ECU ASTON MARTIN DB7 1997 Service Manual
[x] Cancel search | Manufacturer: ASTON MARTIN, Model Year: 1997, Model line: DB7, Model: ASTON MARTIN DB7 1997Pages: 421, PDF Size: 9.31 MB
Page 208 of 421
Electrics
Airbag System ^^2?
Airbag DM Fault Code 33
Passengers airbag circuit high resistance or open
circuit.
Normal Operation
The diagnostic module measures the resistance
across pins 2-2 and 2-3 every time the ignition is
switched on. The resistance should be 0.9 to 1.1Q.
If the total resistance in the passengers airbag
circuit exceeds 4.0Q, fault code 33 will be declared
and the airbag lamp will be illuminated.
Note:
The
nominal
resistance
of the airbag simulator
is
2.5£2,
therefore
expect
a
total circuitresistancereadingof
2.4 - 2.6Q with the simulator
fitted.
Caution: The passenger airbag connector contains
shorting bars which short circuit pins 1 and 3 of
both sides of the connector when disconnected.
DO NOT REMOVE THE AIRBAG SHORTING
BAR
UNDER ANY CIRCUMSTANCES.
The harness shorting bar may be temporarily
removed during the following resistance checks.
Possible Causes
• Open circuit or high resistance in the wiring
harness
• Open circuit or high resistance in the passenger
airbag module.
• Defective diagnostic module
WARNING: Do not attempt a direct resistance
check on the airbag module. Accidental
deployment can occur due to the induced voltage
from the measuring equipment.
Fault Analysis
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
2.
Disconnectthediagnostic module and remove the
plastic wedge from connector 2 (black). Measure
the resistance between pins 2-2 and 2-3. The
resistance should be 2.4 - 2.6Q.
if the resistance is 2.4 - 2.6Q, go to step 3.
Ifthe resistance is not in the range 2.4-2.6S2, isolate
the continuity problem noting the following:
a) In the diagnostic module connector, pin 2-2 is
shorted to pin 2-3 by a shorting link when plug
2 of the diagnostic connector is removed.
Removal of the plastic wedge from the plug wi
11
remove this short circuit.
b) At the airbag module harness connector, pin 1
is shorted to pin 3 when the airbag is
disconnected. Removal of the plastic wedge
from the plug will remove this short circuit.
c) The shorting link fitted in the airbag module
connector will short pin 1 to pin 3 when the
airbag is disconnected. Do not attempt to
remove
this
shorting link or the plastic wedge.
Do not attempt
to
measure the resistance of the
airbag module.
c) Carefully replace all plastic wedges on
completion of the circuit checks.
3. The fault is therefore in either the airbag module or
in the airbag diagnostic module.
Substitute a known good diagnostic module. If
code 33 recurs with the airbag simulator fitted,
there is still a fault in the wiring or the simulator.
Ifthe fault code 33 does not recur, rearm the airbags
(6.4.21.4) and retest.
If fault code 33 recurs with the airbag module fitted,
the airbag module is faulty. Replace the passengers
airbag module (7.8.02.6).
6-92 September 1996
Page 209 of 421
in:m3'^?
Electrics
Airbag System
Airbag DM Fault Code 34
Drivers airbag circuit low resistance or short circuit.
Normal Operation
The diagnostic module measures the resistance
across pins 2-5 and 2-4 every time the ignition is
switched on. The resistance should be 1.6 to 1.8Q.
This value is made up of the airbag
1
.OQ and the
cable reel cassette windings 0.3-0.4£2 per winding.
If the total resistance in the passengers airbag
circuit falls below 0.7Q, fault code 34 will be
declared and the airbag lamp will be illuminated.
Note: The nominal
resistance
of the airbag simulator is
2.5Q, therefore expect
a
total circuit resistance readingof
3.1 -
3.3£2
with the simulator
fitted.
Caution: The drivers airbag connector contains
shorting bars which short circuit pins 1 and 3 of
both sides of the connector when disconnected.
DO NOT REMOVE THE AIRBAC CONNECTOR
SHORTING BAR UNDER ANY CIRCUMSTANCES.
The airbag harness shorting bar may be temporarily
disabled during the following resistance checks.
Possible Causes
• Poorly mated cable reel cassette connector. If
the connector is poorly mated, the shorting bars
may not be fully retracted.
• Faulty shorting bar may short circuit 2-4 and 2-
5 together.
• Short circuit in the cable reel cassette windings.
• A short across the airbag terminals in the airbag
module.
Fault Analysis
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Disconnect the diagnostic module and remove the
plastic wedge from connector 2 (black). Measure
the resistance between pins 2-5 and 2-4. The
resistance should be 3.1 - 3.3Q.
If the resistance is 3.1 to 3.3Q, go to step 4.
If the resistance is below 3.1 - 3.3Q, go to step 3.
Disconnect the cable reel cassette connector at the
steering column and remove the plastic wedge.
Measure the resistance from pins 2-4 and 2-5 at the
diagnostic module connector.
If the resistance is infinity, check the cable reel
cassette for short circuits. Replace the column
switchgear assembly if necessary. Refit the plastic
wedges. Reconnect the diagnostic module. Clear
the code 34. Rearm the airbags (6.4.21.4).
If the resistance is less than infinity, replace the
main airbag harness. Refit the plastic wedges.
Reconnect the diagnostic module. Clear the code
34.
Rearm the airbags (6.4.21.4).
Since the circuit resistance is in specification, the
fault must lie in the diagnostic module or in the
airbag module.
Substitute a known good diagnostic module. If
code 34 recurs with the airbag simulator fitted,
there is still a fault in the wiring or the simulator.
If the fault code 34 does not recur, rearm the airbags
(6.4.21.4) and retest.
If fault code 34 recurs with the airbag modulefitted,
the airbag module is faulty. Replace the drivers
airbag module (4.5.01.3).
September 1996 6-93
Page 210 of 421
Electrics
Airbag System ^^?
Airbag DM Fault Code 35
Passengers airbag circuit low resistance or short
circuit.
Normal Operation
The diagnostic module measures the resistance
across pins 2-2 and 2-3 every time the ignition is
switched on. The resistance should be 0.9 to
1.1Q..
If the total resistance in the passengers airbag
circuit falls below 0.7S2, fault code 35 will be
declared and the airbag lamp will be illuminated.
f^ote:
The
nominal
resistance
of the airbag simulator
is
2.5£2,
therefore expect
a
total circuit
resistance
reading of
2.4 - 2.6Q with the simulator fitted.
Caution: The passengers airbag connector contains
shorting bars which short circuit pins 1 and 3 of
both sides of the connector when disconnected.
DO NOT REMOVE OR DISABLE THE AIRBAG
CONNECTOR SHORTING BAR UNDER ANY
CIRCUMSTANCES.
The airbag harness shorting bar may be temporarily
disabled during the following resistance checks.
Possible Causes
• Poorly mated airbag harness connector. If the
connector is poorly mated, the shorting bars
may not be fully retracted.
• Faulty shorting bar may short circuit 2-2 and 2-
3 together.
• A short across the airbag terminals in the
passengers airbag module.
Fault Analysis
1.
Disarm the airbag system and check the security of
the passengers airbag module connector before
disconnecting.
If the connector is secure, complete the disarming
procedure, fit the airbag simulators (6.4.21.4). Go
to step 2
If the connector is insecure, service as necessary,
clear the code 35, rearm the airbags. Check that
code 35 does not recur.
2.
Disconnectthediagnostic module and removethe
plastic wedge from connector 2 (black). Measure
the resistance between pins 2-2 and 2-3. The
resistance should be 2.4 - 2.6Q.
If the resistance is 2.4 - 2.6Q, go to step 4.
If the resistance is below 2.4 - 2.6fl, go to step 3.
3. Disconnect the airbag simulator at the passengers
airbag module and remove the plastic wedge from
the harness connector. Measure the resistance
between pins 2-2 and 2-3 at the diagnostic module
connector.
If the resistance is infinity, the airbag harness is
good at this time. Swap the airbag simulators at the
drivers and passengers airbag connectors. Repeat
the resistance check. If the resistance is less than
infinity, there is a fault in the passengers airbag
harness connector. Service the connector or replace
the harness as necessary. Refit the plastic wedges.
Reconnect the diagnostic module. Clear the code
35.
Rearm the airbags.
If the resistance is less than infinity, service the
bulkhead harness as necessary. Refit the plastic
wedges. Reconnect the diagnostic module. Clear
the code 35. Rearm the airbags (6.4.21.4).
4.
Since the circuit resistance is in specification, the
fault must lie in the diagnostic module or in the
airbag module.
Substitute a known good diagnostic module. If
code 35 recurs with the airbag simulator fitted,
there is still a fault in the wiring or the simulator.
If the fault code 35 does not recur, rearm the airbags
(6.4.21.4) and retest.
If fault code 35 recurs with the airbag module fitted,
the airbag module is faulty. Replace the passengers
airbag module (7.8.02.6).
6-94 September 1996
Page 211 of 421
Electrics
Airbag System
Airbag DM Fault Code 41
Right hand crash sensor feed or return open circuit.
Airbag DM Fault Code 42
Left hand crash sensor feed or return open circuit.
Normal Operation
The diagnostic module constantly measures the
voltage at pins
1
-2 and
1-11.
The voltage should be
10±1 volt. The two wires are connected together
within the right hand crash sensor. If the voltage at
1-2 falls below that at 1-11, an open circuit has
occurred.
Fault code 41 will be declared and the
airbag lamp will be illuminated.
Normal Operation
The diagnostic module constantly measures the
voltage at pins
1
-6 and
1
-12.
The voltage should be
10±1 volt. The two wires are connected together
within the left hand crash sensor. If the voltage at
1
-
5 falls below that at 1-12, an open circuit has
occurred.
Fault code 42 will be declared and the
airbag lamp will be illuminated.
Possible Causes
• Open circuit in the wires from diagnostic module
pins
1
-2 or
1 -11
to the right hand crash sensor.
• An open circuit within the right hand crash
sensor across pins 1 and 2 of the sensor
connector.
Fault Analysis
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
2.
Disconnect the diagnostic module and check
continuity between pins 1-2 and 1-11.
If the resistance is significantly greater than OQ, go
to step 3.
If the circu it resistance
is
OQ.,
the
fau It
is intermittent.
Manipulate the harness, particularly in the area of
the sensor connector and the crash sensor harness
to bulkhead harness connector, to identify the
location of the open circuit. Service the circuit as
necessary.
3. Check the right hand crash sensor connector for
security and service the connector if necessary.
If the connector is secure, disconnect and check
continuity from pin 1 to pin 2 of the sensor.
If the resistance is
h igh
or
an
open circuit
is
detected,
replace the crash sensor.
If the sensor continuity is good (0^2), service the
crash sensor loom or bu Ikhead harness
as
necessary
to remove the high resistance or open circuit.
4.
With the airbag simulators in circuit and all
connectors in place, clear the code
41.
Switch off
and then on again to check that the airbag warning
lamp comes on at 'ignition on' and extinguishes
after approximately six seconds.
5. Switch off and rearm the airbags (6.4.21.4)
3.
Possible Causes
• Opencircuitinthewiresfromdiagnosticmodule
pins
1
-6 or
1
-12 to the left hand crash sensor.
• An open circuit within the left hand crash sensor
across pins 1 and 2 of the sensor connector.
Fault Analysis
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Disconnect the diagnostic module and check
continuity between pins 1-6 and 1-12.
If the resistance is significantly greater than OQ, go
to step 3.
If the circu it resistance
isO£2,
the fault is intermittent.
Manipulate the harness, particularly in the area of
the sensor connector and the crash sensor harness
to bulkhead harness connector, to identify the
location of the open circuit. Service the circuit as
necessary.
Check the left hand crash sensor connector for
security and service the connector if necessary.
If the connector is secure, disconnect and check
continuity from pin 1 to pin 2 of the sensor.
If the resistance is high or
an
open circuit is
detected,
replace the crash sensor.
If the sensor continuity is good (OQ), service the
crash sensor harness or bulkhead harness as
necessary to remove the high resistance or open
circuit.
With the airbag simulators in circuit and all
connectors in place, clear the code 42. Switch off
and then on again to check that the airbag warning
lamp comes on at 'ignition on' and extinguishes
after approximately six seconds.
Switch off and rearm the airbags (6.4.21.4).
September 1996 6-95
Page 212 of 421
Electrics
Airbag System o
--i.
D^?
Airbag DM Fault Code 44
Right hand crash sensor incorrectly mounted.
Normal Operation
The diagnostic module constantly measures the
resistance between pins 2-8 (RH crash sensor
ground) and
1
-3 (airbag DM system ground). If the
resistance rises above 2Q, fault code 44 is declared
and the airbag warning lamp is illuminated.
Possible Causes
• Loose sensor mounting or an accumulation of
dirt or corrosion at the sensor mountings.
• An open circuit or loose wire from DM pin 2-8
to the sensor.
• An open circuit wire or loose rivet within the
sensor.
Fault Analysis
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Disconnect the diagnostic module and check
continuity between pins 1-3 and 2-8.
If the resistance is significantly greater than
OQ,,
go
to step 3.
Ifthe circuit resistance
is
OQ,thefault is intermittent.
Manipulate the harness, particularly in the area of
the sensor connector and the crash sensor harness
to bulkhead harness connector, to identify the
location of the open circuit. Service the circuit as
necessary.
Check the right hand crash sensor mounting for
security and corrosion.
If neither problem is evident, go to step 4.
If either problem is evident, remove, clean and
resecure the sensor. Reconnect the diagnostic
module. Switch on and clear the code 44. Switch
off and then on again to check that the airbag
warning lamp comes on at 'ignition on' and
extinguishes after approximately six seconds.
4.
Check the right hand crash sensor connector for
security and service the connector if necessary.
If the connector is secure, disconnect and check
continuity from pin 1 to pin 2 of the sensor.
Ifthe resistance is high or
an
open circuit isdetected,
replace the crash sensor. Go to step 5
If the sensor continuity is good (OQ), service the
crash sensor harness or bulkhead harness as
necessary to remove the high resistance or open
circuit. Go to step 5.
5. With the airbag simulators in circuit and all
connectors in place, clear the code 44. Switch off
and then on again to check that the airbag warning
lamp comes on at 'ignition on' and extinguishes
after approximately six seconds.
6. Switch off and rearm the airbags (6.4.21.4)
6-96 September 1996
Page 213 of 421
"3^=2?
Electrics
Airbag System
Airbag DM Fault Code 45
Left hand crash sensor incorrectly mounted.
Normal Operation
The diagnostic module constantly measures the
resistance between pins2-9 (LH crash sensor ground)
and
1
-3 (airbag DM system ground). If the resistance
rises above 2£2, fault code 45 is declared and the
airbag warning lamp is illuminated.
Possible Causes
• Loose sensor mounting or an accumulation of
dirt or corrosion at the sensor mountings.
• An open circuit or loose wire from DM pin 2-9
to the sensor.
• An open circuit wire or loose rivet within the
sensor.
Fault Analysis
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
2.
Disconnect the diagnostic module and check
continuity between pins 1-3 and 2-9.
If the resistance is significantly greater than OQ, go
to step 3.
If thecircuit resistance
is
OQ,
the fault is intermittent.
Manipulate the harness, particularly in the area of
the sensor connector and the crash sensor harness
to bulkhead harness connector, to identify the
location of the open circuit. Service the circuit as
necessary.
3. Check the left hand crash sensor mounting for
security and corrosion.
If neither problem is evident, go to step 4.
If either problem is evident, remove, clean and
resecure the sensor. Reconnect the diagnostic
module. Switch on and clear the code 45. Switch
off and then on again to check that the airbag
warning lamp comes on at 'ignition on' and
extinguishes after approximately six seconds.
4.
Check the left hand crash sensor connector for
security and service the connector if necessary.
If the connector is secure, disconnect and check
continuity from pin 1 to pin 2 of the sensor.
If the resistance is high or
an
open circuit isdetected,
replace the crash sensor. Go to step 5
If the sensor continuity is good (OQ), service the
crash sensor harness or bulkhead harness as
necessary to remove the high resistance or open
circuit. Goto step 5.
5. With the airbag simulators in circuit and all
connectors in place, clear the code 45. Switch off
and then on again to check that the airbag warning
lamp comes on at 'ignition on' and extinguishes
after approximately six seconds.
6. Switch off and rearm the airbags (6.4.21.4)
September 1996 6-97
Page 217 of 421
5^^?
Electrics
Seat Belt Pretensioner
The Seat Belt Pretensioner System (where fitted)
Description
The DB7 seat belt pretensioner system operates the drivers seat belt pretensioner in conjunction with the Airbag
system.
The seat belt pretensioner control module is located under the right hand seat, beside the right hand seat
control module.
The pretensioner control module calculates changes in vehicle speed using an input signal from an accelerometer.
When a collision is detected (Rapid reduction in vehicle speed) and the safing sensor in the airbag system is also
activated,
the pretensioner charge
is
fi red usingelectrical energy stored in a capacitor within the pretensioner control
module. Firing of the pretensioner charge applies additional tension to the drivers seat belt.
The airbag and seat belt pretensioner systems share the SRS (Airbag) warning lamp. Any fault detected by the
pretensioner control module is indicated by constant illumination ofthe
SRS
(Airbag) warning lamp. Flashing of the
SRS warning lamp indicates a fault in the airbag system.
Should both systems develop faults, the pretensioner system will permanently illuminate the warning lamp. This
would mask the airbag system warning indication. Therefore, rectify the pretensioner fault and then retest for faults
in the airbag system
The pretensioner control module can log up to 10 diagnostic trouble codes together with a time since each fault was
alerted to the driver. Each
fau It
wi
11
be identified as 'Permanent' or 'Intermittent' on the PDU diagnostic trouble codes
screen.
System Connections
DB7 is fitted with an Autoliv ECS or RC5 Pretensioner Control Module. The Pretensioner Control Module has an 18
pin connector featuring six shorting bridges. The mating halves of the connector may be securely locked using a
double mechanical locking system.
The following pins on the control module connector are used in the Aston Martin seat belt pretensioner system:
Pin 1 Ground
' ' "L Pin 2 Airbag Warning Lamp
Pin 11 Drivers airbag positive
Pin 12 Drivers airbag negative
Pin 14 Serial communications
Pin 15 12 volt positive feed
Case Ground
15.
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16 illn
^
Note: Pins
1
-2, 3 -4, 5 -6, 7 -8,9 -
10
and 11-12
are
shorted
together
by internal shorting links within the connector when
it
is
disconnected.
The
short circuits may
be
temporarily
overcome
for fault analysis
purposes
by inserting
a
suitable non-metallic
cheater
(the
sBfTiG
size
3s
the
p€gs
in the controller connector) into the rectsngul^r hole opposite the relevsnt p3ir of pins.
September 1996 6-101
Page 219 of 421
'^^
Electrics
Seat Belt Pretensioner
6.6.26.1
Pretensioner Control Module -
Renew
Read the warnings given in system fault strategy
and service instructions on the previous page before
starting the following procedure.
Procedure
1.
Disconnect the battery ground (black) lead and
wait at least 10 minutes for the pretensioner power
supply to fully discharge before working on the
pretensioner system.
Note:
The
vehicle battery must
be
disconnected within
12
seconds
of switching off
the
ignition to avoid the alarm
siren sounding.
2. Motor the right front seat to its rearmost position.
3. Remove the floor carpet and the ECU cover.
4.
Disconnect the pretensioner control module
connector (orange connector with black safety
clip).
5. Remove 3 flange screws securing the module,
noting the position of the earth strap.
6. Fit the new pretensioner control module with the
connector facing to the rear and secure with 3
flange screwsensuringthatthe earth strap is secured
with the outboard rear screw.
7. Connect the orange connector to the control
module.
8. RefitandsecuretheECU cover and the floor carpet.
9. Reconnect the battery ground (black)
lead.
Note:
The
vehicle clock and the window control unit will
need
resetting
after completion of this procedure.
10.
Switch on the ignition and check that the airbag
warni ng I ight comes on when the ign ition
is
switched
on and extinguishesafterapproximately sixseconds
indicating satisfactory completion of the
pretensioner and airbag system self tests.
6.6.24.1
Pretensioner Assembly Renew
Read the warnings given in system fault strategy
and service i nstruaions on the previous page before
starting the following procedure.
1.
2.
4.
Procedure
Motor the drivers seat to its rearmost position.
Disconnect the battery ground (black) lead and
wait at least 10 minutes for the pretensioner power
supply to fully discharge before working on the
pretensioner system.
Note: Disconnect the battery within 12 seconds of
switchingoffthe ignition to avoid the alarm siren sounding.
Remove the pretensioner trim cover. Unbolt the
drivers seat. Tip the seat rearwards and disconnect
the seat and pretensioner squib connectors.
Release one bolt at the
base
of the seat belt
stal k
and
remove the pretensioner assembly.
Ensure that the safety clip is fitted to the connector
at the pretensioner squib. Fit the new assembly,
locating the anti-rotation peg into the rear hole of
the mounting bracket. Secure the assembly with
one bolt. Torque the bolt to 35Nm.
Safety Clip in place
5. Route the pretensioner lead between the seat and
the frame. Reconnect the seat and pretensioner
connectors. Ensure that the pretensioner connector
safety clip is secured. Refit the drivers seat and
loosely secure.
6. Reconnect the battery ground (black)
lead.
Note:
The
vehicle clock and
the
window control unit will
need
resetting
after completion of this procedure.
7. Switch on the ignition and check that the airbag
warn i ng I ight comes on when the ignition
is
switched
on and extingu
ishes
after approximately six seconds
indicating satisfactory completion of the
pretensioner and airbag system self tests.
8. Fit the front screws ensuring a 1.2mm gap between
screws and slide. Power the seat forwardTorque the
rear screws to 25 Nm. Power the seat backward.
Torque the front screws to 25 Nm.
September 1996 6-103
Page 224 of 421
Electrics
Seat Belt Pretensioner ^?
060C Warning Lamp Short Circuit
060C will be logged if the nnonitor current flow
through the SRS/Airbag warning lamp is excessive.
The warning lamp circuit is normally at 12 volts and
is switched to ground by the airbag control module
or by the pretensioner control module when one of
these control modules detects a fault.
If either control module connector is displaced and
the ignition is switched on, the warning lamp will
be illuminated via the ground shorting link between
pins!
and 2 ofthe pretensioner controller connector
or pins 4 and 5 of the airbag controller connector,
both control modules must be checked for the
appropriate DTC to isolate which circuit is at fault.
Procedure
1.
Connect the PDU to the lower diagnostic socket
and access the pretensioner control module. Verify
that an 060C code is logged and note if the fault is
shown as intermittent. Note any other codes in the
DTC log and then clear all codes. Go to step 2.
If fault code 060C is not logged, go to the diagnostics
section of the airbag system.
2.
Check the security of the pretensioner control
module connector.
If the connector is secure, go to step 3.
If the connector isdisplaced,resecu re theconnector.
Clear all logged DTCs and retest the vehicle to
ensure that the problem is resolved.
3. Access the SRS/Airbag warning lamp and check the
lamp resistance.
If the resistance is approximately
120£2,
the lamp is
good.
Refit the lamp and go to step 4.
If the resistance of the lamp is significantly less than
approximately 120^, fit a new lamp and refit the
instrument panel. Clear the logged DTCs from the
pretensioner control module and retest the vehicle
to ensure that the problem is resolved.
4.
If the checks in step 3 are good, the low circuit
resistance must be in the instrument pack or in the
control module. Replace the pretensioner control
module and reconnect all components.
6. Switch on the ignition and then test the vehicle.
If the 060C code is logged again, replace the
instrument pack.
060D Warning lamp open circuit
060D will be logged if the monitor current flow
through the SRS/Airbag warning lamp is below the
normal monitor level.
The warning lampcircuit is normally at 12 voltsand
is switched to ground by the airbag control module
or by the pretensioner control module when one of
these control modules detects a fault.
Procedure
Connect the PDU to the lower diagnostic socket
and access the pretensioner control module. Verify
that an 060D code is logged and note if the fault is
shown as intermittent. Note any other codes in the
DTC log and then clear all codes. Go to step 2.
lffaultcode060D is not
logged,
gotothediagnostics
section of the airbag system.
Switch off the ignition. Access the SRS/Airbag
warning lamp and check the lamp resistance. The
resistance should be approximately 120Q.
If the resistance is 120i2, go to step 3.
If the lamp resistance is significantly lower than
120^2,
replace the lamp. Retest the vehicle to
ensure that the problem is resolved.
Wait 10 minutes after switching off the ignition to
ensure that the pretensioner firing capacitors have
fully discharged.
Disconnect the pretensioner control module and
temporarily cheat the warning lamp shorting link.
Note: The control module harness connector has a
shorting link which short circuits the warning lamp line
(pin 2)to ground
(pin
Dwhen
the
connector
is
displaced.
Carefully insert a suitable non-metallic cheater to remove
the
short
circuit
between
pins
1
and 2 before continuing
with fault
diagnosis.
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Insert cheater hare
6-108
September
1996
Page 227 of 421
3-^?
Electrics
Seat Removal/Replacement 97.5 MY
6.6.03
Seat Removal 97.5 MY
Description
The 97.5 MY front seats are common to the DB7
Coupe
and
Volante
models.
Seat
switch
assembi ies
are located on the outboard side of both driver and
passenger
seats.
The front switch controls fore and
aft movement and the seat height adjustment. The
centre switch controls the recline adjustment. The
rear switch
controls
the
lumbar support adjustment.
The seat
heater switches are mounted on the centre
console, forward of the gear selector
lever.
Only one of
the
slide,
recline or height motors can
be driven under manual control at any one time.
Each seat switch pack is hard wired to the relevant
Seat Control
Module
beneath each
seat.
The
module
outputs are hard wired to the seat motors.
Removal
WARNING -
Seat
belt
Pretensioners
(if fitted):
To avoid the possibility
of
personal
injury
caused
by accidental deployment of the seat belt
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 detonator capacitor when
instructed
to
do
so.
Procedure
1.
Motortheseatto
its
maximum forward position and
remove the fixings at the rear of the slides.
2.
Motor the seat to its maximum rearward position
and remove the front seat slide fixings.
3. Disconnect the battery
ground
(black)
lead.
Wait at
least 10 minutes for the pretensioner power supply
to fully discharge before working on the seat if a
pretensioner is fitted.
Note: Disconnect the battery within 12 seconds of
switching off the ignition to avoid the alarm siren sounding.
4.
Disconnect the two harness connectors from the
seat control module. Also disconnect the yellow
connector from the pretensioner control module if
a pretensioner is fitted.
Figure 1. Control module connectors
5. Remove the tie straps and release the seat harness.
6. Remove the seat earth screw from the
sill.
7. Tip the seat forwards and remove from the vehicle.
Steps 10-12 Seat Belt Pretensioner vehicles only.
8. Remove the seat belt pretensioner cover (if fitted)
9. Disconnect the buckle fly-lead from the
pretensioner.
10.
Release
one
bolt at
the
base of the
seat
belt stalk and
remove the pretensioner assembly.
Reassembly and Replacement
Steps 1-3 Seat Belt Pretensioner vehicles only.
1.
Ensurethatthesafetyclipisfittedtothepretensioner
connector at the squib.
2.
Fit the assembly to the seat, locating the
anti-
rotation peg into the rear hole of the mounting
bracket.
Securethe
assembly with
one
bolttightened
to 35 Nm.
3. Route the pretensioner lead between the seat and
frame.
Refit the pretensioner
cover.
All vehicles
4.
Replace the seat in the vehicle. Reconnect and
secure the harnesses with tiestraps.
5. Reconnect the vehicle battery.
Note:
The vehicle clock and the window control units
will
need resetting after completion
of
this
procedure.
April 1997 6-127