battery ASTON MARTIN DB7 1997 Owner's Manual
[x] Cancel search | Manufacturer: ASTON MARTIN, Model Year: 1997, Model line: DB7, Model: ASTON MARTIN DB7 1997Pages: 421, PDF Size: 9.31 MB
Page 193 of 421

^7
Electrics
Airbag System
6.4.21.2
Airbag 'Safing' Sensor Renew
Read and adhere to all warnings and safety
procedures quoted at the start of this section when
working on the airbag system.
1.
Disconnect the battery and wait for at least one
minute before working on the airbag system.
Note:
The
vehicle battery must be disconnected within
12 secondsofswitchingoffthe ignition to avoid the alarm
siren sounding.
^h
Note: RH drive shown,
the safing sensor is
always
on
the drivers side
of the car
2. Open the drivers door and remove the lower 'A'
post
trim.
3. Release two screws retaining the airbag safing
sensor.
4.
Disconnect and remove the airbag safing sensor.
5. Connectand securethe replacement sensor. Replace
the 'A' post
trim.
Note:
The
vehicle clock and
the
window control unit will
need
resetting
after completion of
this
procedure.
6. Reconnect the battery, switch on the ignition and
check that the airbag warning
I
ight comes on when
the ignition is switched on and extinguishes after
approximately six seconds indicating satisfactory
completion of the airbag system self tests.
6.4.21.1
Renew
Airbag Diagnostic Module
1.
2.
3.
4.
6.
7.
Read and adhere to all warnings and safety
procedures quoted at the start of this section when
working on the airbag system.
Disconnect the battery and wait for at least one
minute before working on the airbag system.
Note: The vehicle battery must
be
disconnected within
l2secondsofswitchingofftheignitiontoavoidthealarm
siren
sounding.
Disarm the airbags (6.4.21.4).
Remove the facia assembly.
Note: RH drive shown,
diagnostic module always on
passengers
side of
the
car
Disconnect the airbag control module (Fig 1-1).
Release the module from the top of the airbag
carrier assembly and remove the module.
Refit and secure the replacement airbag control
module and connect the harness connector.
Refit the facia assembly.
Rearm the airbags (6.4.21.4).
Note:
The
vehicle clock and
the
window control unit will
need
resetting
after completion of this procedure.
September 1996 6-77
Page 194 of 421

Electrics
Airbag System '=2?
Airbag System Diagnostics
System Description
The airbag system installation comprises:
Airbag Diagnostic Module
Driver and passenger airbag modules
Two front impact (crash) sensors
One 'safing' sensor
Dedicated wiring harness
SRS indicator/warning lamp
The system is designed to provide protection for
both driver and front seat passenger by automatical ly
deploying airbags in the event of
a
collision during
forward travel.
In the event of a collision, the crash and safing
sensors will operate, completing the firing circuit
and causing the airbags to inflate within 32
milliseconds. At least one crash sensor and the
safing sensor must operate to fire the airbags.
Any faults in system components, installation or
wiring will be indicated by a flashing code on the
SRS/AIRBAG warning lamp. Fault code information
may also be monitored using the PDU or scan
tool.
Component Descriptions
Airbag Diagnostic Module
The airbag diagnostic module is mounted on top of
the passenger airbag mountingcage.Thediagnostic
module contains the microprocessor which is
connected to the complete airbag system. The state
of the three system sensors, the two airbag modules
and the wiring harness is constantly monitored by
the microprocessor for faults and for sensor
activation (crash) conditions.
The diagnostic module also confirms correct supply
voltage by comparing
a
direct battery voltage input
with a similar input via the ignition switch.
The diagnostic module contains a reserve power
supply, enabling the airbags to fire even if the
supply voltage is lost due to collision damage. The
reserve power charge will be retained for
approximately one minute if the positive battery
supply is lost in a collision. An auxiliary internal
circuit known as the 'dwell enhancer' provides a
temporary ground if normal system ground was lost
in a collision.
Wiring Harness
A dedicated electrical wiring harness is used to
connect all system components to the bulkhead
harness. To allow free movement of the steering
mechanism, a cable reel cassette is used to connect
the drivers airbag in the steering wheel to the airbag
harness on the steering column.
Airbag Modules
The two airbag modules contain achargeof sodium
azide/copper oxide which wi
11
generate
a
sufficient
volume of nitrogen gas to fully inflate the airbag
when ignited by an electrical impulse. The volume
of gas is greater in the passenger side airbag due to
its larger size.
Both airbag modules, including the surrounding
trim of the drivers airbag, are non-serviceable and
once deployed, must be renewed as a complete
assembly.
Crash and Safing Sensors
The two crash sensors are mounted one at either
side of the bumper mounting cross member, outside
of the bonnet hinges.
The safing sensor is mounted in the base of the
drivers side 'A' post.
The two crash sensors and the safing sensor
determine when airbag deployment is necessary in
a crash condition.
The sensor contacts will only close when the vehicle
suffers a forward impact of sufficient force. At least
one crash sensor and the safing sensor contacts
must close before the airbags will deploy. The
doubletrigger strategy
is
used to prevent deployment
during trivial impacts such as contacts during
parking.
6-78 September 1996
Page 196 of 421

Electrics
Airbag System ^2?
6.4.21.4
Airbag Disarming/Arming
Procedures
WARNINGS AND CAUTIONS:
WARNINGS:
Disarm the airbags by disconnecting the battery
ground (black)
lead,
waiting one minute and then
removing the airbag modules before servicing of
any airbag or steering column component.
After disconnecting the battery ground
lead,
allow
a minimum of one minute delay for the back-up
power supply to discharge before servicing the
airbag system.
The system components are non-serviceable, if
faults are
suspected,
change components for new
items
only.
Failure to observe the above procedures may
result in accidental deployment of the airbags.
Always wear safety
glasses
when working on airbag
equipped vehicles.
Personnel carrying an airbag module must ensure
that the module and trim cover are pointing away
from the
body.
When positioning on a bench or
work surface, ensure that the airbag module and
trim cover face upwards to limit motion on
accidental deployment.
Always wear
gloves
when handling deployed airbag
modules. Deposits of sodium hydroxide may be
presenton the module surface. If sodium hydroxide
contacts any area of the skin, wash the affected
area immediately with mild soap and
water.
Dispose of the deployed airbag using the correct
procedures referred to in this section.
Cautions:
When scrapping vehicles,
ensure
that the
airbags
have
been deployed (see
Scrapping Vehicles
with Live
Airbags).
If a component
has been
renewed and the fault
does
not
clear,
refit the original item and repeat the diagnostic
procedure.
After
servicing,
repeatthe diagnostic
procedures
to ensure
correct
system
operation.
Renew
the airbag module if the surrounding trim
panels
are
damaged.
Do not attempt to repaint trim covers as
paint may
damage
cover material.
Disarming the Airbags
3.
4.
WARNING: Carry out the following disarming
procedure before attempting any work on the
vehicles electrical
systems.
Note: The battery ground (black) lead must be
disconnected within 12 seconds of switching off the
ignition to avoid the alarm siren sounding.
Disconnect the battery ground
lead.
Allow a
minimum of one minute delay for the back-up
power supply to discharge.
Remove the drivers side airbag module and replace
it with an airbag simulatorfrom the simulator kit (Pt
No.
43.27028).
Remove the passengers airbag module and replace
it with an airbag simulator from the simulator kit.
Reconnect the battery ground.
Rearming the Airbags
WARNING: Carry out the following procedure to
rearm and check the airbags after completing all
work on the vehicles electrical
systems.
Note: The vehicle battery
must be
disconnected within
12
seconds
of switching off
the
ignition
to
avoid the alarm
siren sounding.
^. Disconnect the battery ground
lead.
Allow a
minimum of one minute delay for the back-up
power supply to discharge.
2.
Removethedriverssideairbagsimulatorand replace
it with the drivers airbag module. Secure the airbag
module with the two captive torx screws.
3. Remove the passengers side airbag simulator and
replace it with the passenger side airbag module.
Secure the module with four nuts and washers.
Close the passenger side airbag door.
4.
Reconnect the battery ground.
5. Switch on the ignition and check for correct
indications from the SRS/AIRBAG warning light.
TheSRS/AIRBAC lamp should come on after
a
brief
delay and remain on for approximately six seconds
during the airbag system self check. The lamp will
extinguish upon satisfactory completion of the self
check, or will flash a diagnostic code if an airbag
system fault is detected. Continuous illumination of
the warning lamp may indicate a seatbelt
pretensioner fault
Note:
Reset the
clock and window
ECUs
on completion.
6-80 September 1996
Page 197 of 421

^=2?
Electrics
Airbag System
Airbag Diagnostic Module Fault Codes
Fault codes may be extracted in one of two ways:
Through the upper diagnostics connector using the PDU, or as a series of flashes of the SRS/AIRBAG warning lamp.
Each series of flashes represents a two digit number, representing a fault code from the list below which is recorded
in priority order (i.e. If two faults are present, the code nearest the top of the list will flash. Clear the first code, then
the second code will flash). Fault analysis procedures for each code are included on the following pages.
_ No Airbag warning lamp - Inoperative airbag warning lamp or no ignition voltage to the diagnostic module
Continuous airbag warning lamp- Diagnostic module disconnected or inoperative, or a seatbelt pretensioner
fault (see pretensioner diagnostics).
12 Low battery voltage
13 Airbag circuit shorted to ground
14 Front crash sensor circuit shorted to ground
21 Safing sensor incorrectly mounted in the vehicle
22 Safing sensor output circuit shorted to battery voltage
23 Safing sensor input feed/return open circuit
24 Safing sensor output feed/return open circuit
32 Drivers side airbag circuit high resistance or open circuit
33 Passengers side airbag circuit high resistance or open circuit
34 Drivers side airbag circuit low resistance or short circuit to ground
35 Passenger side airbag circuit low resistance or short circuit to ground
41 Front right crash sensor feed/return open circuit
42 Front left crash sensor feed/return open circuit
44 Front right crash sensor incorrectly mounted on the vehicle
45 Front left crash sensor incorrectly mounted on the vehicle
51 Diagnostic module internal fuse intermittent or short circuit to ground
52 Back-up power supply - overvoltage fault
53 Front crash sensor circuits resistance to ground or internal diagnostic module failure
Rapid continuous flashing of the airbag lamp (no fault code)- all front crash sensors disconnected
September 1996 6-81
Page 198 of 421

Electrics
Airbag System ^^?
Airbag Diagnostic Module Connector
The wiring to the airbag diagnostic module passes through two plugs into a single socket. Plug
1
is grey coloured,
plug 2 is black. To aid in fault analysis, the diagnostic module connector pins for plugs
1
and 2, and their functions
are listed below:
Connector 1 - Grey Colour
Pin No. Colour Circuit
Connector 2 - Black
Pin No. Colour Circuit
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
1-10
1-11
1-12
LGS
ON
B
YW
B
YU
RW
-
RN
RG
KU
KG
12V Ignition Supply
RH Crash Sensor Monitor
Ground
Airbag Warning Lamp Output
Ground
LH Crash Sensor Monitor
12V Battery Power
Not Used
Safing Sensor Input
Safing Sensor Ground Monitor
RH Crash Sensor Feed
LH Crash Sensor Feed
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
-
RP
KP
KN
RP
YG
-
OP
ow
-
YP
-
Not Used
Passenger Airbag Module Feed
Passenger Airbag Module Return
Drivers Airbag Module Return
Drivers Airbag Module Feed
Safing Sensor Output Monitor
Not Used
LH Crash Sensor Ground Monitor
RH Crash Sensor Ground Monitor
Not Used
Safing Sensor Feed
Test Input
Plug 2 Piugl
/LrLrLruuTJu—LrLrLrLrLrLnj
OOO
Connector 2/12-Way/Black
YG RP 3 KP
mn
10 9 OW
Connector 1/12-Way/Grey
6 YU 5 B
12 KG 11 KU 10 RG
4 YW
I
ON LGS
0
6
12 'I J'
6
12 J
6-82 September 1996
Page 200 of 421

Electrics
Airbag System [EE:^^^?
Continuous Airbag Warning Lamp
Inoperative lamp circuit or no ignition supply to the
airbag diagnostic module.
Normal Operation
The airbag warning lamp is designed to illuminate
for approximately six seconds when the ignition is
switched
on.
This period isallocated for satisfactory
performance of the airbag system self test. If after
this period, the diagnostic module detects a fault
within the system, the airbag warning lamp will
begin to flash.
Note:
The seat
belt
pretensioner system
(if fitted)
shares
the
airbag/SRS
warning lamp with
the airbag
system.
If a
seat belt pretensioner fault is
detected,
the
Airbag/SRS
warning lamp will be permanently illuminated. Ensure
thata permanently lit
lamp
is nottheresultof a pretensioner
fault before carrying out fault analysis on the airbag
system.
Poor connection or disconnection of the diagnostic
module harness may cause a short circuit from DM
pin 4 (warning lamp control) to pin 5 (ground) and
cause permanent illumination ofthe warning lamp.
Faulty operation of the diagnostic module internal
logic may fail to turn off the warning lamp control
circuit and cause constant illumination of the
warning lamp.
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of this section when
working on the airbag system.
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4). Reconnect the battery.
2.
Inspectthe instrument pack and diagnostic module
connectors for damaged, pushed out pins, proper
location etc.
If any defects are identified, service as necessary.
Retest to ensure correct operation of the airbag
warning light.
If the connector condition and security are good,
reconnect the connectors and go to step 3.
5.
Connect the PDU to the upper diagnostic socket
and monitorthe airbag warning lamp
signal.
Switch
on the ignition.
If the signal is permanently low, suspect a short
circuit to ground on the airbag warning lamp
control line within the diagnostic module or from
diagnostic module pin
1
-4 to earth. Co to step 4.
If the signal switches low for six seconds after
ignition on but the airbag warning lamp is
permanently illuminated, suspect a fault in the
output side of the instrument pack to the airbag
warning lamp.
Disconnect diagnostic module plug 1 (slate) and
withdraw the plastic locking wedge to prevent
shorts to other circuits. Check continuity from pin
1-1 to ground.
If a short circuit to ground is detected, service the
wiring
as
necessary. Replacethe locking
wedge,
re
insert the connector. Switch on the ignition and
check that the airbag warning lamp signal atpin 1-
4 goes high six seconds after switching on the
ignition and that the warning lamp extinguishes.
If no short circuitto ground isdetected,thediagnostic
module is faulty. Replace the diagnostic module.
Switch on the ignition and check that the airbag
warning lamp signal at pin
1
-4 goes high six seconds
after switching on the ignition and that the warning
lamp extinguishes.
Switch off the ignition. Disconnect the battery.
Rearm the airbags (6.4.21.4). Switch on the
ign
ition
and check for correct indications from the airbag
warning lamp.
6-84 September 1996
Page 201 of 421

^^?
Electrics
Airbag System
Airbag DM Fault Code 12
Low battery voltage
Normal Operation
The airbag diagnostic module (DM) monitors the
voltage at pin 1-7 which should be equal to the
battery voltage. If a voltage lower than 9 volts is
detected at pin 1-7, the airbag warning lamp will be
illuminated and fault code 12 will be flashed.
Possible Causes
Drop in battery voltage to DM pin 1-7 caused by:
• Open circuit to pin
1
-7 from the battery
• Short circuit to ground on the battery feed
circuit
• Safing sensor feed shorted to ground
• Safing sensor internal short to ground
• Faulty charge system draining the battery
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of
this
section when
working on the airbag system.
1.
Complete a battery voltage test as follows:
a) Measure the battery voltage at the battery under
KOEO and KOER conditions.
If the battery voltage is below 10.5 volts during
KOEO or below 12.5 volts during the KOER tests,
service the battery
and
charging system
as
necessary.
Retest for airbag system fau
It
code 12 and go to step
2 if the fault recurs.
2.
Complete a 12 volts supply check at the diagnostic
module:
a) Disarm the airbag system and fit airbag simulators
(6.4.21.4)
b) Disconnect the airbag diagnostic module.
c) Switch on the ignition.
d) Measurethevoltagebetween DM hamessconnector
pin 1-7 (+) and harness connector pin 1-3 (-).
e) If battery voltage is not present, go to step 3.
If battery voltage is present at pin 1-7, renew the
diagnostic module. Rearm and verify the airbag
system.
3. Check the supply fuse as follows:
a) Check fuse F16 in the passenger side fusebox RHD
(or F18 in passenger fusebox LHD).
If the fuse has not blown, check for an open circuit
between battery positive and diagnostic module
connector pin
1
-7.
If the fuse has blown. Renew the fuse and/or repair
the wiring and go to step 4.
4.
Check for a short circuit as follows:
a) Switch off the ignition. With the airbag diagnostic
module disconnected, measure the continuity to
earth from diagnostic module connector pin
1
-7 to
ground.
If no short circuit is detected, go to step 5.
Ifashortto ground isdetected, service the wiring as
necessary. Reconnect the diagnostic module and
retest to ensure that code 12 is cleared.
5. Check for a short circuit to ground on the safing
sensor wiring as follows:
a) Check for a short circuit to ground at diagnostic
module pin 1-9.
b) If a short is detected, disconnect the safing sensor
and repeat the check at diagnostic module pin
1
-9.
If a short is still detected, service the wiring from
diagnostic module pin
1
-9 to safing sensor pin 7.
c) If no short circuit is detected, change the airbag
diagnostic module. Reconnect the diagnostic
module and retest to ensure that code 12 does not
recur.
6. Rearm the airbags (6.4.21.4)
September 1996 6-85
Page 203 of 421

mxm^^^?
Electrics
Airbag System
Airbag DM Fault Code 14
Primary crash sensor circuit short to ground
Airbag DM Fault Code 21
Safing sensor insecure mounting.
Normal Operation
The diagnostic module measuresthevoltage at pins
1
-2 and
1
-6. The normal voltage at these pins is 10
volts (±1 volt) with the ignition on, and battery
voltage with the ignition off.
If the voltage at the airbag diagnostic module
connector pins
1
-2 or
1
-6 drops below 5 volts, fault
code 14 will be generated and the airbag warning
lamp will be switched on. When generating a code
14 the diagnostic module also generates a signal to
blow its own internal thermal fuse. This action
disables the airbag deployment circuit. The airbag
diagnostic module fuse is non-repairable and the
module must be replaced after removing the short
circuit. If the voltage at pins 1-2 and 1-6 returns to
normal,
fault code 51 (blown thermal fuse) will be
logged.
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of
this
section when
working on the airbag system.
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4)
2.
Disconnect the airbag diagnostic module and
remove the plastic wedge from plug
1
(slate).
Note:
The
plastic wedge contains a shorting bar which
would
short
together pins
1-3
(gnd),
1-11
and 1-2 when
the plug is disconnected.
3 Measure the continuity to ground at the following
pins on the diagnostic module harness connector:
1-2 RH crash sensor monitor
1-11 LH crash sensor feed
1
-6 LH crash sensor monitor
1-12 RH crash sensor feed
If no short circuit is detected, go to step 4.
If a short circuit
is
detected, disconnect the relevant
crash sensorandrepeatthecontinuity measurement
to isolate the circuit fault. Service the wiring or
replace the crash sensor as necessary. Refit the
plastic wedge to the diagnostic module connector.
Fit a new airbag diagnostic module and rearm the
airbags (6.4.21.4).
Normal Operation
The diagnostic module measures the resistance
between pins
1
-10 (safing sensor case ground) and
1-3 (monitor reference ground) at the diagnostic
module connector. If the resistance is greater than
2Q
a
fault code
21
will be generated and the airbag
warning lamp will be switched on.
Note:
a
good ground connection is vital.
The
wire from
pin
1-1
is riveted to the safing
sensor case
and the
case
must
be securely
grounded to the vehicle
body.
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of this section when
working on the airbag system.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Disconnect the diagnostic connector and check for
continuity from pin 1-3 to chassis ground.
If continuity is good, go to step 3.
If the resistance reading is 2Q or more, service the
diagnostic module ground circuit to pin 1-3 as
necessary. Confirm a good ground path between
pins 1-10 and 1-3.Clearthecode21 and rearm the
airbags (6.4.21.4).
Check for continuity between pins
1
-10 and chassis
ground at the safing sensor.
If the resistance is above 2Q, check for continuity
from the safing sensor connector pin 5 to chassis
ground.
Also check the safing sensor mounting for
corrosion,
dirt or loose fixings. Service the wiring
and/or clean and secure the sensor mounting as
necessary, if a satisfactory ground is not achieved,
replace the safing sensor.
Make
a
final continuity test from diagnostic module
connector pin
1
-3 to
1
-10 to ensure a satisfactory
ground
path.
Reconnect the diagnostic module.
Clear the code
21.
Rearm the airbags (6.4.21.4).
September 1996 6-87
Page 204 of 421

Electrics
Airbag System [D:B3-2?
Airbag DM Fault Code 22
Safing sensor output circuit shorted to battery
voltage.
Normal Operation
The diagnostic module measures the voltage at pin
2-5 (airbag module feed) and 2-5 (safing sensor
output monitor) at thediagnosticmoduleconnector.
The voltage at these pins is dependant on charging
system voltage as shown in the table below. If the
voltage at either pin exceeds 5 volts,
a
fault code 22
will be generated.
in 2-5
2.3V
2.4V
2.5V
2.7V
2.8V
3.0V
3.1V
3.2V
3.4 V
3.5V
3.7V
3.8V
4.0V
4.1V
4.3V
Pin 2-6
2.3V
2.4V
2.5V
2.7V
2.8V
3.0V
3.1V
3.2 V
3.4 V
3.5V
3.7V
3.8V
4.0V
4.1V
4.3V
Charge Volts
9.0V
9.5V
10.0V
10.5V
11.0V
11.5V
12.0V
12.5V
13.0V
13.5V
14.0V
14.5V
15.0V
15.5V
16.0V
Possible Causes
• A short between pins 2-5 or 2-6 and another
wire.
(The wiring to the safing sensor carries
voltages above 5 volts).
• A short between the cable reel cassette circuit
and other 12 volt circu its at the steering column
head.
• A short across the normal ly open contacts of the
safmg sensor.
• Vehiclechargingsystem voltage too
high.
If the
generator output is greater than 17V, fault code
22 may be logged.
Fault Analysis
WARNING: Read and adhere to all warnings and
safety procedures at the start of this section when
working on the airbag system.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Check the voltage at the battery with the engine
running at approximately 1500 rpm.
If the voltage is 14.8 ±0.5 volts, the charging
voltage is within specification, go to step 3.
If the voltage is significantly above 14.8 volts (the
voltage regulator set point) service the charging
system.
Clear the code 22. Rearm the airbags
(6.4.21.4)
Check in the area of the diagnostic module
connector for harness damage which could cause
a short circu it to 12 volts. (Note: The airbag system
harness runs are sheathed in black plastic protection
and harness damage is unlikely.)
If no harness damage is evident, go to step 4.
If harness damage is identified, service the wiring as
necessary. Clear the code 22. Rearm the airbags
(6.4.21.4).
Switch on the ignition. Monitor the voltage at pins
2-5 and 2-6 whilst rotatingthe steering from lock to
lock in both directions.
If the voltage at both pins remains below 5.0 volts,
go to step 5.
If the voltage rises to above 5.0 volts, service the
cable reel cassette or wiring as necessary. Clear the
code 22. Rearm the airbags (6.4.21.4).
With the ignition on, check the voltage at pins 2-5
and 2-6 whilst manipulating the bulkhead and
safing sensor harnesses.
If the voltage rises above 5.0 volts, service the
wiring fault in the harness area being manipulated
at the time the voltage rise occurred.
If no voltage rise occurs, fit a new safing sensor as
the most likely cause of the code 22. Clear the code
22 and rearm the airbags (6.4.21.4).
6-88 September 1996
Page 205 of 421

>^ '—-y ^ Electrics
-^ ^ ^ Airbag System
Airbag DM Fault Code 23
Safing sensor input- battery feed/return open circuit.
Normal Operation
The diagnostic module measures the voltage on
diagnostic module pin
1
-9 at all times. The voltage
can be as high as 25 volts when the backup power
supply is fully charged.
Pin
1
-9 is connected to pin 2-11 inside the safing
sensor and the voltage on both these pins shou
Id
be
the same. If the voltage on pin 2-11 fails below the
voltage on pin
1
-9, a code 23 is generated.
Possible Causes
• Open circuit in the wiring to diagnostic module
pin 1-9.
• Open circuit in the wiring to diagnostic module
pin2-n.
Fault Analysis
WARNING: Read and adhere to all
warnings
and
safety procedures at the start of
this
section when
working on the airbag
system.
1.
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
2.
Disconnect the diagnostic connector and thesafing
sensor connector. Check for continuity from DM
pi n 1
-9 to safing sensor harness connector
pi n
7 and
from DMpin 1-11 to
safing
sensor harness connector
pin 6.
If the continuity of both leads is good, go to step 3.
If a continuity fault is detected, repair the wiring as
necessary. Reconnect ail components. Clear the
code 23. Rearm the airbags (6.4.21.4).
3. Check the continuity between pins 6 and 7 of the
safing sensor.
If the continuity is good, replace the diagnostic
module. Rearm the airbags (6.4.21.4).
If a continuity fault is detected, replace the safing
sensor. Reset the code 23. Rearm the airbags
(6.4.21.4).
September 1996 6-89