1997 ASTON MARTIN DB7 wiring

NO COLOUR
PIN
823
8 1
824
R
2
826 RB
3
825 RO
4

AREA
A5 A5 A5 AS
SEAT HEATER
CUSHION
ELEMENT
NO COLOUR
PIN
2193
e 1
2194
R 2
2195
RB 3
2196
RO 4

AREA 26.A2 26.A2 26.A2 26.A2

in

NO COLOUR
PIN
AREA 2188
SN
1
26.B6 2 2187
S
3
26.B6

16

NO COLOUf 2187
S

2186
SN

2189
KB
2190
OG
2191
OU

2192
KR
PIN
1 ? 3 4 S
6 1
e
9 10 11
12

AREA 26.BI
26.BI
2e.C2 26.D2 26.02
26.02 RECLINE MOTOR POTENTIOMETER

Wiring Diagram
Model - Aston Martin DB7
Harness Title - Seat
Part No. B37-84651
Revision 0 Sheet 26 of 26 - 97 MY

Electrics
Airbag System =7?
Spillage and Leakage
If material is spilled or released, contact Aston
Martin Technical Support for advice on clean-up
procedures. All personnel must be kept away from
the contaminated area.
Do not dispose of contaminated propellant or
water into storm or sanitary sewers, ground water
or
soil.

Spills may be reportable to state and/or federal
authorities.
Materials must be disposed of by incineration or
chemical oxidation under carefully controlled
conditions by specially trained individuals and in
accordancewith local stateandfederal regulations.
Scrapping Vehicles with Live Airbags
when scrapping a vehicle with live airbags, first
deploy the airbags in accordance with the following
procedure. This procedure assumes that the airbag
wiring is undamaged
See Handling/Safety Information.
If the airbags are to be removed, see the airbag
module assembly/removal/servicing instructions.
Equipment required:
Four insulation displacement connectors
(scotch locks).
Charged 'slave' battery.
Two 10 metre lengths of
1
mm^ wire fitted with
crocodile clips on one end.
Procedure
WARNING: The deployment procedure must be
carried out outdoors away from other personnel.

1.
Remove any loose debris from around the airbag
modules and ensure that no flammable liquids are
present.

2.
Disconnect the vehicle battery.
WARNING: Always connect to the airbag
first,
as

the bag will deploy immediately on connection to
the battery.
3. Remove the passenger side airbag deployment
door and underscuttle panel.

4.
Remove the drivers side underscuttle panel.
5. Disconnect the airbag connector for the spiral
cassette under the fascia and at the wire (drivers

side).

6. Locate the harness connectors and cut the wires
leading from the airbag just above the mating plug
(passengers side).
Note: The harness connected between the driver's

airbag
and the connector
has
one red
feed
wire and
one

grey/orange return
wire.
The
harness
connected between
the
passenger's
airbag and the connector
has
one blue/

orange
feed wire and one
pinl return wire.
6-72 September1996

Electrics
Airbag System '=2?
Airbag System Diagnostics
System Description
The airbag system installation comprises:
Airbag Diagnostic Module
Driver and passenger airbag modules
Two front impact (crash) sensors
One 'safing' sensor
Dedicated wiring harness
SRS indicator/warning lamp
The system is designed to provide protection for
both driver and front seat passenger by automatical ly
deploying airbags in the event of
a
collision during
forward travel.
In the event of a collision, the crash and safing
sensors will operate, completing the firing circuit
and causing the airbags to inflate within 32
milliseconds. At least one crash sensor and the
safing sensor must operate to fire the airbags.
Any faults in system components, installation or
wiring will be indicated by a flashing code on the
SRS/AIRBAG warning lamp. Fault code information
may also be monitored using the PDU or scan
tool.

Component Descriptions
Airbag Diagnostic Module
The airbag diagnostic module is mounted on top of
the passenger airbag mountingcage.Thediagnostic
module contains the microprocessor which is
connected to the complete airbag system. The state
of the three system sensors, the two airbag modules
and the wiring harness is constantly monitored by
the microprocessor for faults and for sensor
activation (crash) conditions.
The diagnostic module also confirms correct supply
voltage by comparing
a
direct battery voltage input
with a similar input via the ignition switch.
The diagnostic module contains a reserve power
supply, enabling the airbags to fire even if the
supply voltage is lost due to collision damage. The
reserve power charge will be retained for
approximately one minute if the positive battery
supply is lost in a collision. An auxiliary internal
circuit known as the 'dwell enhancer' provides a
temporary ground if normal system ground was lost
in a collision.
Wiring Harness
A dedicated electrical wiring harness is used to
connect all system components to the bulkhead
harness. To allow free movement of the steering
mechanism, a cable reel cassette is used to connect
the drivers airbag in the steering wheel to the airbag
harness on the steering column.
Airbag Modules
The two airbag modules contain achargeof sodium
azide/copper oxide which wi
11
generate
a
sufficient
volume of nitrogen gas to fully inflate the airbag
when ignited by an electrical impulse. The volume
of gas is greater in the passenger side airbag due to
its larger size.
Both airbag modules, including the surrounding
trim of the drivers airbag, are non-serviceable and
once deployed, must be renewed as a complete
assembly.
Crash and Safing Sensors
The two crash sensors are mounted one at either
side of the bumper mounting cross member, outside
of the bonnet hinges.
The safing sensor is mounted in the base of the
drivers side 'A' post.
The two crash sensors and the safing sensor
determine when airbag deployment is necessary in
a crash condition.
The sensor contacts will only close when the vehicle
suffers a forward impact of sufficient force. At least
one crash sensor and the safing sensor contacts
must close before the airbags will deploy. The
doubletrigger strategy
is
used to prevent deployment
during trivial impacts such as contacts during

parking.

6-78 September 1996

Electrics
Airbag System ^^?
Airbag Diagnostic Module Connector
The wiring to the airbag diagnostic module passes through two plugs into a single socket. Plug
1
is grey coloured,
plug 2 is black. To aid in fault analysis, the diagnostic module connector pins for plugs
1
and 2, and their functions
are listed below:
Connector 1 - Grey Colour
Pin No. Colour Circuit
Connector 2 - Black
Pin No. Colour Circuit
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
1-10
1-11
1-12
LGS
ON
B
YW
B
YU
RW
-
RN
RG
KU
KG
12V Ignition Supply
RH Crash Sensor Monitor
Ground
Airbag Warning Lamp Output
Ground
LH Crash Sensor Monitor
12V Battery Power
Not Used
Safing Sensor Input
Safing Sensor Ground Monitor
RH Crash Sensor Feed
LH Crash Sensor Feed
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
-
RP
KP
KN
RP
YG
-
OP
ow
-
YP
-
Not Used
Passenger Airbag Module Feed
Passenger Airbag Module Return
Drivers Airbag Module Return
Drivers Airbag Module Feed
Safing Sensor Output Monitor
Not Used
LH Crash Sensor Ground Monitor
RH Crash Sensor Ground Monitor
Not Used
Safing Sensor Feed
Test Input
Plug 2 Piugl
/LrLrLruuTJu—LrLrLrLrLrLnj
OOO
Connector 2/12-Way/Black
YG RP 3 KP

mn

10 9 OW
Connector 1/12-Way/Grey
6 YU 5 B
12 KG 11 KU 10 RG
4 YW
I
ON LGS
0
6
12 'I J'
6
12 J
6-82 September 1996

"^p
Electrics
Airbag System
No Airbag Warning Lamp

I
noperative lamp, lamp ci rcu it or no ign ition voltage
to the diagnostics module
Normal Operation
The airbag warning lamp is designed to illuminate
for approximately six seconds when the ignition is
switched
on.
This period
is
allocated for satisfactory
performance of the airbag system self test.
Note: The a irbag warning lamp is
driven
by
the instrument

pack and not directly by the airbag diagnostic module.
The airbag diagnostic module requires an ignition
supply to pin
1
to energise the airbag warning lamp
circuit. If the warning lamp circuit is open, or the
diagnostic module does not receive an ignition
voltageatpini, the warning lamp will not illuminate.
Open circuit in the warning lamp supply, in
conjunction with another system fault, will cause
the diagnostic module to emit five tones every 30
minutes while the ignition is switched on. Repair
the faulty circuit before further diagnosis.
Note:
The
diagnostic module will not emit
the
five tone
signal if the warning lamp
is
open circuit and
there
is no

system
fault.

Possible Causes
Defective airbag warning lamp
Faulty wiring in the airbag warning lamp circuit
Loss of ignition voltage at diagnostic module pin 1.
Loss of ground at diagnostic module pin 3
Instrument pack fault
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of this section when
working on the airbag
systent.

1.
Remove the instrument pack and check the airbag
warning lamp.
If the lamp is good, go to step 2.
If the lamp is defective, replace it, switch on the
ignition and check that the lamp is now on for
approximately six seconds after ignition on.

2.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
9.
Connect the PDU. Switch on the ignition. Measure
the 12V ignition supply voltage from airbag
diagnostic connector pin
1 -1
{+) to chassis ground.
If ignition voltage is present, go to step 6. If ignition
voltage is not present, go to step 4.
Checkfuse F15passengersidefuseboxRHDorF17
passenger side fusebox LHD (Ignition supply to the
diagnostic module pin
1
-1). If the fuse is good, go
to step 5. If the fuse is replaced, go to step 6.
Check for an open circuit on the YW wire from fuse
F15 passenger sidefusebox(F17 LHD)todiagnostic
module pin 1-1. If continuity is good, isolate the
fault in the 12V supply to fuse Fl 5 (Fl 7) and then
go to step 9.
Measure the voltage from diagnostic module pin
1
-
1 to diagnostic module pin 1-3. If 12V is not
present, isolate and service the open circuit in the
diagnostic module ground to pin 1-3. Then go to
step 7.
Switch the ignition off. Set up to measure the
voltage from DM pin
1
-4 to DM pin
1
-5 during the
first six seconds after ignition on.
Switch on the ignition, the warning light signal to
the instrument pack should switch for six seconds
after a brief delay.
If the signal does not switch, the diagnostic module

is
fau Ity. Replace the modu
le,
switch on the ign ition
and check that the airbag warning lamp does light
for six seconds after ignition on.
If the signal does switch for approx. six seconds
after ignition on, the fault is in the instrument pack
or wiring, go to step 8.
Check continuity of the YW wire from diagnostic
module pin
1
-4 to instrument pack 16 way plug pin

2.

If continuity is good, service the instrument pack
and then retesttoensure correct indication from the
airbag warning lamp at ignition on.
If continuity is defective, service the wire and then
retest to ensure correct indication from the airbag
warning lamp at ignition on.
Disconnect the PDU, and rearm the airbags
(6.4.21.4). Switch on the ignition and check for
correct indications from the airbag warning lamp.
September 1996 6-83

Electrics
Airbag System [EE:^^^?
Continuous Airbag Warning Lamp
Inoperative lamp circuit or no ignition supply to the
airbag diagnostic module.
Normal Operation
The airbag warning lamp is designed to illuminate
for approximately six seconds when the ignition is
switched
on.
This period isallocated for satisfactory
performance of the airbag system self test. If after
this period, the diagnostic module detects a fault
within the system, the airbag warning lamp will
begin to flash.
Note:
The seat
belt
pretensioner system
(if fitted)
shares

the
airbag/SRS
warning lamp with
the airbag
system.
If a
seat belt pretensioner fault is
detected,
the
Airbag/SRS

warning lamp will be permanently illuminated. Ensure
thata permanently lit
lamp
is nottheresultof a pretensioner
fault before carrying out fault analysis on the airbag
system.
Poor connection or disconnection of the diagnostic
module harness may cause a short circuit from DM
pin 4 (warning lamp control) to pin 5 (ground) and
cause permanent illumination ofthe warning lamp.
Faulty operation of the diagnostic module internal
logic may fail to turn off the warning lamp control
circuit and cause constant illumination of the
warning lamp.
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.
Disarm the airbag system and fit airbag simulators
(6.4.21.4). Reconnect the battery.

2.
Inspectthe instrument pack and diagnostic module
connectors for damaged, pushed out pins, proper
location etc.
If any defects are identified, service as necessary.
Retest to ensure correct operation of the airbag
warning light.
If the connector condition and security are good,
reconnect the connectors and go to step 3.
5.
Connect the PDU to the upper diagnostic socket
and monitorthe airbag warning lamp
signal.
Switch
on the ignition.
If the signal is permanently low, suspect a short
circuit to ground on the airbag warning lamp
control line within the diagnostic module or from
diagnostic module pin
1
-4 to earth. Co to step 4.
If the signal switches low for six seconds after
ignition on but the airbag warning lamp is
permanently illuminated, suspect a fault in the
output side of the instrument pack to the airbag
warning lamp.
Disconnect diagnostic module plug 1 (slate) and
withdraw the plastic locking wedge to prevent
shorts to other circuits. Check continuity from pin
1-1 to ground.
If a short circuit to ground is detected, service the
wiring
as
necessary. Replacethe locking
wedge,
re­
insert the connector. Switch on the ignition and
check that the airbag warning lamp signal atpin 1-
4 goes high six seconds after switching on the
ignition and that the warning lamp extinguishes.
If no short circuitto ground isdetected,thediagnostic
module is faulty. Replace the diagnostic module.
Switch on the ignition and check that the airbag
warning lamp signal at pin
1
-4 goes high six seconds
after switching on the ignition and that the warning
lamp extinguishes.
Switch off the ignition. Disconnect the battery.
Rearm the airbags (6.4.21.4). Switch on the
ign
ition
and check for correct indications from the airbag
warning lamp.
6-84 September 1996

^^?
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
Airbag System ^2?
Airbag DM Fault Code 13
Airbag circuit short to ground
Normal Operation
The diagnostic modu
le
measures the voltage at pins
2-5 and 2-6. The voltage at these pins is dependant
on charging system voltage as shown in the table

belovi-.

'in 2-5
2.3V
2.4 V
2.5V
2.7V
2.8V
3.0V
3.1V
3.2V
3.4V
3.5V
3.7V
3.8V
4.0V
4.1V
4.3V
Pin 2-6
2.3V
2.4V
2.5V
2.7V
2.8V
3.0V
3.1V
3.2V
3.4V
3.5V
3.7V
3.8V
4.0V
4.1V
4.3V
Charge Volts
9.0V
9.5V
lO.OV
10.5V
11.OV
11.5V
12.0V
12.5V
13.0V
13.5V
14.0V
14.5V
15.0V
15.5V
16.0V
If the diagnostic monitor measures a voltage of 2.0
volts or less on pins 2-5 and 2-6, a fau It code 13 will
be generated and flashed to the instrument pack to
be signalled on the airbag warning lamp. Voltages
as low as 2.0 volts indicate a possible short to
ground in these circuits.
When generating a code 13 the diagnostic module
also generates a signal to blow its own internal
thermal fuse. This action disables the airbag
deployment circuit. The airbag diagnostic module
fuse is non-repairable and the module must be
replaced after repairing the short circuit, if the
voltage at pins 2-5 and 2-6 returns to normal, fault
code 51 (blown thermal fuse) will be stored in
memory.
6.
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of this section when
working on the airbag
system.

Disarm the airbag system and fit airbag simulators
(6.4.21.4)
Disconnect the airbag diagnostic module. Switch
on the ignition.
Measure the continuity to ground at the following
pins on the diagnostic module harness connector:
2-2 Passenger airbag feed
2-3 Passenger airbag return
2-4 Drivers airbag return
2-5 Drivers airbag feed
2-11 Safing sensor feed
If no short circuit is detected, go to step 4.
If
a
short circuit is detected, disconnect the relevant
airbag simulator or the safing sensor and repeat the
continuity measurement to isolate the circuit fault.
Service the wiring or replace the safing sensor as
necessary. Fit a new airbag diagnostic module and
rearm the airbags (6.4.21.4).
Check for intermittent short circuits in the cable
reel cassette. Monitor the continuity to ground at
pins 2-4 and 2-5 whilst rotating the steering from
lock to lock in both directions.
If no short circuit is detected, go to step 5.
If a short circuit is detected, replace the column
switchgear assembly. Fit a new airbag diagnostic
module and rearm the airbags (6.4.21.4).
WARNING: Do not attempt to make any electrical
measurements on the airbag
modules.
Any induced
voltage can
cause
the airbag
to
deploy with the
risk

of personal
injury.

Fit a replacement diagnostic module and
replacement airbag modules.
Caution: Do not refit
the
old
airbag
modules.
They may

be faulty and would
damage the
new diagnostic module.
Rearm the airbag system (6.4.21.4).
6-86 September 1996