1997 ASTON MARTIN DB7 stop start

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.
9-47

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The Aston Martin Lagonda Diagnostic System
Users Guide
Parameter Name
Parameters can be fault codes, inputs to, or specific
outputs from, a vehicle control module.
The number of parameters selectable is limited to 32.
If the number of parameters available for customization
exceeds the d isplay
area,
the arrow buttons wi
11
be present,
allowing display area scrolling.
The parameters declared to Datalogger are initially
presented in alphabetical order.
Record Enabled
Record enabled is used to select which signals are to be

recorded.

To select a signal for recording, touch the rectangle next
to the signal name.
The record button will then be displayed.

Nofe:
Additional rectangles may appear in other columns
beside a selected signal name, indicating that the signal
units may be changed or that the signal may be used
as
a

trigger.

It should be noted that the more parameters you select to
record the slower the PDU's sample rate will be for each
parameter e.g. The PDU may be able to monitor six
parameters sampling each parameter twice a second. If
the number of parameters is increased to twelve then the
PDU would only be able to sample each parameter once
per second, thus reducing its ability to capture fast faults;
therefore it
is
recommended that the number of parameters
is kept to a minimum.
Display Order
Parameters may be displayed on the waveform/ bargraph
screen in any order.
To set the parameter display order, press the required
rectangle to create a numbered list.
Note: It
is
not
necessary to
display all of the parameters
required to be recorded.
This has particular benefits if a parameter is to be used as
a trigger but is not required to be displayed.
Trigger Action
For a detailed description of trigger action, refer to the
Trigger Customisation description on the following page.

S.I.
Units
Certain parameters can be measured / displayed in a
number of different units eg temperature in °C or °F. If a
rectangle appears around the displayed units in the
'S.I.'

column then the units are selectable. Each time the
rectangle is pressed, the selectable units scroll one step
through the available options.
Other Features
To make parameter customization easier two icons have
been introduced on to the bottom of the screen, these are:
This icon simply puts all ofthesignals selected for
recording in alphabetical order irrespective of
the language.
A B C
This icon will put all of the signals selected for
recording at the top of the parameter list in
numerical order.

^T/^

After the parameter customization process is completed,
return to the Datalogger main menu.
Default Customisation
To cancel all customisations, press the
Customisation Reset
icon.
This will reset the
customisation on all parameters to the default

setting.

Trigger Customisation
Datalogger operates using a 'rolling memory'.
When the Record icon is selected on the waveform
display, PDU will start to record data, it will then continue
to record data until its memory is
full.

At this point it will continue recording by overriding the
oldest
data.
This process will continue indefinitely or until
the trigger is activated.
When the trigger is activated it performs a number of
functions.
a) The first function istoplaceazerotimepointwithin
the stored data, this enables the trigger point to be
easily accessible in later stages.
b) The second function is to set a timer, ensuring that
the PDU wil
I
only continue recording for the time
selected in 'test-duration'.
September 1996 9-57

The Aston Martin Lagonda Diagnostic System
Users Guide ^?
Datalogger Timing
Select the 'clock' icon from the main menu screen.
Confirm the selection using the 'tick'
icon.

The Datalogger timing screen should now be displayed.
Datalogger Timing
Signals
Sample Interval
Record time
Pre-trigger
Post-trigger
00:33:20

50%
00:16:40

50%
00:16:40
'^
23]
Datalogger Timing
The Datalogger timing screen allows customisation of the
sample interval and duration of data capture.
The display will identify the number of parameters
(channels) which have been selected to be recorded by
Datalogger.
Timing changes can only be made while data capture is
inactive. Entering Dataloggertiming while vehicle data is
being captured will display the current
settings,
but disable

selection.

Signals
The signals are the number of parameters set for sampIing
by Datalogger.
Sample Interval
The sample interval (frequency) defines the time interval
between successive block requests for all recorded
parameters.
The sample interval is selectable to enable fast response to
intermittent faults.
Note: Very short sample intervals may reduce test
duration
because ttie
PDU memory
becomes
full of
data.

Select the sample interval rectangle.
Acaiculator-style icon should nowbedisplayed. rrr?]
^
Aswellasa calculator-style icon beingdisplayed
there will bea hare
icon,
selecting this icon will
automatically set the fastest sample rate for the
selected parameters.
Note: The fastest sannple rate set using the 'hare' icon may
be too fast for some applications.
Select the calculator-style
icon.

A new screen should now be displayed.
Enter Test Duration
IDD 33 EDI
CL m m [Z]
Ci] ra [I]

1
1 2 1 3 1

0
1
Test Duration
Enter the required value in milliseconds up toa maximum
of 60,000 mS (1 min). At this stage Datalogger will not
verify if the entered sample interval can be achieved.
When Datalogger is actioned to start recording vehicle

data,
and the sample interval is shorter than the fastest
achievable capture time, a warning screen will be

displayed,
requesting changes to the sample interval.
Record Time
The record time (test duration) defines the length of the
data slice which will be preserved for analysis after the
fault occurs. The selected time will be split equally before
and after the fault trigger, e.g. a 10 minutes recording will
preserve data from 5 minutes before to 5 minutes after the
fault.
At the end of the record time the PDU will automatically
stop recording.
The record time is entered in the same way as the sample

interval,
by enabling the rectangle and selecting the
calculator-style
icon.

9-60 September 1996

•
^m:E3^^?
The Aston Martin Lagonda Diagnostic System
Users Guide
Pre-trigger and Post-trigger
The pre-trigger and post-trigger represent the duration of
the tests before and after the trigger point respectively.
Waveform
Select the waveform icon from the main menu, confirm
selection usingthe'tick'icon;thewaveform screen should
now be displayed.
System Icons
For
a
detai led description of each of the system icons, refer
to the on-screen Dataslogger Training Programme.
Datalogger Specific Icons
The Datalogger specific icons are those at the bottom of
the screen.
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TP
OV
149 "C
ECT
-49°C .
149°C •
lAT
-49°C .
_r
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• 1=3
Wa\/eiorm Display
The screen consists of three parts:
• Waveform Display
• System icons
• Datalogger Specific icons
Waveform Display
The waveform display provides a graphical indication of
activity occurring within the displayed parameters. This
feature provides a display of various waveforms
simultaneously. Each waveform represents a vehicle
parameterindicatingmeasuredactivity in relation to time.
The display is dynamically updated atthe frequency of the
sample interval.
Totheright-handsideofthewaveform isadigital read-out
of that signal.
A vertical dotted line (cursor) on the screen represents the
point in time displayed by the digital read-out.
This cursor may be moved by applying finger pressure to
the screen in the position the cursor is required.
The system up or down icons can be used to scroll the
waveform display up or down respectively to look at the
other displayed waveforms.
5V
TP
OV
149 °C'
ECT
-49°C ,
149°C
lAT
-49°C . 1
Os 324s 648s
"^
MMV MMV
MMV
1^
•
Datalogger Icons
Record icon
Press the record icon to start capturing data, a trigger icon
will replace the record
icon.

• d^ •
Press the trigger icon to instigate the manual trigger.
Once the trigger procedure has occurred, a stop icon will
replace the trigger
icon.

Press the stop icon to stop capturing data.
The following icons are to aid viewing / analysis.
September 1996 9-61

The Aston Martin Lagonda Diagnostic System
Users Guide ^2?
Split Cursor Icon
The split cursor icon spl its the vertical cursor into
two parts.
1^

VV

One permanent static cursor represented by
a
solid vertical
line in the waveform display, and one moveable cursor
represented by a dotted vertical line, this is moved by
applying finger pressure to the screen in the position the
cursor is required.
The digital display of the waveforms will now represent
the difference in levels between the two cursors and not
the absolute signal level as detailed earlier.
Re-scale Vertical Icon
Normally all of the waveforms are displayed
with the vertical axis representing the maximum
possible variation ofthesignal,
e.g.
battery voltage
0 to 16 V.
The re-scale icon causes the waveform to scale such that
the recorded variation determines the scale, this normally
enlarges the vertical scale.
The scaling operation can be performed on any of the
displayed waveforms by highlighting the parameter name
prior to the operation.
Once auto-scaling
has
taken place, further manual scaling
may be achieved by using the '+' and '-' system icons.
Waveform Display Number
This icon enables control of the number of
waveforms displayed on the screen at any one
MMV
MMV
time.

Pressing this icon causes the '+' and '-' system icons to
appear. Using these system icons increase or decrease the
number of displayed waveforms.
It should be noted that the more waveforms displayed the
poorer the detail becomes, therefore the number of
displayed waveforms should be kept to a minimum.
Horizontal Scale
-^ This icon performs the same function as the re-
scale vertical icon only for the horizontal axis.
By expanding the scale more detail will be available, thus
proving easier to analyse. However the amount of time
displayed on any one screen will be reduced.
Bargraph / Digital display
Bargraph / Digital display provides another format in
which to display recorded date.
The Datalogger icons operate similar to those used in the
waveform display. However one new icon is provided as
a toggle option from bargraph to digital display.
OV
TP :3.91V
ECT: 57°C 5V
-49°C lAT: 0°C 150°C
-49°C 150°C
II 88 zF 1^
Bargraph / Digital Display
On-Road Trigger
When on-road trigger is selected using the motorway icon
from the main menu a symbol is displayed over the entire
screen display area.
This option is intended for use during on-road tests to
ensure that the PDU screen does not distract the driver.
Press the record icon to start capturing data, a trigger icon
will replace the record
icon.

• iF •
Datalogger Trigger Icon
Press the trigger icon to instigate the manual trigger.
Once the trigger procedure has occurred, a stop icon will
replace the trigger
icon.
Press the stop icon to stop
capturing data.
9-62 September 1996

5'=3^
The Aston Martin Lagonda Diagnostic System
Users Guide
The 'tick' icon was selected to return to the trigger screen
which will then be as shown below.
ABSWL
Trigger
Anti-Lock Bra
^ CTD
AJUJ
^B
6V
.J7.
!•
t 1
•
S.I.

fvl
^ t

]

kes Warning Lamp
Z-.Z4
The Trigger Set-Up Screen
The 'tick' icon was then selected to return to the parameter
customisation
screen.
The screen should now look similar
to that below.
Signals • cn> J^ [Z^ S.L
RLW<133
RRW<133
BAT+P20
BAT+P3
FLS2
FLW<133
•
V
KPH
KPH
V
V
^ Kr-
i c
V
KPH
ini
Parameter Customisation - Final Setup
The 'tick' icon was pressed to access the waveform
display.
The PDU was now ready to start recording data.
The 'record' icon was selected to start recording data.
When the fault occurred, the ABS warning lamp
automatically triggered the PDU. This will place a fixed
cursor on the screen and set the time base to zero. The
PDU will stop recording after the preset record time. If no
record time has been entered, the PDU will use its default
record time of 16minutes and 40 seconds. 8m20s pre-
trigger and 8m20s post trigger.
The following figure indicates the typical waveform display
for the wheel speed sensor fault. The dotted vertical line
represents the trigger point.
16V
ABSWL
OV
240KPH "
RLW<133
OKPH .
240KPH •
RRW<133
OKPH
-55.4s
7.29s
^ 39.6s
^ MMV
\!MV
m

wheel Speed Sensor Display
September 1996 9-65