1997 ASTON MARTIN DB7 air condition

^^?
Electrics
Airbag System
Airbag DM Fault Code 12
Low battery voltage
Normal Operation
The airbag diagnostic module (DM) monitors the
voltage at pin 1-7 which should be equal to the
battery voltage. If a voltage lower than 9 volts is
detected at pin 1-7, the airbag warning lamp will be
illuminated and fault code 12 will be flashed.
Possible Causes
Drop in battery voltage to DM pin 1-7 caused by:
• Open circuit to pin
1
-7 from the battery
• Short circuit to ground on the battery feed
circuit
• Safing sensor feed shorted to ground
• Safing sensor internal short to ground
• Faulty charge system draining the battery
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of
this
section when
working on the airbag system.

1.
Complete a battery voltage test as follows:
a) Measure the battery voltage at the battery under
KOEO and KOER conditions.
If the battery voltage is below 10.5 volts during
KOEO or below 12.5 volts during the KOER tests,
service the battery
and
charging system
as
necessary.
Retest for airbag system fau
It
code 12 and go to step
2 if the fault recurs.

2.
Complete a 12 volts supply check at the diagnostic
module:
a) Disarm the airbag system and fit airbag simulators
(6.4.21.4)
b) Disconnect the airbag diagnostic module.
c) Switch on the ignition.
d) Measurethevoltagebetween DM hamessconnector
pin 1-7 (+) and harness connector pin 1-3 (-).
e) If battery voltage is not present, go to step 3.
If battery voltage is present at pin 1-7, renew the
diagnostic module. Rearm and verify the airbag

system.

3. Check the supply fuse as follows:
a) Check fuse F16 in the passenger side fusebox RHD
(or F18 in passenger fusebox LHD).
If the fuse has not blown, check for an open circuit
between battery positive and diagnostic module
connector pin
1
-7.
If the fuse has blown. Renew the fuse and/or repair
the wiring and go to step 4.

4.
Check for a short circuit as follows:
a) Switch off the ignition. With the airbag diagnostic
module disconnected, measure the continuity to
earth from diagnostic module connector pin
1
-7 to

ground.

If no short circuit is detected, go to step 5.
Ifashortto ground isdetected, service the wiring as
necessary. Reconnect the diagnostic module and
retest to ensure that code 12 is cleared.
5. Check for a short circuit to ground on the safing
sensor wiring as follows:
a) Check for a short circuit to ground at diagnostic
module pin 1-9.
b) If a short is detected, disconnect the safing sensor
and repeat the check at diagnostic module pin
1
-9.
If a short is still detected, service the wiring from
diagnostic module pin
1
-9 to safing sensor pin 7.
c) If no short circuit is detected, change the airbag
diagnostic module. Reconnect the diagnostic
module and retest to ensure that code 12 does not
recur.
6. Rearm the airbags (6.4.21.4)
September 1996 6-85

Electrics //—>> ^^^^^^ • >^
Seat Belt Pretensioner I'•—
-"i-t.
^-^
JH—X

System Fault Strategy
No single fault may cause an unexpected deployment. The controller will supervise the pretensioner electrical
system in order to warn the driver should a fault occur. Any fault detected by the self diagnostics shall cause the SRS/
airbag warning lamp to be activated, and in some cases the pretensioner control module to enter shutdown mode.
In shutdown mode, the energy of the reserve capacitors shall be discharged to avoid unintended deployment.
As the ignition is switched on, the pretensioner controller will directly discharge the energy capacitors. When the
start up procedure is completed without detecting any faults, the DC/DC converter will be activated allowing the
capacitors to be charged. The system shall be fully active within
11
secondsafterswitchingthe ignition on providing
that no faults are detected.
All system faults monitored by the controller are filtered in software to avoid fault warnings due to transient electrical
disturbances.
If a fault which could lead to inadvertent deployment is detected by the microprocessor, a software shutdown will
be generated. However, a leakage to an earth or positive potential in the pretensioner output circuit shall not cause
the controller to enter shutdown mode.
If a permanent short of the ignition transistor occurs, a shutdown shall be generated by the hardware circuit. If a
shutdown occurs, the system shall be unable to deploy the pretensioner after a period of 3 seconds (i.e. capacitors
discharged to under minimum deployment voltage).
WARNING: To avoid the possibility of personal injury caused by accidental deployment of the pretensioner,
disconnect the vehicle battery and wait at least 10 minutes for all voltages to fully discharge before working on
the pretensioner
system.
This
covers the possibility of the normal capacitor discharge circuits being inoperative
and failing to discharge the capacitor when instructed to do so.
WA RNING: Do not make any electrical measurements on the pretensioner squib. Electrical measurement devices
can induce sufficient voltage to cause unintentional firing of the pretensioner assembly
If the module enters shutdown mode, all diagnostic functions are stopped, but the communications link remains

active.
A fault code corresponding to the cause of the problem may be read by the PDU.
Assembly/Removal/Service I nstructions
WARNING: In the event of a vehicle impact where the airbags and the seatbelt pretensioner (if fitted) are
deployed, the following actions MUST be performed:
Check the condition of the
seatbelts,
steering wheel, steering column, all connections to airbags, and the column
switchgear connectors for integrity and damage. If in any doubt, replace suspected parts for new parts.
Replace both crash
sensors,
the safing sensor and the seatbelt pretensioner module (if fitted).
On completion of all repair procedures, switch on the ignition and check that the Airbag/SRS warning light
comes

on when the ignition is switched on and extinguishes after approximately six seconds indicating satisfactory
completion of the airbag and pretensioner
system
self
tests.

Vehicles for the North American, Australian and Japanese markets are fitted with drivers seat belt pretensioner
systems and are fitted with a shorting plug in the yellow connector adjacent to the pretensioner control module.
Vehicles for other markets do not have drivers seat belt pretensioners fitted but have a blanking plug in the yellow
connector adjacent to the pretensioner control module.
6-102 September 1996

Body and Trim //-->> ^izz^^ ' ^ ^
Body Repair ' —^^ '-^ >^-/
Body Repair
Introduction
This section contains information for the body repair and rectification of the vehicle. Wherever possible the vehicle
must be returned to its original manufactured condition. Following repair the vehicle must be fully checked and, if
necessary, the braking system and steering must be fully reset.
Health and Safety
Ensure that the correct working practices are established before beginning work.
Observe that the correct working practices are followed whether they be legislative or common sense.
Be aware of the potential risks of using materials used in the manufacture and repair of vehicles and take the
appropriate precautions.
Warning: Make sure that the working practices for the air conditioning
system
are followed: do not vent the refrigerant
directly into the atmosphere and always use the approved recovery/recycle /recharge equipment, always wear
suitable protective garments to prevent injury to the eyes and the skin.
Potential Risks
Paint
If the organic solvents, contained in paints, are inhaled for any length of time damage can be caused to the liver,
kidneys, respiratory tract and the digestive system.
Prolonged exposure to isocyanates can cause lung sensitisation and asthma-like symtoms can develop with
subsequent re-exposure to even low concentrations.
Solvent inhilation can cause dizziness or loss of consciousness.
Inhilation of spray dust and sanding debris can cause lung damage.
Paint activatorsand additives will damage the eyesor can cause dermatitis if allowed to splash and come into contact
with these areas. Peroxide and acid catalysts can cause burns.
Applied heat
There is considerable risk of damage to the eyes and skin when welding or flame cutting.
Fire is a serious danger as many materials and fluids in the vehicle are inflammable.
Toxic and dangerous fumes can be liberated when the following are subjected to heat; expanded foam, corrosion

protection,
adhesive and sealing compounds,
trim,
seat material and paints that contain isocyanates.
When heated to
a
temperature of 300°C, polyu rethane based compounds can
1
iberate small quantities of isocyanate.
Many types of nitrogen containing chemicals may be liberated as breakdown products, these chemicals can
contain isocyanates, oxides of nitrogen and hydrogen cyanide.
Potentially toxic or asphyxiant fumes and gases are produced by welding, for example; zinc oxide with zinc coated
panels and ozone gas from the MIC process.
Metal repair
There is considerable risk of damage to the eyes, ears and skin when metal cutting, forming and dressing is being
carried out.
Soldering may be hazardous because of heat generated fumes and skin contact with the materials.
7-2 May 1996

Body and Trim
Body Repair ^^
Steel Body Parts - Repair^ Remove and
Replace
Removal

1.
Expose the resistance spot
weld.
For those spot
welds that are not obviously visible use a rotary
wire brush fitted to an air drill or a hand held wire

brush.

9.
Prepare the new panel joint edges for welding by
cleaning to bright metal, both interior and exterior
edges.
Apply weld through primer or inter-weld sealer to
all surfaces to be resistance spot welded.
Where appropriate, apply metal-to-metal adhesive
or sealer in accordance with the manufacturer's
instructions.
Caution: Do not
burn
off undersea I,
use a
'hot knife' or
a

suitable solvent.
2. Cut out the spot welds using aZipcutter or roto-Bor.
At this point it may be necessary to cut out the bulk
of a panel using a pneumatic saw.
Note: On
some
panels,
before removing the bulk of the
panel, brazed
areas
and MIC welded
seams
should be
removed.
3. Separate the spot welded joints and remove the
panel remnants.
Preparing Old Surfaces

1.
Remove the weld nuggets with a sander and 36 grit
disc.

2.
Clean all flanges to a bright smooth finish.
3. Straighten existing panel joint edges as required.
Preparing New Surfaces

1.
Mark off the area of the new panel and cut to size
leaving approximately two inches overlap on the
existing panel

2.
Offer up the new panel or section and align it with
the associated parts.
3. Clamp the panel into position.

4.
Where necessary, cut the new and original panels
to form a but joint.
5. Remove all clamps and the new panel.
6. If required, apply the inner panel protection and or
sound insulation.
Panel Alignment

1.
Align the replacement panel with the associated
panel and clamp it in position.

2.
With certain panels it may be necessary to tack
weld or use PK screws.
Welding

1.
MIC tack the butt joints.

2.
Re-check the alignment and the panel contours as
necessary.
3. Select the correct arms for resistance spot welding
and ensure that the tips are correctly trimmed.
Note: It
is
recommended that
the arms are
not more than
12 in (300 mm) in length.

4.
Test the equipment for satisfactory operation using
test coupons.
In the absence of test equ ipment
a
satisfactory weld
can be verified by pulling the test coupons apart
and viewing the welded condition.
5. Resistance spot weld where required. Note the
presence of zinc coated panels and treat as
previously described.
6. Dress back all MIC tack welds.
7. MIG seam weld the butt joints.
8. Dress all welds as required.
9. Final brazeand lead load as necessary priorto paint
preparation.
7-4 May 1996

in:!M3^^?
Air Conditioning
Contents
Contents
General Description 8-5
Specifications 8-5
Climate Control System 8-6
System Description 8-7
Special Servicing Tools and Equipment 8-7
Working Practices 8-8
General 8-8
Handling Refrigerant 8-8
Handling Lubricating Oil 8-8
System Maintenance 8-8
Temperature Distribution System 8-9
Fan Speed Control (Mode Switch) 8-10
Face Level Temperature Differential 8-10
Temperature Rotary Control 8-10
Refrigeration Cycle 8-11
System Protection 8-12
General System Procedures 8-12
Leak Test 8-12
Charge Recovery (System Depressurisation) 8-12
Evacuating the System 8-13
Adding Compressor Lubricating Oil 8-13
Adding Refrigerant 8-14
Functional Check 8-15
System Trouble Shooting 8-1 7
Electronic Control Module (ECM) 8-19
In Car Controls 8-21
Temperature Demand Switch 8-21
Face Level Differential Controller 8-21
Air Conditioning Function Switch 8-22
Fan Speed Control Switch (Mode Switch) 8-23
Temperature Sensors 8-23
Evaporator Sensor 8-24
Motorised In-Car Aspirated Sensor 8-24
Water Temperature Switch 8-25
Blower Motors 8-25
Potentiometers 8-26
Servo Motors 8-27
Vacuum System 8-28
Pressure-Temperature Graphs 8-29
May 1996 8-1

Air Conditioning
Contents '=2?
System Fault Diagnosis
Fault Finding
Blower Motor Test
Open Water Temperature Switch Needs
Short Water Temperature Switch Leads
Refrigeration
Compressors
Compressor Clutch Control
Trinary Switch
Condenser
Receiver-Drier
Evaporator
Expansion Valve
Sanden Compressor SD7H15
Manifold Gauge Set
System Checking with the Manifold Gauge Set
Evacuating the Manifold Gauge Set
Connecting the Manifold Gauge Set
Stabilising the System
Purging the Test Hoses
Leak Test
Manifold Gauge Set Check Procedures
Refrigerant Slightly Low.
Refrigerant Excessively Low.
Air In The System.
Compressor Malfunction
Moisture in the System
A Large Amount of Air in the System.
Expansion Valve Malfunction.
Expansion Valve Malfunction
Restriction in the High Pressure Side.
Torque Levels for the Hose Connections
8-30
8-33
8-33
8-33
8-34
8-35
8-35
8-35
8-35
8-36
8-36
8-36
8-37
8-39
8-39
8-39
8-39
8-40
8-40
8-41
8-41
8-42
8-42
8-43
8-44
8-45
8-45
8-46
8-46
8-47
Air Conditioning Procedures
Depressurising
Recovering Refrigerant
Evacuating and Recycling the Refrigerant
Recharging the System
Compressor Oil Check
8-47
8-47
8-48
8-49
8-49
8-2 May 1996

^7
Air Conditioning
Contents
Repair Procedures
8.1.01.1 Compressor Removal/Renewal 8-51
8.1.02.1 Field Coil Renewal 8-52
8.1.03.1 Renew Gasket Kit 8-52
8.1.04.1 Valve Plate Renewal 8-53
8.1.05.1 Expansion Valve Renewal 8-54
8.1.06.1 Hose-Compressor to Evaporator Renewal 8-55
8.2.01.1 Air Conditioning Unit Renewal 8-55
8.2.02.1 Evaporator Unit Renewal 8-56
8.2.03.1 Upper Servo Feedback Potentiometer Renewal 8-57
8.2.04.1 Lower Servo Feedback Potentiometer Renew 8-57
8.2.05.1 Upper Flap Motor Assembly Renew 8-58
8.2.06.1 Lower Flap Motor Assembly Renew 8-58
8.2.07.1 Ambient Temperature Sensor Renew 8-59
8.2.08.1 Blower Motor Driver Side Renewal 8-59
8.2.09.1 Blower Motor Passenger Side Renewal 8-59
8.2.10.1 Blower Assembly Driver/Passenger Side Overhaul 8-60
8.2.11.1 Blower Motor High Speed Relay Renewal 8-61
8.2.12.1 Water Temperature Switch Renewal 8-62
8.2.13.1 Heater Matrix Renewal 8-62
8.2.14.1 Electronic Control Module Renew 8-63
8.3.01.1 Vacuum System Solenoid Renewal 8-63
May 1996 8-3

Em^^^?
Air Conditioning
General Description
General Description
Specifications
Refrigerant
Designation
Refrigerant R134A

(HFCUAA)

Compressor
Type
&
model
SD-7H15
Charge weight
1050g±50g
Configuration
7 cylinder
Compressor Lubricants
Designation
Polyalkylene glycol
(PAG)

Standard
for
Recovery, Recharge
and
Recycle Equipment,
System Capacity
120-150
ml

Manufacturer and Type
ICI Klea
or
equivalent

Manufacturer

Sanden
155 cm^
per
revolution
Manufacturer and Type
Sanden SP
20

Feature

Recovery rate
Cleaning capability
Oil separator
Vacuum pump
Filter

Charge

Hoses
Charge pressure
Compressor Belt Tension
Type
Vee belt
Burroughs method
Clavis method
Requirement

0.014-0.062
mVmin.
(1.36 kg in 20
minutes)
15
ppm
moisture; 4000
ppm oil; 330 ppm
non-condensable gases
in air

With hermetic compressor and automatic
oil
return
2 stage
0.07
-0.127 mVmin.
Replaceable with moisture indicator
Selectable charge weight and automatic delivery
Dedicated Refrigerant R134A port connections.
Heating element
to
increase pressure
Condition and range
All figures apply
to a
cold belt.
New belt
578 to 623 N

If tension
is
below
356 N,
reset
at 512 to 534 N

New belt
147 to 153 Hz

If tension
is
below
110 Hz,
reset
at 132 to 138 Hz

Note:
The
tension
is
measured
midway between the
compressor
and crankshaft pulleys. For a new
belt,
rotate engine three
revolutions minimum and then re-check the tension.

May 1996
8-5