OBD port ASTON MARTIN DB7 1997 Workshop Manual

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 ^7
TCCS Torque Convertor Clutch Solenoid
The torque converter clutch solenoid is mounted on the
valve body. The signal is Pulse Width Modulated at 32Hz
to provide closed loop control of the pressure across the
converter clutch plates. 1 bit = 0.39% Range 0 to 100%
TP Throttle Position
This is provided by the EECV Engine Management System
as a Pulse Width Modulated signal derived from the
throttle position signal read by that module from the
throttle position sensor.
TCS Torque Convertor Slip
Torque converter slip is defined
as
the difference between
the Input/turbine (ni) speed and the Engine speed (Ne):
Slip = Ne-Ni. The PWM duty cycle may increase from 0
to 100% when TCC is fully applied. In practice a 100%
duty cycle will be achieved only if
a
large slip is detected.
Normal ly only a 50 to 95% duty cycle will be required for
full application of the TCC. Slip is expressed in rpm. 1 Bit
- 1/8 rpm. Range -4096 to +4096 rpm.
TCSW Transmission Control Switch
A three position switch allows the driver to select Sport,
Normal or 1st Gear Inhibit mode. When 'Sport' is selected
gearshifts take place at higher engine revs. When '1st
Gear Inhibit' is selected, the transmission only operates in
the higher forward ratios to prevent wheel slip in icy
conditions.
TISSA Turbine Input Shaft Speed
Turbine speed is the speed of the input shaft of the
transmission measured by the input speed sensor mounted
on the transmission. An alternating waveform is induced
in the sensor by 31 serrations on the forward clutch
housing as it rotates. The waveform frequency and
amplitude is low at low speeds and high at high speeds.
The TCM changes this signal into a digital signal. 1 bit =
1/8 RPM. Range: 0 - 8192 RPM.
TOS+ Transmission Output Speed
The output speed sensor is mounted on the transmission
case and measures the speed of the output shaft. As the
shaft rotates an alternating waveform is induced in the
sensor which varies in frequency and voltage. The wave
form is converted into
a
digital signal by the TCM and used
to control TCC, line pressure, shift timing and torque
management. 1 bit = 1/8 RPM. Range 0-8192 RPM
TRX Transmission Control Switch X
TRY Transmission Control Switch Y
TRZ Transmission Control Switch Z
The transmission range is detected by the pressure switch
manifold (PSM) and input to the
TCM.
The signal consists
of three discrete lines X, Y, Z which transmit a 3 bit binary
code as shown in the table below.
0 = open circuit
1 = short circuit to ground
X Y Z
p
R
N
D
3
2
Error
0
1
0
1
0
0
1
0
0
0
0
1
1
1
0
1
0
0
1
0
1
VS Vehicle Speed
Veh icie speed
is
derived from
a pu Ised
wave form generated
by the speed sensor in the hypoid unit. There are 40 pulses
per shaft rotation and the TCM converts this to vehicle
speed and applies correction for axle ratio and road wheel
diameter. 1 bit -
1
kph. Range 0 - 255kph
Transmission Diagnostic Trouble Codes
The diagnostic trouble codes supported by the CM 4L80-

E
Transmission Control Module are covered indetail inthe
DB7 OBD II Diagnostics Manual.
TOT Transmission Oil Temperature
The transmission temperature sensor signal is used to
control TCC and line
pressure.
It
has a
negative temperature
coefficient so when the temperature is cold its resistance
is high and the TCM sees
a
high voltage. Asthe temperature
warms the volts drop across the sensor decreases and the
signal voltage becomes lower. The TCM converts this
analogue input into a digital signal.
1 bit =
1
°C Range -55°C to +200°C.
9-42 September 1996

The Aston Martin Lagonda Diagnostic System
Users Guide ^=2?
Printer Use Digital Multimeter
Print Trace
The Trace Buffer is used to record technician use of the
PDU.As the diagnostics are executed, the following
information is written to trace:
Screen Title
Menu options selected
Operator questions selected
Operator actions
Control module information
Test limits and results
P codes detected by the DTC monitor
Snapshot data from the datalogger
OBD II freeze frame data
Set up the printer and load with paper. Select Print
Trace and confirm the selection. All recorded
information in the above list will be printed.
Printtrace is supported in English, French, German and

Italian.

Print Screen
The Print Screen function dumps a bitmap image of the
current screen display to the printer. This function is
particularly useful for recordingdata such as waveforms
captured by the datalogger application.
The print screen function is supported in English,

French,
German, Italian and Japanese.
Introduction
The Digital Multi-Meterprovidesthecapability to measure
voltage, current, resistance, frequency, pulse width, pulse
period and duty cycle using measurement probes or
vehicle interface adaptor channels.
WARNING: DMM measurements must not be taken
while the PDU
is
connected to the
base
station. The PDU
measurement system
becomes
referenced to earth when
connected to the base station. Serious measurement
errors may be present
because
of any voltage difference
between vehicle ground and base station earth. Operation
of the PDU in this mode has both functional and safety
implications and therefore must be
avoided.

A digital multimeter (DMM) is resident within the PDU
software toolbox.
The DMM application can be accessed from the main

menu.
On selection of "Digital Multimeter" from the main

menu,
the PDU will always display the same screen,
known as the DMM general screen.
DDD
DMM : Voltage
(+) : RED PROBE
(-) : BLACK PROBE
HOLD/UPDATE Exit
The DMM General Screen
The DMM is used to display measured values, to three
significant figures, in the correct units.
Modes of measurement are Voltage, Voltage (AC),
Resistance, Frequency, Pulse Period, Pulse Width (High/
Low) and Duty Cycle. Current measurements up to 50A
may be made using the current probe. Measurements are
usually madedirectlyusingthe PDU measurement probes.
On the air conditioning system only, when using the VIA,
measurements may be made between specific module

pins.
If required, this mode must be specified when
specifying the measurement to be made.
9-50 September 1996

^7
The Aston Martin Lagonda Diagnostic System
Users Guide
Diagnostic Trouble Codes
Introduction
The 'Diagnostic trouble codes' application enables the
PDU to monitor the trouble codes logged in selected
control module's and provides the following functions:
• Decode and display any trouble codes logged by
the control module(s) being monitored.
• Decode and display enhanced diagnostic
information, together with any count of the number
of occurrences, when supported by the control
module(s).
• Clearsomeorallofallthesetroublecodes selected
by the user on the PDU screen, when supported by
the control module(s).
Diagnostic Trouble Codes are logged by the Engine
Management and by the Automatic Transmission control
units and can be accessed using the PDU. Logged codes
in the 95 MY Teves Mk II ABS controller can only be
accessed using the brake warning light. The Air
Conditioning control unit does not log trouble codes.
Operation
From the Main Menu make the following selections:
Select Diagnostics
Select Engine or Transmission
The system will then load the appropriate
software
Select Diagnostic Trouble Codes
Connect the PDU to the car as shown on the
screen diagram
Select the / icon to confirm connection
The PDU will then interrogate the chosen control
unit and will display any logged trouble codes.
If no trouble codes have been flagged by the control
module, the PDU will display a screen similar to Fig. 15
The trouble code screen will be headed by a module title
block followed by a list showing all logged trouble codes
for the seleaed module.
Note: There may be more logged diagnostic trouble
codes than displayed on the first
screen.
Use the 'up
arrow' and 'down arrow' icons if
necessary
to scroll
through the total display.
On the Zytek engine management system only, each
trouble code definition will be individually selectable to
invoke the clear trouble codes screen. If one or more
trouble codes are selected, the clear all and clear selected
trouble code icons will be displayed.
On all other systems, only the 'Clear All' function is
available.
'Clear All' and 'Clear Selected Codes' Icons
Freeze Frame Data
m*
As any engine management trouble code is

logged,
the system takes a snapshot (freeze
frame) and records the state of all signals at
that time.
On the Zytek engine management system (95 MY), freeze
frame data can be displayed by selecting a logged trouble
code and touching the 'snowflake'
icon.

On the 97 MY EEC V engine management system, freeze
frame data is accessed using the OBD II scan
tool.

ECC-V EMS DTC'S
No fault codes present
l^
D
a
El
The No Fault Codes screen
September 1996 9-53

The Aston Martin Lagonda Diagnostic System
Users Guide =2?
Training
The training programme incorporated into the PDU
software is designed to cover the needs of new users and
those who have basic PDU skills but require further
training on the DMM and Datalogger functions.
Select 'Training' from the PDU main menu to bring up the
training menu.
New User Training
The new user training program takes the student through
a structured sequence of activities to learn the meaning
and use of the basic screen icons. The traineemay then
work through programmed exercises to learn the digital
multi-meter and then the datalogger functions.
Existing User Training Menu
in this program the existing user may select training from
the following list:
• User Screen Controls
• Digital Multi-Meter
• Datalogger
OBD II Scan Tool (Not 95 MY)
The OBD II Scan Tool is designed to access the memories
of the engine and transmission control units to monitor
and extract data relative to emissions control.
The following types of data may be accessed:
Current Powertrain Data
Monitor Freeze Frame Data
Request Trouble Codes
Clear Trouble Codes
Request Oxygen Sensor Test Results
Monitor Oxygen Sensors
Display Pending Trouble Codes
Request On-Board Monitoring Test Results
Examine Readiness Tests
Malfunction Lamp Status
The data to be monitored is selected from the OBD
11
main

menu.

For example if Monitor Freeze Frame Data is selected, the
system will display up to 11 parameters which are always
recorded when a fault code is logged. The parameters are
as follows:
0 : SUPP Supported
2 : FCFF Fault Causing Freeze Frame
3 : FSS Fuel System Status
4 : CLV Calculated Load Value
5 : ECT Engine Coolant Temperature
6 : STFT-B1 Short Term Fuel Trim - bank 1 (Cyl
1
-3)
7 : LTFT-B1 Long Term Fuel Trim - bank
1
(Cyl 1-3)
8 : STFT-B2 Short Term Fuel Trim - bank 2 (Cyl 4-6)
9 : LTFT-B2 Long Term Fuel Trim - bank 2 (Cyl 4-6)
12:RPM .Engine Speed
13:VS Vehicle Speed
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in:s3''^

The Aston Martin Lagonda Diagnostic System
Users Guide
#
Accessing Freeze Frame Data
The freeze frame data is vital in analysing unresolved
trouble codes. If an emissions related trouble code occurs,
complete a diagnostic trouble code report form including
the vehicle data, logged trouble codes and the freeze
frame data. Fax a copy of the form to Aston Martin Service
Operations Department who will assist in resolving the

concern.

To access freeze frame data, proceed as follows:

1.
Switch on the PDU and select 'Engine Diagnostics.

2.
Select 'OBD II Scan
Tool'.
The scan tool software
will load and the 'Cable Setup' screen will appear.
3. Connect the PDU to the lower diagnostic socket
using the multi protocol adaptor (MPA). Svvitch on
the ignition. After communications are established,
the OBD
11
Main Menu will appear.
OBD
11
Main Menu
• Monitor current powertrain
data
D
• Request emission trouble codes 1 ^^ 1
• Monitor freeze frame data
' Clear emission trouble codes
• Doniiact nw\/rtan concry
O

4.
Select 'Request Emission TroubleCodes' and press
the 'tick'
icon.
, ., - . i-
Diagnostic Trouble Codes
0:P1243
o
5. Any logged diagnostic trouble codes will be
displayed on the screen (e.g. 0:P1243). Record
both the list number
(e.g.
0,1,2, etc) and the logged

'P'
codes (e.g. PI 243, etc).
6. Press the 'tick' icon and return to the OBD II main

menu.

OBD II Main Menu
• Monitor current powertrain
data
• Request emission trouble codes
• Monitor freeze frame data
• Clear emission trouble codes
• Doniioct nvx/nort cancnr
D
D
O
7. Select 'Monitor Freeze Frame Data' and press the
'tick'
icon.

8. The numeric keypad screen will appear. Enter the
list number noted in step 5 for the fault code to be
investigated and press the 'tick'
icon.

Freeze frame
^^HHI
CL m [XI s
ci] s m

1
1 1 2 1 1 3 1

0
1
9. The 'Select PIDS to Monitor' screen will appear.
Select FO PIDs to Monitor
0 : SUPP 2 : FCFF
3: FSS 4:CLV
5 : ECT 6 : STFT-B1
7 : LTFT-B1 8 : STFT-B2
9 : LTFT-B2 12 : RPM
13 : VS
WWWM
o
September 1996 9-67