stop start ASTON MARTIN DB7 1997 Workshop Manual

[n:m3^y

Component Name
Microwave Sensor
Mode Switch
Multifunction Module
Number Plate Lamp - LH
Number Plate Lamp - RH
Oil Pressure Warning Light Transducer
Output Speed Sensor (Auto)
Park Switch (Auto)
Purge Valve 1
Purge Valve 2
Radio Aerial
Radio Telephone Connector
Radio Tweeter
Radio Tweeter
Radio
Rear & Number Plate Bulb Fail Unit
Rear Fog Lamp LH
Rear Fog Lamp RH
Rear Lamp - LH
Rear Lamp - RH
Recline Motor Potentiometer
Relay - ABS Pump
Relay - Air conditioning clutch
Relay - Air Pump
Relay - Auxiliary Load
Relay - Boot Release
Relay - Courtesy Lights
Relay - Cruise Control On/Off
Relay - Drivers Seat Heater
Relay - Fan 1
Relay - Fan 2
Relay - Fan Run On
Relay - Front Fog Lamps
Relay - Fuel Pump 1
Relay - Fuel Pump 2
Relay - Gearbox Failure Warning
Relay - Headlamp Dipped Beam
Relay - Headlamps
Relay - Heated Rear Window
Relay - Horns
Relay - Ignition Load
Relay - Main
)
Location
Reference
12-1
7-9
4-2
5-3
5-3
3-17
11-12
10-1
10-3
10-4
15-4
15-3
6-7
6-5
6-6
15-11
14-2
14-5
14-1
14-6
9-7
4-8
1-17
4-14
4-4
15-9
4-11
6-1
12-3
1-20
1-19
1-18
1-6
15-7
15-8
4-9
1-5
1-7
4-15
1-16
4-10
4-12
Relays - Drivers/Passengers Seat Heaters 12-3
Relay - Rear Fog Lamps
Relay - Reverse Lamps
Relay - Sidelamps
Relay - Starter Solenoid
Relay - Stop Lamps
Reversing Lamp Switch (Man)
Reversing Light Switch (Auto)
Screen Wash Pump
4-17
15-6
1-9
1-15
15-5
11-3
10-2
1-13
Electrics
Electrical Component Location Index - Up to 97 MY
Wiring Diag.
Reference
24-C2
4-A3
8-C4
27-84
27-B6
5-C5
7-B3
21-B1
5-A4
5-A5
24-D2
25-B2
8-C3
14-C4
10-A2
25-C3
17-D2
18-D2
24-A5
24-C4
22-81
9-C4
3-A3
13-A5
9-D1
26-D3
13-A2
20-B1
16-D3
3-B6
3-B6
3-A5
1-B5
26-A2
26-A3
13-A1
1-B5
1-84
13-A4
3-A4
13-A2
13-A3
15-D3
13-A5
25-A4
1-B4
3-A4
25-A5
7-C5
21-C2
3-D1

Rep.
Op. Notes
Reference

6.6.14.2

6.5.07.4

6.4.12.1
6.9.03.1
6.9.03.1

1.5.08.1

3.4.02.2
Auto only

6.5.13.1
Auto only

6.1.14.1

6.1.14.2

6.9.08.1
6.9.09.1
6.5.17.1
6.5.17.1
6.5.05.1
6.9.10.1
6.7.02.1
6.6.07.1

5.1.15.1

6.2.06.1
6.4.13.1
6.4.14.1
6.9.11.1
6.4.15.1
6.5.18.1
6.6.15.1

1.7.16.3
1.7.16.3

1.7.16.4

6.1.04.3

6.9.12.1
6.9.12.1
6.4.16.1
Auto only

6.1.15.1
6.1.16.1
6.4.17.1
6.2.07.1
6.4.18.1
6.4.19.1

6.6.15.2

6.4.20.1
6.9.13.1
6.1.17.1
6.2.08.1
6.9.14.1
6.2.09.1

6.2.09.2

6.3.06.1

May 1996 6-21

Electrics
Electrical Component Location Index - Up to 97 MY
Component Name
Seat Belt Switch
Seat ECU - Driver
Seat ECU - Passenger
Seat Heater - Cushion Element
Seat Heater - Squab Element
Seat Heater Control Module
Seat Motor Potentiometer
Seat Pressure Pad
Seat Switch Pack - Driver
Seat Switch Pack - Passenger
Security System Aerial
Security System ECU
Side Marker Lamp - LH Front
Side Marker Lamp - RH Front
Speaker - Rear LH
Speaker - Rear RH
Speed Control Dump Valve
Start Inhibit Switch
Starter Motor Solenoid
Stop Lamp Fail
Stop Lamp/Cruise Disable Switch
Thermal Breaker - Window Lift
Throttle Potentiometer
Water Temp Sensor - Engine ECU
Water Temp Sensor - Temp Gauge
Wheel Speed Sensor - Front RH
Wheel Speed Sensor - Front LH
Wheel Speed Sensor - Rear RH
Wheel Speed Sensor - Rear LH
Window ECU - LH
Window ECU - RH
Window Switch - RH
Window Switch LH
Wiper Logic Module
Wiper Motor
Window Lift Motor
Location
Reference
13-2
6-2
6-2
12-5
12-4
6-3
9-7
12-6
6-8
6-8
2-12
15-2
5-5
5-5
6-10
6-10
1-4
10-9
3-14
15-10
11-8
4-7
3-15
3-5
3-4
13-4
13-4
13-1
13-1
12-11
12-11
2-5
2-5
4-5
1-1
12-10
Wiring Diag.
Reference
22-A3
16-A1
15-A1
22-A2
15/16-A4
22-A5
22-C2
22-D3
16-B1
15-B1
24-C2
26-B6
1-C2
1-A3
24-B2
24-C2
2-A2
21-C3
3-C2
25-A3
12-C5
9-C3
5-A3
5-C2
5-C2
29-C3
28-D4
28-D3
28-D2
17-D3
18-D3
19-A2
19-D2
9-A3
8-C3

Rep.
Op.
Reference

6.6.16.1
6.6.17.1

6.6.17.2

6.6.18.1

6.6.18.2

6.6.18.3

6.6.19.1
6.6.20.1
6.6.21.1
6.6.21.1
6.6.22.1

6.6.22.3

6.1.18.1
6.1.18.1
6.6.23.1
6.6.23.1
6.1.19.1
6.1.20.1

6.3.02.2

6.9.15.1
6.4.02.1
6.1.21.1

2.5.02.2

6.3.07.1

8.2.12.1

5.1.12.1
5.1.12.1
5.2.01.1
5.2.01.1

6.1.22.1
6.1.22.1
6.5.03.1
6.5.03.1
6.2.01.1

6.1.21.3

Notes
6-22 May 1996

Electrics
Component Index Sheet 4-97 MY ^7
Component
Name
Relay - Rear Fog Lamps
Relay - Reverse Lamps
Relay - Right Quarter Light Up
Relay - Right Quarter Light Down
Relay - Sidelights {
Relay - Starter Solenoid
Relay - Stop Lamps
Relay- Tilt Sensor
Reversing Light Switch
Screen Wash Pump
Seat Belt Stalk
Seat Belt Pretensioner Control Module
Seat Belt Pretensioner Squib
Seat ECU - Driver
Seat ECU - Passenger
Seat Fore/Aft Motor Potentiometer
Seat Heater Cushion Element
Seat Heaters - Driver
Seat Heaters - Passenger
Seat Lumbar Support Pump
Seat Pressure Pad
Seat Recline Motor Potentiometer
Seat Switch Pack - Driver
Seat Switch Pack - Passenger
Security System Aerial
Security System ECU
Side Marker Lamp - LH Front
Side Marker Lamp - RH Front
Side Marker Lamp - LH Rear
Side Marker Lamp - RH Rear
Side Repeater Lamp LH
Side Repeater Lamp RH
Speaker - Drivers Door
Speaker - Passengers Door
Speaker - Rear LH
Speaker - Rear RH
Starter Motor Solenoid
Throttle Potentiometer (Eng Sub-harness)
Tilt Sensor
Transmission Connector
Transmission Control Module (TCM)
Transmission Input Speed Sensor
Transmission Output Speed Sensor
Tyre Compressor Socket
Vapour Management Valve
Vehicle Speed Sensor (VSS)
Window ECU - Drivers Side
Window ECU - Passengers Side
Window Lift - Left Quarter Light (Volante)
Window Lift Thermal Breaker
Window Switch LH
Window Switch RH
Wiper Logic Module
Wiper Motor
6-46
Component
Location
Circuit
Reference
(see relay location chart) 8-C4 it ti It
II H U
tl 11 U
a II 11
II II II
II Ji II
II II II
7-7
15-1
15-9
4-4
15-5
4-6
4-6
15-10
7-11
7-n
7-11
16-4
7-10
15-10
7-3
7-3
16-10
4-5
16-1
16-2
16-6
16-8
13-1
13-4
5-3
5-3
5-6
5-6
3-10
3-7
7-9
16-5
4-7
17-7
17-7
17-5
15-7
8-5
6-3
6-3
17-4
6-4
17-1
17-3
7-2
17-2
' ) 17-A2
' ) 19-A4
' ) 19-A5
' ) 2-A1
' ) 2-A3
' ) 17-A1
' ) 17-A4
7-C5
3-A2
26-A3
14-A4
14-B4
23-A1
24-A1
26-C2
26-A2
23-A4
24-A4
26-D2
26-D3
26-B1
23-B1
24-B1
16-B2
17-B6
1-C2
1-82
15-C4
24-D4
2-C5
3-D5
21-C5
22-C5
15-Cl
16-B1
2-A5
5-C3
14-C4
7-A4
4-B5
7-B2
7-B3
17-C5
16-A3
15-B3
21-C3
22-C3
15-A1
12-Cl
13-C2
13-A2
11-B5
6-A1
September 1996

^=2?
Electrics
Airbag System
Eye Protection
Chemical protective goggles are recommended
where there is a possibility of eye contact with the
propellant. Safety glasses with side shields are
recommended for all other operations.
Protective Clothing
Approved protective gloves, overalls and shoes/
boots should be worn.
Handling and Storage Precautions
Do not store airbag modules near live electrical
equipment or circuitry. Store in a dry environment
at ambient temperatures.
Good housekeeping and engineering practices
should be employed to prevent the generation and
accumulation of
dusts.
Store in compliance with all
local state and federal regulations.
Driver and Passenger Airbag Modules
Assembly/Removal/Service Instructions
WARNING: In the event of a vehicle impact where the
airbags and the seatbeltpretensioner (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.

WARNING: Before starting
work,
ensure
that the ignition
switch is in position 'O' and the ignition key is

removed.
Disconnect the battery negative lead
within 12 seconds of switching off the ignition to
prevent the alarm system triggering.
As the airbag control module is equipped with a
back-up power source and due to the risk of the
airbag being inadvertently deployed, wait one
minute or longer after disconnecting the battery
before starting work on the airbag module.
• Disconnectingthe battery negative cable cancels
the memory for the 'one-touch' window down
system and stops the vehicle clock. Reset the
window memory and the clock when work is

completed.

• Never use airbags from other vehicles, always
use new parts.
• After work is completed, reconnect the battery
and perform the airbag warning light check
• Never use electrical probes to check voltage or
electrical resistance of the airbag modules.
• Disconnect the airbag before carrying out any
work on, or in the vicinity of the module, or
when using electric welding equipment.
• Always ensure that the battery negative lead has
been disconnected for at least one minute before
commencing any removal procedure.
September 1996 6-71

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

y/--^^^^3^
'—-p "^ Body and Trim
Roof Description
Volante Roof
Description
The system comprises an electrically driven hydraulic pump and two hydraulic rams for raising and lowering the

roof.
The pump is powered via two heavy duty changeover relays. Two further pairs of changeover relays power
the rear quarter windows (one pair for each window). The roof hydraulic pump is protected by a 30A fuse, the
windows by circuit breakers.
An electronic control module (ECM) is actuated by the roof switch on the centre console. The ECM controls the
operation of
both
the roof
and
rear quarter window circuits
so
that they can only be operated in
a
pre-programmed

manned.
When in operation, the ECM provides signals to the roof and to the rear quarter windows.
When the roof
switch
is moved into the open (Roof Down) position, the roof
and
rear windows move together until
approximately four seconds has elapsed. At this time, the ECM will remove power from the rear window circuits,
leaving the roof motor running. The roof motor will stop after 12 seconds (i.e. a further 8 seconds after the rear
window motors stop).
The signals will be removed from the rear window relay after 4 seconds and from the roof relay after 12 seconds
if the roof switch is held in either position for longer than 12 seconds.
In order to comply with legislation, the following features are built into the system:
If the roof switch is operated in either direction and then released before that operation is complete, the roof and
rear quarter windows will stop immediately. If, whilst the system is in operation, the ignition switch
is
turned to the
off position, the system will immediately stop.
If the roof switch is pressed again after pausing during a roof movement, the timing sequence will be as follows:

1.
If the previous direction is selected, the timing recommences from where it left off and will continue to
completion. If the ignition has been turned off, the timing will start from the beginning of its cycle.

2.
If theoppositedirection
is
selected,
the timing sequence will commence
from the beginning
of the newly selected
direction and continue to completion.
Roof and Rear Quarter Light Control
The following diagrams show the component location and the electrical control for the roof and rear quarter light
systems.
May 1996 7-7

^2?
Air Conditioning
System Recharging / Compressor Oil Check
Recharging the System

1.
Open the high side valve on the unit control panel.
If the messages PROGRAM and CHARGE are not
displayed press the CHG key to enter PROGRAM

mode.

2.
Key in the amount of refrigerant needed to recharge
the system and press ENTER.
3. Press the CHG key; the message AUTOMATIC and
the entered amount of refrigerant wi
11
be displayed.
The display counts down to zero as the charging
process proceeds. When the charging is complete
the message CPL is displayed.
If the refrigerant transfer is too slow the charging
unit emits a signal. If the message CHECK
REFRIGERANT is not displayed, close the high side

valve,
open the low side valve and start the air
conditioning system to pull the remainder of the
charge into the system.
If the refrigerant transfer will not complete and the
message CHECK REFRIGERANT is displayed, press
the HOLD/CONT key to interrupt the cycle then
reset the unit by pressing the RESET key. Recover
the refrigerant already charged into the system by
following the procedure for recovering the
refrigerant, add new refrigerant to the tank and
return to Step 1 to recharge the system.

4.
If the air conditioning system is not running start it
and let it run until the gauge pressure readings
stabilize (compare the gauge readings with the
system manufacturer's specifications).
Note:
Ensure
that the
readings
are accurate by closing
both the high and low side
valves
on the unit's control
panel.
5. Check the evaporator outlet temperature to make
sure that the air conditioning system is operating
properly (refer to the system manufacturer's
specifications for the proper temperature).
Compressor Oil Checic
Data
Special Tools
Sanden oil dipstick JD 149
Torque Figures
Oil filler plug 8-12 Nm
Procedure
Whenever a component has been replaced in the
refrigerator system or there is an obvious oil leak, the
following procedure should be carried out.
A Sanden oil dipstick and angle gauge are required in
order to carry out the check.

1.
Run the compressor for 10 minutes at engine idle

speed.

2.
Depressurise the system.
3. Lay the angle gauge across the flat surfaces of the
two front mounting lobes. Centre the bubble and
note the mounting angle.

4.
Remove the compressor from the vehicle.
3. Remove the plug from the oil filler hole
(1
Fig. 1).

4.
Rotate the counter weight (3 Fig. 1) on the front of
theclutchtoallowthedipstick(2 Fig. 1)to penetrate
to its fullest extent.
Figure 1.
5. Insert the dipstick to its stop position (4 Fig. 1). The
point of dipstick angle should be facing left.
6. Removethedipstickandchecktheoil levelagainst
the figures quoted in the chart below.
May 1996 8-49

The Aston Martin Lagonda Diagnostic System
Users Guide ^?
Engine Setup
- 95 MY

Two adjustments
may
beset with the aid of the PDU
on 95

MY vehicles.
• Throttle Potentiometer
• Idle Fuelling Trim
From
the 95 MY
Main Menu, make
and
confirm
the

following sequence
of
selections:
Diagnostics
/

Manual
or
Auto Transmission
/

Engine
/

Engine Setup
/

The following connection diagram will then be displayed.
Throttle Sensor Adjustment
- 95 MY

Note:
The
throttle stop
and
throttle cable adjustments
must
be
correct before setting
the
throttle potentiometer.
On completion
of the
engine setup connections
the
test
selection screen will
be
displayed.

1.
Select Throttle Potentiometer.

2.
Turn
the
ignition switch
to
position
II but do not

start
the
engine.
3. Monitorthethrottle potentiometer bargraph voltage
at fully closed
and
then
at
fully open throttle.

4.
The
throttle potentiometer voltage specifications

are:

Throttle Closed
0.57 -
0.59V

Throttle Full Open
4.00 +V

Cable Setup
Diagnostic Socket D
Engine Setup Connections
Tinrottle Position Sensor
Value
:
0.43V

570
600

Idle Voltage
(mV)
Make adjustments as
necessary

Throttle Potentiometer Voltage
5.
If
both voltages
are
either high
or low,
loosen
the

two throttle pot screws and adjust the potentiometer
until
the
specified voltages
are
achieved. Carefully
tighten both screws ensuringthat the potentiometer
does
not
move during tightening.
6.
If
either voltage
is
unstable
or if the
specified
voltages cannot
be
achieved, investigate the cause.
If
the
potentiometer
is
replaced,
set the new pot

using steps
3-5
above.
Note:
On
automatic vehicles,
the
kickdown switch
adjustment check follows the throttle
pot
adjustment.
9-38 September
1996

ffi:
The Aston Martin Lagonda Diagnostic System
Users Guide
Idle Fuelling Trim - 95 MY
This program is used to check and if necessary reset the
fuelling level at idle to ensure that the specified idle speed
and emission levels are attainable. The throttle
potentiometer adjustment sequence must be completed
before the fuel trim sequence can be run.
Note: The throttle setup must be completed before
attempting to set the Idle Fuelling Trim. An error in
throttle
stop,
throttle cable or throttle pot
adjustments can
cause serious
difficulties in setting the Idle Fuelling.
Select Idle Fuelling Trim from the Engine Setup

Menu.
(The PDU connections are
as
fortheThrottle
Potentiometer Adjustment.)

1.

3.
StarttheDB7engineand allow itto warm to normal
operating temperature.
Followthescreeninstructionstorunthe idle fuelling
trim procedure.
Observe the bargraphs for oxygen sensors A and B.
The bargraph indications should oscillate evenly
about the 0% position on the bargraph.
BANK

-100%

BANK

-100%

Idle
Fuel
Trim
Closed Loop Control Data
Q Idle
trim:
8%
9^B 1 1
Oxygen Sensor Fuel Trim 100%
B Idle
trim:
5% —1 1 1

«^
1 1 Oxygen Sensor Fuel
Trim
100%
Idle Fuelling Trim Display
5. Ifthebargraphindicationsarenotoscillatingevenly
about the 0% position, select the A (cylinders 1, 2
and 3) or the B (cylinders 4, 5 and 5) sensor. The
Increase/Decrease buttons will appear.
6. Adjust the fuel trim as required to achieve even
oscillation about the 0% mark for both sensors.
When the adjustment is correct, select the 4 icon
and confirm that the idle fuelling trim is correct. On
confirmation of the adjustment, the PDU will exit
from the idle fuelling program.
7. On completion of the procedure, select Exit from
the Engine Diagnostics Software.
September 1996 9-39

^^?
The Aston Martin Lagonda Diagnostic System
Users Guide
Seat Belt Pretensioner Diagnostics
(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 underthe right hand seat, beside the
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) the pretensioner charge is
fired using electrical 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 fault will be
identified as 'Permanent' or 'Intermittent' on the PDU
diagnostic trouble codes screen.
System Connections
The Autoliv RC5 Pretensioner Control Module has an
18 pin connector featuring six shorting bridges. The
mating halves ofthe 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
Pin 2
Pin n
Pin 12
Pin 14
Pin 15
Case
September 1996
Ground
SRS/Airbag Warning Lamp
Drivers airbag positive
Drivers airbag negative
Serial communications
12 volt positive feed
Ground
System Fault Strategy
No single fault may cause an unexpected deployment.
The controller will supervise the airbag/pretensioner
electrical system in order to warn the driver should a
fault occur. Any fault detected by the self diagnostics
shall cause the airbag warning lamp to be activated,
and in some cases the pretensioner control module to
enter shutdown mode. In shutdown mode, the energy
ofthe reserve capacitors shall be discharged to avoid
unintended deployment.
As the ignition is switched on, the pretensioner
controller will directly discharge theenergy capacitors.
When the start up procedure is completed without
detecting any faults, the converter will be activated
allowing the capacitors to be
charged.
The system shall
be fully active within 11 seconds after switching the
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
bedetectedbythemicroprocessor,asoftwareshutdown
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 inopera tive and
failing to discharge the capacitor when instructed
to do so.
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.
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