1997 ASTON MARTIN DB7 engine

^>
Air Conditioning Repair Procedures
Electronic Control Module/Vacuum Solenoid Renewal
8.2.14.1 Electronic Control Module
Renew
8.3.01.1 Vacuum System Solenoid
Renewal

1.
Disconnect the battery earth
lead.

2.
Remove the right hand underscuttle casing.
3. (On left hand cars) Removethe glove box assembly.
3. (On right hand cars) Remove the instrument pack
and surround
trim.

4.
Disconnect the earth wire and three block
connectors from the control module (Fig.
1
-2).
5. Remove the securing screws and module from the
air conditioning unit (Fig. 1-1).
Fitting a new module
is
the reversal of the removal
procedure.
The flaps in the cabin air distribution vents and the
water valve in the pipe line from the engine coolant
system to the heater matrix are all operated by
vacuumactuators.The vacuumfor these issupplied
by four solenoids mounted in a manifold pack
located behind the front left hand footwell outlet.
Failureof a solenoid will require replacement of the
manifold pack.
Procedure

1.
Disconnect the battery earth
lead.

2.
Remove the following:
• glove box and lid
• facia trim (walnut strip)
• radio and ashtray
• centre console switch assembly
• left hand underscuttle casing/knee bolster
Detai
Is
ofthe above operations can be found in the
trim and the electrical sections.

2.
Remove thefixings joining the centre console to the

facia.
This allows the front of the console to be
repositioned for access.
3. Disconnect the ducting from the left hand footwell
outlet.

4.
Remove the two plastic fixings that secure the
slotted footwel
I
outlet and
si
ide the outlet out ofthe
unit.
7. Cut the tie strap holding the vacuum lines and
electrical harness to the underside of the air
conditioning unit.
8. Remove the screws that secure the manifold pack
to the underside of the air conditioning unit and
slide out the plate complete with the manifold
pack.

10.
To fit a new manifold pack reverse the steps for the

removal.

May 1996 8-63

^=2?
Air Conditioning
Portable Diagnostic Unit - Signal Definitions
ThefollowingsignalsaresupportedontheAir-ConditioningControlModule. For each signal. The signal name, mnemonic
and background information are detailed.
Ambient Temperature Sensor
(AMBTEMP)
Auto-Recircuiation Input
(ARECIP)
Auto-Recirculation Output
(ARECOP)
Auxiliary Battery Positive
(AUX+)
Clutch Relay Drive Output
(CLUREL)
A/CCM Pin 34 ref Pin 6
This sensor is located in the right hand blower motor. This signal is used to enable
the A/C system to compensate for changes in ambient air temperature. The output
to pin 34 is 2.732 volts at 0 degrees Celsius and changes by 0.01 volts for each
degree Celsius above or below zero.
A/CCM Pin 9 ref Pin 6
This is effectively an On/Off switch for the A/C system and forms part of the fan
control switch.
Switch Off - Pin 9 should be at ground
Switch On - Pin 9 should be at 10+ volts.
When pin 9 is at ground, pin 3 will be at 10+ volts causing the recirculation flaps
to open.
A/CCM Pin 3 ref Pin 6
This signal will cause the recirculation flaps to close. Operating conditions should

be:

A/C Off - 10+ volts at pin 3, flaps open.
Temp demand minimum - 10+ volts at pin 3, flaps open.
Defrost - 0 volts at pin 3, flaps closed.
Temp demand max - 0 volts at pin 3, flaps closed.
A/CCM Pin 1 ref Vehicle Battery -ve
This signal istheauxiliary supply to the A/CCM. Pin
1
should read battery voltage
if the ignition switch is in the auxiliary or ignition on positions. Pin
1
should read
0 volts when the ignition switch is in the Off position or in position III whilst
cranking the engine. Loss of this supply will cause total failureof the A/C system.
A/CCM Pin 20 ref Pin 6
This signal responds to the input at pin 5 (evaporator sensor). When pin 5 is
between 2.715 and 2.725 volts, pin 20 should read below 1 volt, and the
compressor clutch will be switched off. When pin 5 is between 2.735 and 2.745

volts,
pin 20 will rise to 10+ volts and the compressor will re-engage.
Centre Vent Solenoid
(CVSOL) A/CCM Pin 18 ref Pin 6
The centre vent solenoid controls the operation of the centre vent flap. The centre
vent will open to increase the cooling capabilities of the vehicle when cooling is

selected.
In all other conditions, the centre vent will be closed.
Solenoid energised: pin 18 should read 10+volts and the centre vent will be open.
Solenoid de-energised; pin 18 should read below 0.5 volts and the centre vent
should be closed.
May 1996 8-67

^?
The Aston Martin Lagonda Diagnostic System
Contents
Installation Instructions
Introduaion 9-2
The Aston Martin Diagnostic System 9-2
Diagnostic System Cables 9-5
Base Station Installation 9-8
Problem Solving 9-16
Service Centres 9-21
Service and Maintenance 9-22
Technical Specifications 9-24
Operating Instructions
The Aston Martin Lagonda Diagnostic System 9-27
Software 9-29
Cable Setup 9-31
Diagnostic Sockets - 97 MY 9-31
Establishing Communications 9-32
System Menu Selections 9-32
PDU Use 9-32
Engine Diagnostics - 97 MY 9-33
Transmission Diagnostics 9-40
Climate Control Diagnostics 9-43
Anti-Lock Brakes Diagnostics 9-43
Passive Anti-Theft (PATS) Diagnostics 9-44
Airbag System Diagnostics 9-45
Seat Belt Pretensioner Diagnostics 9-47
Print Facility 9-49
Digital Multimeter 9-50
Diagnostic Trouble Codes 9-53
Datalogger 9-55
Datalogger Example 9-63
Training 9-66
OBD II Scan Tool 9-66
System Self Test 9-69
The Asterisk (*) Menu 9-69
System Setup 9-70
May 1996 9-1

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

^=2?
The Aston Martin Lagonda Diagnostic System
Users Guide
Software
Software for the PDU system is supplied on CD ROM
discs and supports diagnosis on the following control

units:

Zytek Engine Management System (95 MY)
EEC-V Engine Management System (97 MY)
CM 4L80-E Transmission Controller
PATS - Passive Anti Theft System
Teves Mk II ABS System (95 MY)
Teves Mk IV ABS System (97 MY)
Valeo Air Conditioning System
PMC Airbag System
Megamoss Security System
Autoliv Drivers Seat Belt Pretensioner
(where fitted)
All of these systems are supported in English, French,

Italian,
German and Japanese.
In addition to the specific system software listed above,
thePDU isalsoequipped with general purpose software
to provides multimeter, printing and PDU training
options.
Software for 95 and 97 Model Year Vehicles
Software for both the 95 and 97 model year vehicles is

provided.

The PDU system requires a Vehicle Interface Adaptor
(VIA) to communicate with the control units of 95
model year vehicles.
Communication with 97 model year control units is
principally via an Aston Martin multi-protocol adaptor
to 2 inbuilt diagnostic sockets in the vehicle. Only the
air conditioning unit requires the VIA on 97 model year
vehicles.
If the multimeter function is used, the Vehicle Battery
Adaptor (VBA) will be required to provide the basic
supply and ground levels for the multimeter.
Software Loading and Selection
Ensure that the system is powered up and that the PDU is
correctly connected to the base station. Check and if
necessary load the DB7 software CD Revision 002. (see
the installation guide)
Switch 'on' the PDU which will run through two front
screens and then load the following initial PDU software.
Operating System
Main Menu
Selector
Digital Multimeter
Interactive Training
September 1996 9-29

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 "^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

^27
The Aston Martin Lagonda Diagnostic System
Users Guide
Engine Diagnostics - 97 MY
Selecting Engine Diagnostics from the Vehicle Area screen
brings up the following Engine Diagnostics Screen.
Engine Diagnostic
• Diagnostic Trouble Codes
• KOEO on Demand Self Test
• KOER on Demand Self Test
• OBDII Readiness Tests
• Output State Control
• Throttle Checks
• Exit
o
Diagnostic Trouble Codes (DTCs)
On selecting DiagnosticTrouble
Codes,
the PCM memory
will be scanned and any recorded DTCs will be decoded
and displayed.
The engine and transmission DTCs are integral to the On
Board Diagnostics (OBDII) system and are ful ly described
in the DB7 OBD II Diagnostics Manual.
Before attempting to clear the logged DTCs, record all
logged DTCs for use in subsequent fault analysis.
All logged DTCs may be cleared by selecting the EEC-V
EMS DTCs
title.
This will bring up the Clear
(C)
icon which
may be selected and confirmed to clear all logged DTCs.
Note that on clearing all logged DTCs you will also clear
the associated timers, counters and fault history files (and
extinguish the engine management warning lightfor North
American vehicles). The OBD II readines test status will
also clear down and a PI 000 (OBD II readiness test
incomplete) trouble code will be set.. A full drive cycle
(see DB7 OBD II Diagnostics Manual) must be completed
to clear the PI 000 code if required. The PI 000 code will
clear automatically after some miles of driving when all
required tests have satisfactorily completed.
Caution: If a transmission code is logged in the PCM, the
TCM DTCs must be cleared first and then clear the PCM
DTCs. If the PCM DTCs are cleared without clearing the
TCM, the TCM code will immediately reset in the PCM
when power is restored.
Key On Engine Off (KOEO) and Key On Engine
Running (KOER) On Demand Self Tests
Before either the KOEO or KOER test will run, the engine
coolant temperature must be in excess of
BO'C.
Select and
confirm either the KOEO or KOER test. If the coolant
temperature is too low, the Pre Test Engine Warm Up
screen will appear. Start the engine and run until coolant
temperature is at 80+°C.
Pre Test Engine Warm Up
Value : 41°C
80 Engine Coolant Temperature {°C)
Waiting for engine to reach
normal operating temperature
o
KOEO Test
As coolant temperature rises through the BO'C level, the
technician will be requested to turn the ignition off and
then on again. The KOEO test will then commence. Static
inputs to the PCM will be checked and any faults detected
will be recorded and displayed as DTCs. If any DTCs other
than PI 000 are logged, go to the OBD II Diagnostics
Manual and resolve the concern(s) using the OBD 11
diagnostic procedures.
KOER Test
If coolant temperature level is below 80°C, the technician
will be prompted to start and run the engine until coolant
temperature rises above 80°C. As the temperature passes
the 80°C
level,
the KOERtest will commence automatically.
If coolant temperature is above the 80°C level, the
technician wi
11
be requested to start the engine. The KOER
test will commence as the engine is started. Dynamic
inputs to the PCM will be checked and any faults detected
will be recorded and displayed as DTCs. If any DTCs other
than PI 000 are logged, go to the OBD 11 Diagnostics
Manual and resolve the problem(s) using the OBD II
diagnostic procedures.
September 1996 9-33