1997 ASTON MARTIN DB7 filter

The Aston Martin Lagonda Diagnostic System
Installation Instructions 5^27
Battery Charging
The PDU is fitted with internal NICAD batteries
which allow the PDU to be transported whilst
retaining programs. The batteries are not designed
to be used as a general power source. A special
circuit monitorstheamountofcharge in the batteries
so that they cannot be overcharged.
From the time when first operating the system or a
PDU fitted with substitute batteries, it will take up
to 36 hours to achieve full charge. In the meantime,
the PDU can be used whilst connected to the base
station or to the vehicle battery. Keep transit times
to and from the vehicle as short as reasonably
possible to preserve battery charge.
Subsequent battery charges
shou Id
take six to seven
hours from fully discharged. The PDU must always
be left connected to the base station when not in
use in order to keep the batteries fully charged.
CAUTION: The rechargeable NICAD batteries
fitted to the PDU are of a special type and must
only be replaced with GenRad approved parts. Do
not substitute the batteries with any other type.
Always
dispose
of old batteries in compliance with
local recycling regulations. The procedure for
changing the battery pack
is
described later in this
installation guide.
Operating Procedures
Refer to the Aston Martin Diagnostic System Users
Guide for detail on each of the PDU software
options
Selecting Diagnostics

1.
Switch on the PDU, the main menu will be

displayed.

2.
Select 'Run Diagnostic' from the main menu and
confirm the selection by pressing the 'tick'
icon.
A
sequence of menus will be displayed requesting
identification of the vehicle under test.
3. The system will load the appropriate software.

4.
On completion of software loading, disconnect the
PDU from the base station and transfer it in its
carrying case to the vehicle. The additional pockets
in the carrying case may be used for carrying any
interface cables required.
5. If the VIA is required, also transfer it in its carrying
case to the vehicle together with any vehicle
interface cable required.
Using the PDU on the Vehicle
At the vehicle, the PDU may be removed from its
carrying case if required. The PDU should always
be connected to the vehicle using the Vehicle
Battery Adaptor (VBA) (0024). The PDU will
continue to charge from the vehicle battery.
Vehicle Battery Adaptor
This unit transforms battery voltage to the correct
level for the PDU. The VBA (Fig 13) also contains
electrical filters to protect the PDU from any voltage
spikes or other interference from the vehicle which
could affect PDU operation.
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Figure 13. The vehicle battery adaptor
Vehicle Interface Adaptor
When the software requires the Vehicle Interface
Adaptor to be used, it is powered from the vehicle
battery (Fig 14). The Vehicle Battery Adaptor
incorporates a socket into which the VIA to VBA
cable (0028) is inserted. The opposite end of this
cable is inserted into the connector on the VIA

panel.

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Figure 14. The vehicle interface adaptor
9-14 May 1996

^?
The Aston Martin Lagonda Diagnostic System
Installation Instructions

1.
Switch off the PDU and remove all cables.

2.
Remove the cover screw (Fig 23) and remove the cover.
3. If damaged, remove the old foam gasket from the cover and replace with the new one supplied.

4.
Note the orientation of the connector. Disconnect the connector and remove the old battery pack.
5. Fit and connect the new battery pack (Fig 24) with the black cable towards the touch screen.
6. Refit the cover and cover screw.
7. Refer to the Battery Charging instructions for recharging times.
Changing the Dust Filter
The electronic module has a dust filter fitted to the underside of the module. Every three months a new filter wil
be supplied. To change the filter, proceed as follows:

1.
Switch off the mains supply and pull out the old filter (Fig 25).

2.
Feed in the new filter with the blue side facing in, pushing it well into the corners of the holder.
3. Switch on the mains supply.
Figure 25. Dust filter replacement Figure 26. Support arm adjustment
Support Arm Adjustment
Periodically the support arm mechanism may require adjustment.

1.
Remove the cross head arm fixing screw.

2.
Using a suitable screwdriver, turn the tensioning screw (Fig 26) anti-clockwise half a
turn.

3. Refit the leg fixing screw and repeat the operation on the opposite side.

4.
Check that the arm tension is enough to support the weight of the PDU without movement.
VIA Carrying Case
The VIA unit (0018) is secured into its carrying case with two fixing screws from the underside of the case. If a new
VIA is required, remove the two fixing screws and lift the VIA from the carrying case. Return only the VIA for
replacement, do not return the carrying case.
May 1996 9-23

^^?
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.
9-47