................\
. 5
14.2.15 .......... Water Pump ........................................................................\
. 5
14.2.16
.......... Servo Motor Control .................................................................. 6
14.2.17 .......... Blower Motor Control ................................................................ 6
14.2.18 .......... Differential Control ................................................................... 6
14.2.19
.......... Heated Rear Window, Door Mirrors and Front Screen ...................................... 6
14.3 ............. Climate Control Module Connections ................................................... 7
14.4 ............. Climate Control System Test .......................................................... 10
14.4.1
............ Fault Code Extraction and Deletion Procedure ........................................... 10
14.5
............. Fault Codes ........................................................................\
11
14.6 ............. Actuator Check ..................................................................... 12
14.7
............. Diagnostic Tests .................................................................... 13
14.7.1
............ Fault Code 11 ...................................................................... 13
14.7.2.
........... Fault Code 12 ...................................................................... 14
14.7.3
............ Fault Code 13 ...................................................................... 15
14.7.4.
........... Fault Code 14 ...................................................................... 16
14.7.5
............ Fault Code 15 ...................................................................... 16
14.7.6
............ Fault Code21 ...................................................................... 17
14.7.7 ............ FaultCode22 ...................................................................... 17
14.7.8 ............ Fault Code23 ...................................................................... 18
14.7.9. ........... Fault Code 24 ...................................................................... 18
X300 EDM i Issue 1 August 1994

Climate Control Systems
.-)
14.1 SYSTEM DESCRIPTION
The Air Conditioning electronic Control Module (A/ CCM) located on the right-hand side of the A / C unit, controls the 0 functions of the system.
These functions include:
0 In-car temperature control
0 In-car humidity control (Air conditioning vehicles only)
0 Air flow / volume and distribution
The temperature of the passenger compartment is continuously compared with the temperature selected on the con
- trol panel LCD. A digital microprocessor within the A/ CCM receives the data signals. Comparison of these signals
and those from system temperature sensors and feedback devices results in the appropriate output voltage changes
needed to vary the blend of air flow into the passenger compartment.
The climate control system peripherals communicate with the A/ CCM via three main device categories comprising
of manual inputs, automatic outputs and inputs, as shown
in Fig. 1.
Air Temperature Control I
9 Recirculation switch
. Air con on/off switch
System on/off switch
. Auto. / Man. select
Set temperature
. Air flow outlet mode set
Heated front screen switch
. Heated rear screen &
heated mirror switch
. External temp. display
switch
. FahrenheiVCentigrade switches
4
. Solar sensor
. Motorized in-car aspirator
. Ambient temp. sensor
. 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
. Water 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
Air Inlet Control
9 LH air inlet
. RH air inlet
CONTROL PANEL
1
A / CCM
I I
I . External temp. display I
. Coolant recirculation valve
. Coolant recirculation pump
LH blower motor & power transistor
. RH blower motor & power transistor
. LH high speed relay
Air Distribution Control
Servo motor for:
9 Centre vent flap
Foot flap
Defrost flap
Fig. 1 Schematic view A / CCM Inputs & Outputs
X300 EDM 1 Issue 1 August 1994

Climate Control Systems
14.2.16 Servo Motor Control
The system incorporates several servo motors which direct the flow of air through the air conditioning system. The
motors are driven by A / CCM signals in either a clockwise or anti-clockwise direction.
Servo motor position is monitored via
a feedback potentiometer situated within the motor housing.
The system servos comprise:
o RH and LH Air intake servos (Fresh / Recirc.).
0 Centre vent servo.
o Defrost (screen vent) servo.
0 Footservo.
0 Cool air by-pass servo.
14.2.17 Blower Motor Control
The A/ CCM controls two blower motors, delivering airflow
to the evaporator / heater unit, at variable fan speeds. The
blower motors are regulated by power transistor modules
which provide linear variation of blower speed; the blower
speed
is increased or reduced progressively in response to
vehicle speed, minimising the ram effect of forward motion.
The blower motors are inhibited when engine coolant tem
- perature is below 30°C and heating is requested.
14.2.18 Differential Control
The differential control is mounted on the facia centre vent. It is used to control the temperature difference between the
upper and lower outlets. Fig.
1 Servo
Motor
14.2.19 Heated Rear Window, Door Mirrors and Front Screen
The Heated Rear Window (HRW) function can only be activated with the ignition on and the engine running. Operation of the HRW switch operates the status condition LED on the control panel and switches on the HRWfor approximately 21 minutes. Selection of the HRW also operates the door mirror heaters for approximately 11 minutes. The operation
can be cancelled by switch re-selection or ignition off. System off does not cancel the HRW operation.
The Heated Front Screen
(HFS) function can only be activated with the ignition on and the engine running, and either
‘defrost’ mode selected or HFS selected. Each half, left and right hand split, switches on for approx. 6.5 minutes. The
operation can be cancelled by switch re-selection or ignition off. System off does not cancel the HFS operation.
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Climate Control Systems
Climate Control Module Connections, continued
35 (16-way) Input Solar sensor
36 (16
-way) Input Centre vent servo motor feedback po- tentiometer
37
(16-way) Input RH air intake servo motor feedback po- tentiometer F / R
38 (16-way) Not used
39 (16
-way) Input Cool air bypass servo motor feedback
potentiometer
I 40(16-way) llnput I Coolant temperature signal
1 41 (16-way) llnput I RH blower motor voltage feedback
I 42 (16-way) I Output I RH blower motor drive signal
I 43(16-way) I Input
I Differential potentiometer
44 (16
-way) Input Defrost servo motor feedback poten-
tiometer
45
(%-way) Input LH air intake servo motor feedback po- tentiometer - F / R
46 (16-way) Not used
47 (16
-way) Input Foot servo motor feedback potentiome-
ter
48 (16
-way) Not used
49 (16
-way) Input LH blower motor voltage feedback
50 (16
-way) Output LH blower motor drive signal
51 (26
-way) Input Compressor ON signal
52 (26
-way) Output Water valve
53 (26
-way) Output RH Blower motor relay
54 (26
-way) Output Heated front screen relays
55 (26
-way) Output Heated Door Mirror relay
Specification
Open collector R = 578, connected to
IGN, activated low
Open collector
R = IKn, connected to
IG N, activated high
Open collector R = IKQ, connected to
IGN, activated high
Voltage /temperature values
Voltage
/ temperature values
Open collector
R = IKQ, connected to
IGN, activated high
AJ16
- Ground (lock sensor not fitted)
VI2 - Ign. voltage (lock sensor fitted)
Voltage
/ temperature values
Voltage
/ temperature values
Voltage
/ temperature values
Resistance 6W.
&IO%
0% closed - IV, 100% open - 4V
Resistance 6Kn
+IO%.
0% closed - IV, IOW0 open - 4V
Pulse
width modulated signal I
OV to 3V max. I
Resistance IOW. &IO%.
Min. IV, Max. 4V
Resistance
6W. +IO%.
0% closed - IV, IOW0 open - 4V
Resistance 6W.
+IO%.
Resistance 6W. &IO%.
0% closed - IV, 10096 open - 4V
I
Battery voltage when compressor ON
1 amp at 12 volts
Load
36Q at 12V IGN, activated low
0
0
0
0
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Climate Control Systems
0 14.5 FAULT CODES
J&&: Displayed error codes are NOT compatible with Jaguar Diagnostic Equipment (JDE).
23 Refrigerant Pressure Switch Open /short circuits. Low gas charge*
24 Differential Potentiometer. Open /short circuits
31 LH Fresh
/ Recirc.
Potentiometer I I I I RH Fresh / Recirc. Potentiometer
Open / short circuit in pot. feed.
32
, In certain
circumstances, the motor can over- 0 33 Cool Air Bypass Potentiometer
34 Defrost Potentiometer travel and log further faults.
35
36 Foot Potentiometer Cycling
the ignition two or three times can cure
this.
Centre
Vent Potentiometer
41
42
I LH Fresh / Recirc. Motor
I RH Fresh / Recirc. Motor
43 Cool Air Bypass Motor
44 Defrost Motor lines. Motor flap sticking
/ jammed.
Check
for short
/ open circuits in motor drive
1 45 I Centre Vent Motor I
1 46 IFoot Motor I
W: In ambient temperatures below OOC, the system may log fault code 23 because low ambient can cause a tem-
porary low gas pressure. In ambient temperatures above 35"C, the system may log fault code 23 as temporary
high pressure can exist within the system. *
Associated Faults
Other symptoms that may exist without storing fault codes:
Airlock in system.
Water pump inoperative.
Water valve stuck closed.
Faulty engine coolant thermostat.
Broken linkage.
Blower motors
- incorrect operation.
No heat
One vent failing to open /close
Poor airflow
X300 EDM 11 Issue 1 August 1994

Climate Control Systems
Minimum differential (Red)
Maximum differential (Blue)
14.7.8 Fault Code 23
Refrigerant Pressure Switch
(A / C vehicles only)
Test the refrigerant pressure switch and harness continuity between pin 17 (22-way connector) and pin 13 (22-way
connector) A / C CM.
If there are no continuity problems, renew the A / CCM.
If there is no continuity, test the continuity of the switch between black 2-way connector pin 2 and ground (pin 1). Switch should be closed circuit at a pressure of between 2 and 30 bar. If the switch is open circuit, suspect faulty switch
or incorrect gas charge.
If the switch is operating correctly. Inspect the switch harness for open circuit or short circuit to ground. Rectify as
necessary.
Nnfe: In ambient temperatures below O"C, the system may log fault code 23 because low ambient can cause a tem- porary low gas pressure. In ambient temperatures above 35"C, the system may log fault code 23 as temporary
high pressure can exist within the system. *
=8WZkIO%
=2 WZf 10%
1 4.7.9 Fault Code 24
Differential Potentiometer
Test the 5 volt supply to differential potentiometer between pin 1 and pin 2 (ground) at the potentiometer connector.
If there is no 5V supply, inspect the harness for open circuit or short circuit to ground.
If no harness faults are apparent,
renew the A / CCM.
1ynf9: The A / CCM provides a common 5V output and ground to all servos, ie all servo potentiometers are fed by a 5V rail. If all servos are inoperable check the A/ CCM outputs and harness, renew the A/ CCM.
Check resistance between pins 1 and
2, value should be IOWZ +10% at 20°C.
If the resistance measured falls outside the said limits, renew the potentiometer.
Check resistance between pins 1 and 3 at both maximum and minimum differential potentiometer positions; adjusted
via the variable differential control thumb wheel situated between dash centre face level vents.
Position
Closed
Open
Closed
Open
I Differential potentiometer position 1 Resistance 1
Action Value Test point
Recirc. lk2
Fresh 4k8 Pin 2 ground
Recirc. 4k8
Pin
1 +5volts Fresh 1 k2
If the resistance measured falls outside the said limits, renew the potentiometer.
a
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Issue 1 August 1994 18 X300 EDM