fuel ASTON MARTIN DB7 1997 User Guide

Electrics
Component Index Sheet 3 - 97
MY

Component
Name
Interior Light - Rear RH
Key Solenoid
Key-In Warning Switch
Low Coolant Signal Transmitter
Low Level Sensor (Screenwash)
Map Reading Light
Mass Airflow (MAF) Sensor
Multifunction Module
Number Plate Lamp - LH
Number Plate Lamp - RH
Oil Pressure Transducer (EOP)
PATS Module
PATS Transceiver
Performance Mode Switch
Powertrain Control Module (PCM)
Purge Cannister Vent Valve
Radiator Switch
Radio
Radio Aerial
Radio Telephone Connector
Radio Tweeter (LH)
Radio Tweeter (RH)
Rear Lamp - LH
Rear Lamp - RH
Relay - Air Conditioning
Relay - Air Conditioning W.O.T.
Relay - Air Pump
Relay - Auxiliary Load (
Relay - Auxiliary Load (
Relay - Courtesy Lights (
Relay - Clutch (
Relay-Day Time Running (
Relay - Drivers Seat Heater (
Relay - Fan Change-Over (
Relay - Fan Run On
Relay - Front Fog Lamps
Relay - Fuel Pump 1
Relay - Fuel Pump 2
Relay - Gearbox Failure Warning
Relay - Glass Drop
Relay - Hazard Unit
Relay - Headlamp Dipped Beam
Relay- Headlamps
Relay - Heated Front Screen Control
Relay - Heated Rear Window
Relay - Hood Down (Roof Down)
Relay - Hood Up (Roof Up)
Relay - Horn
Relay - indicator Unit (Flasher Unit)
Relay - Left Quarter Light Up
Relay - Left Quarter Light Down
Relay - Load
Relay- Main
Relay - Main Beam
Relay - Passenger Seat Heater
Component
Location
14-6
14-4
14-4
7-13
14-3
10-9
14-1
6-1
14-8
14-7
15-3
4-9
15-4
6-8
4-1
15-7
15-2
5-1
5-4
8-3
5-2
5-2
15-8
15-6
see relay location chart) di II II II
II II II II
II II II II
11 II II II
II II II II
II II II II
II II II II
II II II II
II II II II
11 II II II
II II II II
II II II II
II II It II
II II II II
11 II II II
II II II II
II II II II
II II II II
II II II II
II It II II
II II II II
11 II II II
II II II II
11 II II II
11 II II II
II II II II
II II II II
II II II II
II II II II
II II II II
Circuit
Reference
16-A2
9-D3
9-D3
12-82
3-A2
8-A4
5-D2
12-B5
16-D6
16-C6
5-C4
12-B1
9-C2
4-A2
6-B5
15-B3
5-D1
10-B3
16-C2
16-B5
8-A3
12-C2
15-B6
16-D2
3-A4
3-A5
1-A5
9-D1
12-D1
9-D1
1-B5
1-A6
23-D3
3-C4
3-A3
) 1-B5
) 17-A2
) 17-A4
9-D2
) 12-C1
) 8-C3
2-A2
) 2-B2
) 12-D3
) 8-C4
) 19-A2
) 19-A3
) 1-85
) 8-C3
) 18-A5
) 18-A5
) 12-D1
) 12-D2
) 2-83
) 24-D3
September 1996 6-45

Electrics

Relay Location Index - 97 MY
D^^
Facia Component Panel
- LHD
Passenger
Function
Heated Front Screen Timer Relay
Multi-Function Module
Low Coolant Transmitter Module
Main Relay (Red Stripe)
Auxiliary Load
Auxiliary Load
Fusebox
Heated Front Screen Fuse
Otter Switch (door drop glass)
Side
-
Right
to
Left
Base Colour
Yellow
Black
Black
Red
White
Black
Black
White
Fascia Component Panel
- LHD
Drivers Side
-
Right
to
Left
Function
Gearbox Failure Warning
Ignition Load
Courtesy Lights
Indicator/Flasher Unit
Hazard Warning
Heated Rear Window
Rear
Fog
Light
Dimmer Module
Fusebox
Base Colour
Black
White
Red
Yellow
Green
Blue
Brown
Black
Relay/Module Cover.
Grey
Black
Black
Silver
Blue
Blue
Orange Fuse
Black
Relay/Module Cover.
Pink
Blue
Blue
Black
Black
Blue
Blue
Red
Location
1
2
3
4
5
6
7
8
9
Location
1
2
3
4
5
6
7
8
9

Seat Heater Relays - Beneath the Driver and Passenger Seats
Boot (Trunk) Relays Volante (Front To Rear)

Function
LH Quarter
Up

LH Quarter Down
Hood Down
Hood
Up

RH Quarter Down
Reverse Lights
Fuel Pump
1

Fuel Pump
2

Tilt Sensor
RH Quarter
Up

Stop Lights
Hood Lift Fuse
Fusebox
Hood (Roof) Control Module
Thermal Cut-Outs Quarter Glasses
Base Colour
White
Yellow
Blue
Green
Red
Yellow
Blue
Green
White
Black
Brown
Black
Relay/Module Cover.
Pink
Pink
Pink
Pink
Pink
Blue
Silver (Bosch)
Silver (Bosch)
Pink
Pink
Blue
Green
30A

Black
Location
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

Boot (Trunk) Relays Coupe (Front To Rear)
Function
Stop Lights
Reverse Lights
Fuel Pump 1
Fuel Pump 2
Tilt Sensor
Fusebox
Base Colour
Brown
Yellow
Blue
Green
White
6-66

Relay/Module
Blue
Blue
Silver (Bosch)
Silver (Bosch)
Pink
Cover. Location
1
2
3
4
5
6
September
1996

NO
COLOUR
PIN
AREA I0S8
KB I
I7.B3-I79 JAO
OC 2 H.BI

WINDOW LIFT NO COLOUR
PIN
AREA I0S3
GR I
I6.A3 1051
GW 2
I6.A3
I
NO
COLOUR AREA 1829
RN
I4.BI
I HEATED BACKLIGHTi
VAPOUR MANAGEMENT VALVE
HOOD LIFT NO COLOUR 1054
GW
1053
GR

1060 GW lOEl
GR

1

I
4

I

AREA I6.AI le.AI
I5.ei-I54A I5.BI-I54B
NO COLOUR
PIN

1096 BW 828
BG

AREA I4.AI I4.BI
I4.B5-I60 I4.BI
FUEL PUMP
I
NO COLOUR
PIN
1086
B 1
1087 UG
2

AREA I6.B3 I7.A2
NO COLOUR
PIN
AREA 16.85 I7.A3
INTERIOR LIGHT NO COLOUR
PIN
AREA
1056 P I I4.C4-I56 1057 PW 2 I4.C4-I57
m

fsD
1ST SECURITY STEM
I
AERIAL
I
NO
COLOUR
PIN
799
BR I
1800
B 2

AREA 14.Al 14.Al
I
NO
COLOUR ||055
TIN
AREA I7.B6
LINK PINS
I a 2
LING
PIN 3 a 4

NO COLOUR
PIN
AREA
1062
NP
792
VG
I6.B3-I68 I4.AI
6)[5]o[4)|3J
02 01 Qi 03
REAR LAMP
SHORTING
PLUG

02 01 Ql 03

NO COLOUR PINAREA
1064
GP I
IG.B5-I74
1065 GP
2 16.01 1066 RU 3 I4.C5-I59
1067
RU 4 16,01
Ql D3 D2 01

LINK PINS
I 8 4

RH REAR LAMP
NO COLOUR 1067
RU
1068
ON
1069 CW 1070
B
1071
RG
1065
GP
PIN 1 ? ^ 4 •) 6

AREA 16.01 I6.B3-I7I I6.BI-I67 I6.C3-IG9 I6.C3-I70 16.01

mmra CEIinnn
(—\ Qi 01
cr
D 0 I—I 03 06 SHEET 18 '• AREA B/CI

0


01 Qi 0 D 03 06

NO COLOUR AREA 813
LGO 14.01
1080
B
I6.B4-I73 FUEL TANK SENDER UNIT
NO COLOUR AREA 1086
B
1088
B
1090
B
1091
B

I6.A5 I6.A6 16.84-173 I6.C3-I69

TH^
SHEET 17 AREA Bl
-» ^

-F^Pl-'
NO COLOUR
PIN
AREA
1094
BR U
16.86-178
1095 BR W 16.84-172
NO COLOUR PIN 797 S I
1092
B 2
652
WU 3
1093
HP 4

AREA 14.01
I6.B4-I73 14.01 I6.B5-I75

NO COLOUR AREA 2183
B
I6.C5-2I8 1084 RG
16.04

RADIO TELEPHONE

E

Di 05 D 0 D D 04 08/

4
8
J^Q a
£o 0 PO 0
T?D 0 ^ 1 S ^
NO COLOUR
PIN
1081
BR I
1082 PG
2
3
NO COLOUR AREA
1078
NP
I6.B3-I68 1079
BR
I6.B4-I72
AREA I6.B4-I72 I7.C6
1084
RG 1085 B 16.03-170 I6.B4-I73

NO COLOUR
PIN
1081
BR I
1082
PG 2
3 i
RS 4
5 6 1084 RG
7
1085
B 8

AREA le.CG 16.CG

I6.C6 I6.C5-2I8

Zl
1
RH NUMBER PLATE LAMP
NO COLOUR
PIN
AREA 1081
BR I
I6.C4 2184
B 2
l6.C5-2ia
BOOT LOCK ACTUATOR NO COLOUR
PIN
AREA 2185
B I
I6.C5-2I8 1082
PG 2
I6.C4

^[}
[}

JLH
NUMBER
PLATE LAMP
NO COLOUR AREA 2186
B
I6.C5-2I6 ;I083
RS
I6.D4

Wiring Diagram
Model - Aston Martin DB7
Harness Title - Rearward - 3
Part No. -
B3
7-84641

Revision - 0 Sheet 16 of 26-97 MY

STOP LAMP
NO COLOUR 807
CB
1097
G
1098
GP

1099
G

RELAY
PIN AREA 85 I4.CI 86 I7.D2 87 I6.B5-I74
87A
30
17X2

REVERSE LAMP RELAY FUEL PUMP RELAY 1

NO COLOUR 803
SLG
1100
W
IIOI
GN

1102
NP
PIN 85 88
8/
R7A 30
AREA M.CI 17.02 I6.B3-I7I
I6B5-I75
NO COLOUfl 335 OR 1103 KB 1087 UG 337 RN 1104 NP
PIN BS R6 87 R7A 30
AREA I4.CI I7.B3-I79 I6.A5 14.01 17.02
FUEL PUMP RELAY 2
NO COLOUR 336 0 1105 KB 1089 UR 809 YN 1106 NP
PIN AREA 85 I4.CI 86 I7.B3-I79 87 le.AG 87A I4.CI 30 I7.C2
TILT SENSOR RELAY
NO COLOUfl 1109 B 1110 WK
nil BO 1112 B
PIN AREA 85 17.84-183 S6 I7.B4-I82 87 87A I4.B4-I58 30 I7.B4-I83

I^OBROWN
BASE
87A ^JSSPBL

[jylYELLOW
BASE

ma

3«-i

J¥tU

SHEET
16
AREA
B6

10 in

'-fts'^B^-'

lijZ-il
[NATURAL
BASE

L 3JA
NO COLOUR AREA 1107
N
17.83-180 llOe
N
17.83-181
NO COLOUR 1125
N
1126
G
1127
G
1128
N
1130
N
1072
R
1075
R
1133
G
1135
N
1137
G
1138
N
1140
N
PIN 1 2 3 4 5 6
/
8 9 10 II
12 13
AREA 17.83-180 16.86-177 16.86-177 I7.B3-I8I I7.B3-I80 14.84-155 14.84-155 16.86-177 17.83-180 I6.B6-I77 I7.B3-I8I I7.B3-I8I
c

SHEET
25
AREA
B/C6

CZE
BOOT FUSEBOX HARNESS
•^-
rp
NO COLOUR
iioe NP 1099 G 1097 G 1129 NP 1115 NS 1131 RS 1132 RG 1134 m 1136 NS 1100 W 1139 NP 1104 NP
PIN 1 2 3 4 5 6 7 8 9 10 II

\l
AREA I7.A3 I7.AI I7.AI 16.83-168 I7.C4 I6.B5-I76 I6.C3-I70 17.84-182 I7.B5-I84 I7.A2 16.85-175 I7.A2

I

D
a
D
D
D
D,
D
c^
D
D
D
0
D
D

NO COLOUR
PIN
1113
VS A
1114
NS B

AREA 17.86 I7.C6

i'^AAA'

ITYRE
COMPRESSORI
NO COLOUR AREA 1115
NS
I7.DI 1116
8 I7.B4-IB3
5^

\_/
SECURITY NO COLOUR 1055
TIN
1026
KB
1117
BR
1118
BR
1028
HI
772
OR
1027
U

1119
WY
3
YS
1113
YS
1120
GR
1121
8
1122
8RD

1021
UO
773
OU

374
0

1
LG
1082
PG
1123
GW
1114
NS
1124
NS

SYSTEM
PIN 1 ? 3 4 5 6
7 8 9 10
II II 12 13
14 15
16
17 18 19 20 ?l
22 23 24 25 2b

AREA I6.C2 I4.B6 16.84-172 16.86-178 14 .C6 I4.CI 14.06
17.84-182 M.BI I7.B5 I5.B1-163 17.84-183 I6.82-I67A
I4.C4 I4.CI
I5.BI
I4.CI ie.C4 16.81-167 17.85 17.85-184
'^7
Wiring Diagram

Model
- Aston Martin DB7

Harness
Title - Rearward - 4

Part
No. - B37-84642

Revision
- 0
Sheet
17 of 26-97 MY

The Aston Martin Lagonda Diagnostic System
Users Guide ^-^z?
OBD
II
Readiness Test Monitor
- 97 MY

SelectingOBD II Readiness
Tests
will bring up the following

screen.

OBDII Readiness Tests
1
of 9
tests completed.
Logged DTCs
: 1

The following tests have been
identified
as
incomplete:
MISFIRE
ir
1 C.C.M.

CAT MON 1IPURGE
MONII SAIR
M"ONn

02 SENS
1l02
HEAT
II EGR
MONTI

@
This software monitors
the
status
of all
significant
components and parameters required
to
control vehicle
emissions. When the tests are satisfactorily completed, the
test boxes wi
11
be empty and the PI 000 status code wi
11
be

removed from
the DTC
list.
If any problem
is
detected,
the tests will be terminated and
the status will be shown as
on
the screen above e.g.:
1 of

9 tests completed. Logged DTCs
: 1

Incomplete test titles will remain
in the
screen boxes.
Completed test titles are deleted from
the
screen boxes.
Details
of any
trouble codes
may be
accessed using
the

Diagnostic Trouble Code function.
The tests incorporated into this routine are as follows:
Misfire Monitoring
Fuel System Monitoring
Comprehensive Component Monitoring
Catalyst Monitoring
Purge System Monitor
Secondary
Air
Injection Monitor
Oxygen Sensor Monitor
Oxygen Sensor Heater Monitor
Exhaust Gas Recirculation Monitor
Throttle Position Sensor Track Test
- 97 MY

This test
is
used
to
detect
any
problems with
the
throttle
potentiometer track which could cause faulty throttle
position signals
to
enter
the
PCM. Such signals would
result
in
incorrect calculation
of
engine power demand
and possibly create excessive fuelling and high emissions.
Selecting Throttle Checks from
the
Engine Diagnostics
screen will bring uptheThrottle Position Sensor Track Test

screen:

Throttle
pot
track test
Throttle State: PART
Value
: 1.9V

ov
Throttle
pot
voltage
Depress
The
Throttle Slowly
5V

o

Follow the screen instructions
to
test the throttle position
sensor track. The throttle must be moved slowly from fu
I
ly
closed
to
fully open without hesitation.
Any
pause
in

throttle movement will
be
interpreted
as a
track fault.
If
a
fault
is
detected, repeat
the
test several times
to

elliminate hesitant throttle movement errors from actual
potentiometer faults.
If
a repeatable fault
is
detected,
the

potentiometer must
be
replaced.
9-34 September
1996

^^2?
The Aston Martin Lagonda Diagnostic System
Users Guide
Output State Control - 97 MY
This menu item provides a quick test of the basic electro­
mechanical components controlled by the PCM. These
tests should be performed in a key on engine off state.
The selections available are:
• Low Speed Cooling Fans
• High Speed Cooling Fans
• Set Electromechanical Outputs
Low and High Speed Fans
Selecting and confirming either the low or high speed
cooling fans will run the fans at the selected speed for 5
seconds to verify their operation.
Electromechanical Outputs
This selection will cause the following electromechanical
devices to operate for five seconds
Air Pump
Fuel Pumps
Canister Purge Valve
Idle Air Control Valve
Observing each device in turn as the PCM outputs are
turned 'On' will enable the technician to verify correct

operation.

September 1996 9-35

The Aston Martin Lagonda Diagnostic System
Users Guide ffi:S5'=2?
Engine Datalogger
The datalogger software is designed to aid the technician in identifying permanent or intermittent faults in the DB7's
electrical and electronic systems. It can provide a recorded view of selected signals over a chosen time period. This
recording may be captured in a static, rolling road or road test situation. Data recorded during such tests may then be
analysed on completion of the test or printed out for later analysis.
Datalogger operation is described using a fully worked example at the end of this PDU Users Guide.
The full list of datalogger signal names and descriptions is provided in the DB7 OBDII Diagnostic Manual and on the PDU

screen.
The following list is a summary of the PCM signals which may be monitored.
Signal Description
ACCS Air-Con Control Switch - 1 = A/C On
ACP Air-Con Pressure Sensor - 1 = A/C pressure high
ACT MAX Maximum Intake Air Temperature signal during normal running
Adap Fuel 1 Current Adaptive Fuel Correction - (% of range)
Adap Fuel 2 Current Adaptive Fuel Correction - (% of range)
ADPT1F Adaptive Fuel - Table 1 failure mode
ADPT2F Adaptive Fuel - Table 2 failure mode
AIR Air Pump On/Off - 1 = Pump On
AIRM Air Pump Monitor -1 =
high,
pump on
B+ Battery Positive - Volts
BARO Barometric Pressure
CID Cylinder Identification - Cam sensor status
CMP STAT Cam Position Sensor -1 = CID mis, not currently reliable
DRVCNT Number of OBDll Drive Cycles Completed
DSDRPM Desired engine speed (RPM)
DTCCNT Diagnostic Trouiale Codes Count (Fault codes + pending codes. MIL and non-MIL)
ECT MAX Maximum Engine Coolant Temperature signal during normal running
ECT STAT Engine Coolant Temperature - in or out of range
ECT-C Engine Coolant Temperature - "C or raw counts
ECT-V Engine Coolant Temperature - Volts or raw counts
EGR STAT EVP EGR sensor failure
ENGLOAD Engine Load (Ratio of air charge over standard)
ENGRPM Engine Speed - RPM
EPT DPFE Sensor feedback
EVAP DC Cannister Purge Duty Cycle (% on)
EVAPCVA Vapour Management Valve (VMV) fault detected
Evts HI Cumulative cylinder events total carried over from previous background logic executions
Evts LO Cumulative cylinder events total carried over from previous background logic executions
FPM Fuel Pump Monitor - 0 = pump off, 1 = pump on
FPUMP DC Desired Fuel Pump Duty Cycle - 0% or 100%
H02S12 Sensor Output - Volts
H02S21 Sensor Output - Volts
H02S22 Sensor Output - Volts
H02S1I Sensor Output - Volts
HFC High Speed Fan Status
Htrl
1
ret Highest number of retries seen on the H02S 11 heater
Htrl 2 ret Highest number of retries seen on the H02S 12 heater
Htr21 ret Highest number of retries seen on the H02S 21 heater
Htr22 ret Highest number of retries seen on the H02S 22 heater
HTRCM11 H02S n heater current
HTRCM12 H02S 12 heater current
HTRCM21 H02S 21 heater current
HTRCM22 H02S 22 heater current
9-36 September 1996

^
The Aston Martin Lagonda Diagnostic System
Users Guide
Signal Description
lACDTCY Idle Air Control Duty Cycle (% open)
lAT Intake Air Temperature - °C or raw input counts
lAT STAT Air Temperature - Temperature sensor failure
lAT-V Intake Air Temperature - Volts or raw counts
IGN Desired Ignition Timing - ° BTDC
INDS Input from manual lever position sensor (counts)
IPWA Injector Pulse Width in mS- Bank A (Cylinders
1
-3)
IPWB Injector Pulse Width in mS- Bank B (Cylinders 4-6)
LAMSE1 Current Short Term Fuel Trim 1, adjustment from stoich - (% of range)
LAMSE2 Current Short Term Fuel Trim 2, adjustment from stoich - (% of range)
LFC Low Speed Fan Status
LOOP Fuel Control -1 = Open Loop, 0 = Closed Loop
MAF MAX Maximum Mass Air Flow signal during normal running
MAF Raw MAF sensor output (A/D counts)
MAF STAT Mass Air Flow Meter - MAF sensor failure
MIL Mali Indicator Lamp Status -1 = Lamp On
Mis HI Cumulative misfires detected by misfire test (Hi bit).
Mis LO Cumulative misfires detected by misfire test (Lo bit).
Mis nc HI Cumulative misfires detected by a misfire test (Hi bit).
Mis nc LO Cumulative misfires detected by a misfire test.
Misi HI Cumulative misfires detected by cylinder
1
misfire test (Hi bit).
Misi LO Cumulative misfires detected by cylinder
1
misfire test (Lo bit).
Mis2 HI Cumulative misfires detected by cylinder 2 misfire test (Hi bit).
Mis2 LO Cumulative misfires detected by cylinder 2 misfire test (Lo bit).
Mis3 HI Cumulative misfires detected by cylinder 3 misfire test (Hi bit).
Mis3 LO Cumulative misfires detected by cylinder 3 misfire test (Lo bit).
Mis4 HI Cumulative misfires detected by cylinder 4 misfire test (Hi bit).
Mis4 LO Cumulative misfires detected by cylinder 4 misfire test (Lo bit).
Mis5 HI Cumulative misfires detected by cylinder 5 misfire test (Hi bit).
Mis5 LO Cumulative misfires detected by cylinder 5 misfire test (Lo bit).
Mis6 HI Cumulative misfires detected by cylinder 6 misfire test (Hi bit).
Mis6 LO Cumulative misfires detected by cylinder 6 misfire test (Lo bit).
MISF Misfire Monitor - 1 = Currently misfiring
ODCODES Total number of on-demand codes currently stored.
PGM CVS DC Purge Management Duty Cycle (% on)
PIP Profile ignition Pick-Up - PIP input level
PNP Park Neutral Position Switch
R-BIAS1 Rear bias trim (Bank 1, cylinders
1
-3)
R-BIAS2 Rear bias trim (Bank 2, cylinders 4-6)
RATCH Lowest TP reading during driving
TP MAX Maximum Throttle Potentiometer signal during normal running
TP STAT Throttle Position Sensor - TP sensor failure
TP Throttle Potentiometer - Volts or counts
TPR-V Raw counts from sensor
TQ-NET Net torque into the torque convertor
TRIP OBDII Drive Cycle Complete (except cat monitor) - 1 = Trip completed
TRIPCNT Number of Completed OBDII Trips
VS MAX Maximum Vehicle Speed signal during normal running
VS STAT Vehicle Speed Sensor mode flag
VS Vehicle Speed - MPH
WAC Wide Open Throttle A/C Cut-Off -1 = High (WOT Relay)
September 1996 9-37

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

Two adjustments
may
beset with the aid of the PDU
on 95

MY vehicles.
• Throttle Potentiometer
• Idle Fuelling Trim
From
the 95 MY
Main Menu, make
and
confirm
the

following sequence
of
selections:
Diagnostics
/

Manual
or
Auto Transmission
/

Engine
/

Engine Setup
/

The following connection diagram will then be displayed.
Throttle Sensor Adjustment
- 95 MY

Note:
The
throttle stop
and
throttle cable adjustments
must
be
correct before setting
the
throttle potentiometer.
On completion
of the
engine setup connections
the
test
selection screen will
be
displayed.

1.
Select Throttle Potentiometer.

2.
Turn
the
ignition switch
to
position
II but do not

start
the
engine.
3. Monitorthethrottle potentiometer bargraph voltage
at fully closed
and
then
at
fully open throttle.

4.
The
throttle potentiometer voltage specifications

are:

Throttle Closed
0.57 -
0.59V

Throttle Full Open
4.00 +V

Cable Setup
Diagnostic Socket D
Engine Setup Connections
Tinrottle Position Sensor
Value
:
0.43V

570
600

Idle Voltage
(mV)
Make adjustments as
necessary

Throttle Potentiometer Voltage
5.
If
both voltages
are
either high
or low,
loosen
the

two throttle pot screws and adjust the potentiometer
until
the
specified voltages
are
achieved. Carefully
tighten both screws ensuringthat the potentiometer
does
not
move during tightening.
6.
If
either voltage
is
unstable
or if the
specified
voltages cannot
be
achieved, investigate the cause.
If
the
potentiometer
is
replaced,
set the new pot

using steps
3-5
above.
Note:
On
automatic vehicles,
the
kickdown switch
adjustment check follows the throttle
pot
adjustment.
9-38 September
1996

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