lock ASTON MARTIN DB7 1997 Repair Manual

The Aston Martin Lagonda Diagnostic System
Installation Instructions ^^?
Removing the CD-ROM (Early Systems) Removing the CD-ROM (Later Systems)

1.
Ensure that your hands are clean before touching
the CD-ROM disc, disc caddy, or the CD-ROM

drive.

2.
Unlock and open the CD-ROM drive door.
3. Press the eject button on the CD-ROM drive (Fig
1
-

25).

4.
After a short delay, the CD caddy will be ejected.
Remove the caddy from the CD drive.
5. Open the caddy and remove the CD. Place the CD
into its storage sleeve and store in the base station
drawer (Fig 8).

1.
Ensure that your hands are clean before touching
the CD-ROM disc, or the CD-ROM drive.

2.
Unlock and open the CD-ROM drive door.
3. Press the eject button on the CD-ROM drive (Fig
1
-

25).

4.
The CD tray will open fully. Remove the CD from
the tray.
5. Gently push on the tray or press the eject button
again to close the motorised tray (Fig 9).
Figure 8. CD-ROM Removal (Early Systems)
Figure 9. CD-ROM Removal (Later Systems)
9-12 May 1996

The Aston Martin Lagonda Diagnostic System
Installation Instructions -=2?
Step 11
Adjust the contrast control. Is the PDU touch screen illuminated?
YES - Co to step 12
NO - Renew the PDU (0017)
Step 12
Observe the display screen. Is the screen displaying a PDU hard error symbol similar to that shown in Fig 17
YES - Note the number and refer to 'Parts Ordering'.
NO - Co to step 13
Figure 17. PDU hard error code
Step 13
Observe the screen display. Is the screen displaying the main menu (Fig 9)?
YES-Co to step 14
NO - Go to step 15
Step 14
Select the PDU system self test option and press the 'tick'
icon.
Does the screen respond?
YES - Co to step 15
NO - Renew the PDU (001 7)
Step 15
Observe the display screen. Is the screen displaying the symbol shown in Fig 18?
YES - Connection problem, go to step 17
NO - Co to step 16
Figure 18. Communications blocked
9-18 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 o: "3^^?
PDU Functions
The PDU main menu provides access into the following functions:
Diagnostics
Training
Digital Multimeter
User Self Test
Diagnostics
On selecting'Diagnostics'from the main
menu,
the user will be prompted to enter the features and market specification
of the vehicle to be tested. Use of the diagnostics in each of the above areas is described later in this guide.
Diagnostics Menu - 95 Model Year
Engine
Anti-Lock Braking System
Vlenu - 97 Model Year
Engine Diagnostics
OBD II Scan Tool
Airbag
Seat Belt Pretensioner
•
•
•
•
Transmission
Engine Datalogger
Climate Control
PATS System
Climate Control
Transmission
Anti-Lock Braking System
Security
Digital Multimeter
The Digital Multimeter function provides the capabilityto measure voltage, current, resistance, frequency, pulse width,
pulse period, and duty cycle. These measurements are usually made using the PDU measurement probes. Measurements
may also be made using the module pin selection function on the Teves Mk
II
braking system and on the Air Conditioning

system.

Training
An on-screen programme is provided to train new users in the use of screen icons and in the use of the digital multi­
meter and datalogger functions.
User Self Test
In order to prove that the equpment is functioning correctly, a complete user self test is incorporated. The user is directed
to test the PDU and then to progressively connect each part of the PDU system which will be tested by the software.
Any fault identified during the test is notified to the user. If no faults are identified, the user is advised on the correct
functioning of the system.
PDU Power
Power for the PDU is supplied via an internal rechargeable battery pack which can keep the PDU operational for
approximately one hour when disconnected from the base station and the vehicle. In order to preserve PDU battery
charge, power to the screen backlight is automatically cut after five minutes of inactivity. The power ON indicator
remains lit, indicating that the PDU is in 'stand-by' mode. One touch of the screen will restore backlight power.
When connected to the base station, power is supplied to the PDU from the Electronic Module to recharge the PDU
battery pack as necessary.
On 95 MY vehicles, the Vehicle Battery Adaptor (VBA) is used to maintain PDU power.
On 97 MY vehicles, when connected via the MPA to either diagnostic socket on the vehicle, power is supplied via pin
4 (chassis ground) and pin 16 (battery power) to maintain PDU power at all times even when the vehicle ignition is
switched off.
On all model years, when connected to the air conditioning system using the VIA, the vehicle battery adaptor (VBA)
must also be used to maintain PDU power.
9-28 September 1996

The Aston Martin Lagonda Diagnostic System
Users Guide D-^?
Vehicle Features
The vehicle features screen illustrated below is used to
identify the vehicle particulars and the model year.
If Airbag - NO is selected, the vehicle is assumed to be 95
model year.
If Airbag - YES is selected, 97 model year is assumed. On
completing entries in the vehicle features screen, the
appropriate vehicle area screen will be displayed.
Vehicle Features
Transmission MANUAL IIBIE^^I
Airbag IDS^I NO
D
Vehicle Area
This screen allows selection of the vehicle system to be

accessed.
Only 4 systems may be accessed on 95 model
year vehicles, on 97 model year cars, 8 systems may be
accessed as follows:
Vehicle Areas
• Engine Diagnostic
• Engine Datalogger
• Transmission
• OBDII Scan Tool
• Climate Control
• Anti-Lock Braking System
• Airbag
. lb Axol
o
PI
mLM
n
WLM
El
Ku^

95 model year software
Zytek Engine Management
GM 4L80-E Transmission Controller
Teves Mk II Anti-Lock Braking System
Valeo Air Conditioning
97 model year software
EEC-V Engine Management
CM 4L80-E Transmission Controller with OBDII
Teves Mk IV Anti-Lock Braking System
Valeo Air Conditioning
PATS Engine Immobiliser
Megamoss security system
FMC Airbag system
Autoliv seatbelt pretensioner
9-30 September 1996

^?
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

The Aston Martin Lagonda Diagnostic System
Users Guide ^=2?
Transmission Diagnostics
Automatic transmission DB7s are fitted with a GM4L80-
E gearbox electronically controlled by a Transmission
Control Unit (TCM)
The TCM is mounted on the rear left wheel
arch.
It may be
electronically accessed from the upper diagnostic socket.
The TCM continuously monitors requests made by the
driver via the gear selector, throttle pedal, mode switch,
etc. This data is used in conjunction with speed input from
the transmission unit to calculate the optimum shift points
undercurrentconditions.Shiftpressureand ignition retard
are also controlled from this data to enhance shift quality
and reduce transmission wear.
TheTCM also detects faults within the transmission system
and stores the relevant fault codes for later analysis.
Gearshifts are controlled by two solenoid valves and a
pressure regulator within the transmission valve block
assembly.
If a serious fault occurs, the TCM removes all electrical
power from these valves and the transmission defaults to
a 'limp home' condition. In this state, only mechanical
selection of either reverse or second gear is available.
Gearshift Timing
Inputs from the performance mode switch (Sport, Normal
or 1st Gear Inhibit) and the throttle position sensor are
used to modify transmission gearshift operation
as
required
by the driver.
Sport mode raises the roadspeed at which gearshifts occur
enabling higher acceleration rates for the vehicle.
1st gear inhibit prevents engagement of first gear to reduce
the risk of wheel slip in icy conditions.
The throttle position sensor signal is continuously
monitored by the TCM to detect a rapid throttle opening.
If the throttle position sensor signal rises rapidly to above
4.5 volts, a 'Kickdown' condition is initiated. In this

condition,
upshifts are delayed to higher road speeds to
provide the higher acceleration required for overtaking
etc.
TCM - PCM Communication
The interface between TCM and PCM allows continuous
exchange of the primary data required to appropriately
control the gearshifts required during driving under
a
wide
range of conditions.
Powertrain
Control
Module
^.. ^
Warm-Up Signal
Throttle Pot Output
Torque Reduction Request
^ •- -^ Transmission
Control
Module
Warm-Up
The Warm-Up signal is sent from the TCM to the PCM and
is used to detect when the transmission reaches normal
operating temperature of approximately 100°C (212"'F).
As this temperature is reached, the modified gearshift
timing required with a cold gearbox may be abandoned in
favour of the standard timing for a warm gearbox.
Throttle Pot Output
The ThrottlePot Output signal is sent from the PCM to the

TCM.
The TCM can then use this information to control
shift timing in relation to the power demanded by the
driver.
Torque Reduction Request
The Torque Reduction Requestsignai
is
sent from the TCM
to the PCM. it is used to temporarily retard the ignition
timing during gear shifts to improve shift quality. When the
gearshift is completed, ignition timing will be returned to

normal.

9-40 September 1996

^?
The Aston Martin Lagonda Diagnostic System
Users Guide
Climate Control Diagnostics
The air conditioning control module is located at the right
end of the air conditioning unit. Since this controller uses
a unique communications protocol, the PDU must be
connected directly to the unit via the Vehicle Inerface
Adaptor as shown in the following cable setup screen.
Cable Setup
Adigitalmicroprocessorwithin the control module receives
data signals from the operator controlled switches.
Comparison of these signals with those returned from
system temperature sensors and feedback devices results
in the appropriate output voltage changes needed to vary:
Blower motor speed, flap position and the solenoids
which respond to operator selected temperature demand.
The air from two blower motors is passed through the
evaporator matrix which, depending on the positions of
the humidity buttons, removes heat from the incoming air.
Dependingon the position of the two blend flaps, the cold
air either passes directly to the vehicle outlet vents, or is
passed through the heater matrix to be reheated and then
to the vehicle outlet vents.
The amount of air passing through the heater matrix is
infinitely variable depending on ambienttemperature and
the temperature selected within the vehicle.
Selecting 'Climate Control' from the vehicle area menu,
will presentthetechnician with the dataloggertool selection

screen.

Details of the signals which may be monitored in the
system may be found in the DB7 Workshop Manual -
Section 8 - Air Conditioning'
Anti-Lock Braking Diagnostics
The Teves Mk IV Braking System consists of two sub­
systems, power braking and anti-lock braking.
The PDU software(DataLogger) only allows the monitoring
of the anti-lock braking system.
The ABS System consists of:
Four wheel speed sensors.
One control module.
Seven solenoid valves.
One pressure switch.
One fluid level switch.
The ABS System
is
controlled and continuously monitored
by the ABS control module, which automatically
switchesoffthesystemifafailure is identified, illuminating
a warning lamp and leaving
full,
boosted braking to all
wheels. A wheel speed sensor is installed at each wheel.
Their wheel speed related signals are processed by the
control module, which triggers the solenoid valves to
modulate hydraulic pressure, preventing the wheels from

locking.
The control module also monitors the fluid
level and will inhibit ABS operation should lowfluid level
be detected.
The Datalogger function will permit monitoring of the
complete system apart from the solenoid valves. The
control module transmits short duration test pulses of 25
to 100 microseconds to the solenoid valves. These
pulses are too fast for the PDU to monitor and as a result
would cause confusing waveforms.
Selecting 'Anti-Lock Braking' from the vehicle area menu,
will present the technician with the following menu of
diagnostic tools screen:
Anti-Lock Brakes Diagnostic
Datalogger
Diagnostic Trouble Codes
o
ABS Diagnostic Trouble Codes
The DTCs which are supported in the Teves Mk IV ABS
system are listed in the workshop manual - Section 5
Brakes Wheels and Tyres.
September 1996 9-43

^^?
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