1997 ASTON MARTIN DB7 belt

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

On
selectingthe
required
vehiclearea,
the selected
software
will be loaded and then the Cable Setup screen will
appear.
Connections will
be
shown directly
to the selected
control
unit
on
95 nnodel year vehicles
using
the vehicle interface
adaptor (VIA) and appropriate cables from the PDU kit.
Select the specified interface devices and cables from the
PDU kit and connect as shown in the diagram.
Cable Setup - 97 MY
On 97 model year
vehicles,
connections
to the
vehicle are
made via the Aston Martin Multi-Protocol Adaptor and
two diagnostic sockets for most vehicle systems.
Cable Setup
Upper Diagnostic Socket
o
Diagnostic Sockets - 97 MY
The diagnostic sockets are located behind the passenger
side underscuttle panel.
Upper Diagnostic Socket
Lower Diagnostic Socket
The
sockets are
mounted on
a
bracket
and
labelled Upper
and Lower. The following lists describe the systems
accessed from each socket.
Upper Diagnostic Socket
Transmission Control Module (TCM)
Megamoss Security System
FMC Airbag System
Teves Mk IV Anti-Lock Braking System
Lower Diagnostic Socket
EEC V Powertrain Control Module (PCM)
PATS Passive Anti-Theft System
Autoliv Seatbelt Pretensioner System
Air Conditioning Diagnostics
The Valeo air-conditioning system uses a unique
communications protocol and therefore the vehicle
interface adaptor (VIA) is required and is connected
directlytotheair-conCPU inordertocarryout diagnostics
work on the system.
September 1996 9-31

The Aston Martin Lagonda Diagnostic System
Users Guide "^7
Establishing Communications
when cable connections are completed, switch on the
vehicle ignition. The electronic control units will 'wake

up'
and communication between the selected control unit
and the PDU will be established.
As communication
is
established with the selected system,
a system menu similar to that below will be displayed.
System Menu Selections
The options for each vehicle system are described in detai
I

on the following pages but menu entries fall into the
following general areas:
Security
• Datalogger
• Diagnostic Trouble Code and
Alarm History Monitor
• RF Transponder Key Learning
• Exit a
o
Datalogger
The Datalogger function is described in detail using a
worked example at the end of this PDU Users Guide.
Diagnostic Trouble Codes
This application enables the PDU to monitor selected
control module trouble codes and provides the following
functions:
• Decode and display any trouble codes logged by
the control module being monitored.
• When supported by the module, decodeand display
enhanced trouble
codes,
together with any count of
the number of occurrences
• Clear all of the trouble codes and freeze frame data
logged in the control module.
• Monitor other data such as the alarm history in this
example.
Note: The 95model year Zytek engine management
system permits clearing of individual trouble codes
selected by the technician on the PDU.
System Specific Tests
These menu entries cover special tests required to program
ortest system specificfeatures. The following are examples
of tests provided:
Engine KOEO and KOER tests
OBDII Readiness test
Output State Control test
Throttle Potentiometer track test
Ignition Key Learn Menu
Remote Transmitter Key Learn Tests
Special Functions Programming
PATS
Security
Exit
Selecting and then confirming the exit option will return
the PDU to the Main Menu.
PDU Use
In the following
pages,
the use of the PDU on each vehicle
system is described.
Engine Diagnostics
Transmission Diagnostics
Climate Control Diagnostics
Anti-Lock Brakes Diagnostics
Passive Anti-Theft (PATS) Diagnostics
Security System Diagnostics
Airbag Diagnostics
Seat Belt Pretensioner Diagnostics
After these system specific descriptions, the following
general purpose functions are described:
Datalogger
Digital Multi-Meter
Diagnostic Trouble Codes
Printing
Training
OBD II Scan Tool
User Self-Test
9-32 September 1996

^^2?
The Aston Martin Lagonda Diagnostic System
Users Guide
Airbag System Diagnostics
WARNING: Whilst it
is
completely safe to
access

and read the airbag diagnostic module memory at
the diagnostic socket, significant personal risks
exist in the performance of any other
tasks
on the
airbag system or components. Therefore all
workshop manual warnings must be read and all
safety procedures must be followed before, during
and on completion of any other practical work on
the airbag system.
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 automatically
deploying airbags in the event of a collision during
forward travel.
Intheeventof
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.

A full description of the airbag system components is
included in the workshop manual.
Airbag Diagnostics
The Airbag Control Module indicates a fault by
transmitting a pulsed signal down the Airbag System
Failure line to flash the SRS/AIRBAC warning lamp.
The fault code is repeated continuously. If there are
two or more faults, the fault code with the highest
priority is transmitted first. The second fault code is
only transmitted when the first fault has been rectified.
TheSRS/AIRBAC warning lamp is also used to indicate
any problem in the seat belt pretensioner system (if
fitted). Flashing of the lamp indicates an airbag fault,
constant illumination of the lamp indicates a seat belt
pretensioner fault.
At the top left of the PDU screen there is a bullet mark
which indicates the current state of the Airbag System
Failure line. As a code is transmitted the bullet mark
can be seen to flash.The PDU reads the fault code, and
writes the code number and fault description to the

screen.
The PDU continues to monitor the transmitted

code.
If the transmitted code changes, the new code
number and description will appear below the first.
PMC Airbag
32 Drivers airbag circuit
shorted or open
o
when remedial action has been taken to correct a
fault, press the Clear Button to clear down the PDU
display. Then use the PDU to ensure that no faults are

reported.

A series of audible beeps, continuously transmitted by
the Airbag Diagnostic Module, indicates that there is
an Airbag System fault to report and that the Airbag
System Failure line
is
open circuit. The PDU is notable
to monitor the fault line in this situation as there is no
pull-up resistor, normally provided by a warning lamp
in the instrument pack.
Rapid continuous flashing of the Instrument Pack
Airbag Failure Lamp indicates that both front impact
sensors are disconnected. No fault code is reported on
the PDU, however on close inspection the bullet mark
can be seen to flicker.
September 1996 9-45

^^?
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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The Aston Martin Lagonda Diagnostic System
Users Guide ^?
Seatbelt Pretensioner Diagnostic Trouble Codes
050A Pretensioner squib leak to battery positive
050B Pretensioner squib leak to ground
050C Pretensioner squib high resistance
050D Pretensioner squib low resistance
0D13 Capacitor voltage error
0D14 Capacitor capacitance
0D09 Energy reserve switch
0D1E Energy shutdown switch
050E Seatbelt pretensioner switch error
0109 Accelerometer function
01OA Acceleration out of range

01
OB Accelerometer offset
0209 Safing sensor error
030A Temperature sensor error
060C Warning lamp short circuit
060D Warning lamp open circuit
060E Warning lamp driver error
OAOC Analogue voltage error
0A09 Communications error
090A EEPROM not programmed
0909 EEPROM checksum
OAOA External watchdog error
OAOB External watchdog time out
020A Safing sensor not closed
090C RAM check error
9-48 September 1996