ECU ASTON MARTIN DB7 1997 Owner's Guide

Electrics
Airbag System
Airbag (Supplementary Restraint System)
Repair Procedures
Description
Two airbaes are fitted to the 97 model year DB7.
The drivers airbag is located in the centre of the
steering wheel (Fig 1-1), the passenger airbag is
located behind the fascia panel (Fig 1-2).
Figure!. Airbag Locations
The following procedures and safety precautions
must be adhered to while handling, installing and
testing airbag modules. Failure to observe these
precautions could cause the airbag to inadvertently
deploy with the risk of personal injury.
The procedures and precautionary guidelines
conform to the 'Handling and storage - The
Explosives Act 1875 & 1923' and to the 'Health and
Safety at Work Act - 1974' or local guidelines as
appropriate.
Safety Precautions and Warnings
Handling Undeployed Airbags
The electrically actuated airbag module contains
sodium azide and sodium nitrate which are
poisonous and extremely flammable substances.
Their contact with
acid,
water or heavy metals may
produce harmful, irritant gases or combustible
compounds.
The airbag module is non-serviceable and must not
be dismantled, punctured, incinerated or welded.
WARNING: Do not attempt any repairs or
electrical measurements on the airbag module.
Never measure the resistance of the airbag module,
as this may cause the airbag to deploy. Suspect
modules must be returned to Aston Martin Lagonda

Limited,
or their importer for replacement.
Tampering or mishandling can result in personal
injury.
Keep away from heat, sparks and open flames. Do
not store at temperatures exceeding 93°C (200°F).
Keep away from electrical equipment as electrical
contact may cause ignition.
Do not drop or impact the airbag module. Always
position the module 'cover-up'.
Ensure that the module connector is protected to
prevent damage. Never carry the airbag module by
the wires or connector.
Store modules in a secure lockable cabinet.
Never position material over the undeployed
module which could be projected and cause injury
in the event of inadvertent deployment.
Do not wrap arms around the module when carrying
and always carry the module with the cover and
vents facing away from the body to avoid personal
injury in the event of inadvertent deployment.
The chemical propellant mixture deploying the
airbag is a solid and therefore inhalation exposure
is unlikely even if the module is ruptured without
deployment.
As far as practical, avoid skin contact
with,
or
ingestion of, the materials present after combustion.
Exposure to high concentrations of propellant
mixture may cause headache, nausea, blurred

vision,
faintness, cyanosis, lowering of blood
pressure, tachycardia and shortness of breath.
WARNING: Sodium azide has been listed as an
'Extraordinary Hazardous Substance or
Carcinogen' by the state of
Massachusetts,
USA.
Sodium azide has been listed on the
'Right
to Know
Hazardous Substance
List'
by the state of New
Jersey and is also regarded as a 'Special Health
Hazard Substance' by the state. The propellant
mixture is sensitive to premature ignition by
electrical sources if not properly protected and
isolated.
September 1996 6-69

Electrics
Airbag System E:m3^2?
Disposal of Live Airbags
Modu
les
removed/renewed by Aston Martin dealers
are to be deployed using the following procedure.
WARNING: Never use a customer's vehicle to
deploy airbags.
Equipment Required:
Link harness

'Slave'
battery
Safety goggles to BS 2092 grade 2 or equivalent
Rubber gloves to PrEN 374 class 2 or equivalent
Ear protectors
Particulate respirator to EN 149 grade FFP 25
Deployment cage
Note: If you do not
have access
to a deployment
cage,

please
contact Aston Martin
Lagonda
Limited
Technical

Support Department for advice.
Procedure
This procedure must be performed outdoors, away
from other personnel.
Remove any loose debris from around the airbag
and ensure that no flammable liquids are present.
Assemble the disposal cabinet and fit the airbag as
shown in figure 1 in line with the following
procedures:
a) Remove the mesh guard from the rig frame.
b) Attach the guard to the frame by bolting the
hinges to the frame.
c) Ensure the relevant plate is fitted and rotate into

position.

d) Fit and secure the airbag module onto the plate.
e) Clamp the plate down using the two toggle
clamps.
f) Close the mesh guard.
Note: The harness connected between the driver's
airbag and
the
connector
has
one red
feed
wire and one
grey/orange return wire. The harness connected between
the
passenger's
airbag and the connector
has
one blue/
orange feed wire and one pink/black return wire.
Connect the 10 metre {33ft) link harness to the

airbag.

Ensure that no personnel are in the vicinity of the
cabinet.
5. Move 10 metres (33ft) and connect the link harness
crocodile clips to the 'slave' battery; the airbag will
deploy immediately.
6. Allow the unit to cool for at least 20 minutes.
7. Open the mesh guard and remove the deployed
airbag module.
Note: Should the
design
of your deployment
cage
differ
from that described above, please contact the cage
manufacturer for advice on mounting the airbag.
8. Seal the deployed module into a plastic bag ready
for disposal.
9. In the event of any problems or queries, contact
Aston Martin Lagonda Limited -Technical Services
Department.
Disposal of Deployed Airbags
Deployed airbags are to be disposed of as special
waste and disposal must comply with local
environmental requirements. If
in
any doubt, contact
the local authority for disposal instructions.
Note; The storage, transportation, disposal and/or
recycling of airbag module components must be
performed in accordance with all applicable federal,

state
and local regulations including, but not limited to,

those
governing building and fire
codes,
environmental
protection, occupational health and safety and
transportation.
Modules removed and deployed by Aston Martin
Dealers are to be returned to Aston Martin Lagonda
Limited for disposal following prior consultation.
6-74 September 1996

'=2?
Electrics
Airbag System
4.5.01.3 Driver's Airbag Module Renew
Read and adhere to all warnings and safety
procedures quoted at the start of this section when
working on airbag modules.

1.
Ensure that the steering system is centralised and
that the steering wheel is in the lowest tilt position.

2.
Disconnect the vehicle battery and insulate the
battery lead to avoid accidental reconnection. Wait
for at least one minute before proceeding with work
on the removal of the airbag.
Hote: The vehicle battery
must be
disconnected within
12 seconds of switching off
the
ignition to avoid the alarm
siren sounding.
5. Carefully remove the module from the steering
wheel and disconnect the airbag module multi-

plug.

6. To ensure personal safety, double check that the
battery is still disconnected and the battery lead
safely insulated. Connect the new airbag module

multi-plug.
Fit and align the new module to the
steering wheel and tighten the two securing torx
screws. Return the steering to the straight ahead

position.

7. Remove the battery lead insulation and reconnect
the battery
lead.

Note:
The vehicle
clockandthe window control unitwill
need
resetting
after completion of
this
procedure.
8. Switch on the ignition and check that the airbag
warni ng
I
ight comes on when the ignition is switched
on and extinguishes after approximately sixseconds
indicating satisfactory completion of the airbag
system self tests.
Insert the ignition key and turn to position I. Turn
the steering wheel to the left, 90° from its straight
ahead position, and loosen thefirstmoduiesecuring
torx screw.
Turn the steering wheehSO" to the rightand loosen
the second module securing torx screw.
September 1996 6-75

Electrics
Airbag System ^^?

7.8.02.6

Renew
Passenger's Airbag Module
Read and adhere to all warnings and safety
procedures quoted at the start of this section when
working on airbag modules.
Disconnect the battery and wait for at least one
minute before proceeding with the airbag removal.
Note:
The
vehicle battery
must
be disconnected within
12
seconds
of switchingoff
the
ignition
to
avoid the alarm
siren sounding.
2. Open the passenger airbag deployment door.
3. Release four nuts and remove the airbag module.

4.
Disconnect the airbag harness multi-plug.
5. Connect and fit the new module and secure with
four nuts.
6. Refit the airbag deployment door.
Note:
The vehicle
clock and
the
window control unit will
need
resetting
after completion of
this
procedure.
7. 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.
6.1.23.1/6.2.10.1 Airbag
Crash
Sensors
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
seconds
of switchingoff
the
ignition
to
avoid thealarm
siren sounding.

4.

5.
Raisethevehicleon a rampand remove the relevant
front roadwheel and wheel arch liner.
Disconnect the sensor connector and feed the
protected loom forward through the body aperture.
Open the bonnet and release two bolts securing the
crash sensor to the body.
Fit and secure the new sensor and feed the sensor
loom back through the body aperture.
Reconnect the sensor. Refit the wheel arch liner
and the roadwheel.
Note:
The vehicle
clock and
the
window control unit will
need
resetting
after completion of
this
procedure.
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.
6-76 September 1996

^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

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

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

^^?
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

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

o; D^?
Electrics
Airbag System
Airbag DM Fault Code 32
Drivers airbagcircuit high resistance or open circuit.
Normal Operation
The diagnostic module measures the resistance
across pins 2-4 and 2-5 every time the ignition is
switched on. The resistance should be 1.6 to
1.8£2.

This value is made up of the airbag
1
.OQ and the
cable reel cassette windings 0.3-0.4Q per winding.
If the total resistance in the drivers airbag circuit
exceeds 4.0^, fault code 32 will be declared and
the airbag lamp will be illuminated.
Note: The
resistance
of
the airbag simulator is
2.5Q,

therefore expect total resistance readings
of 2.8 - 2.9Q
with
the simulator
fitted.

Caution: The drivers airbag and the cable reel
cassette connectors contains shorting bars which
short circuit pins 1 and 3 of the connectors when
disconnected.
DO NOT REMOVE THE AIRBAG SHORTING
BAR

UNDER ANY CIRCUMSTANCES.
The harness shorting bars may be temporarily
removed during the following resistance checks.
Possible Causes
• Excessive resistance in the cable reel cassette
connections.
• Open circuitor high resistance in the cable reel
cassette windings.
• Open circuit or high resistance in the wiring
harness
• Open circuit or high resistance in the drivers
airbag module.
• Defective diagnostic module.
WARNING: Do not attempt a direct resistance
check on the airbag module. Accidental
deployment can occur due to the induced voltage
from the measuring equipment.
3.
Fault Analysis
Disarm the airbag system and fit airbag simulators
(6.4.21.4).
Disconnect the diagnostic module and remove the
plastic wedge from connector 2 (black). Measure
the resistance between pins 2-4 and 2-5. The
resistance should be 2.8 - 2.9Q.
If the resistance is 2.8 - 2.9Q, go to step 3.
if the resistance is not in the range 2.8 - 2.9D, isolate
the continuity problem noting the following:
a) Pin 2-4 is shorted to pin 2-5 by a shorting link
. when plug 2 of the diagnostic connector is

removed.
Removal of the plastic wedge from
the plug will remove the short circuit.
b) Both halves of the cable reel conneaor have
shorting links which will short pin 1 to pin 3
when the connection is removed. Removal of
the plastic wedge horn either half will remove
the short circuit in that part of the wiring.
c) A shorting link is fitted in the airbag module
connector. Do not attempt to remove this
shorting link or the plastic wedge. Do not
attempt to measure the resistance of the airbag
module.
d) Carefully replace all plastic wedges on
completion of the circuit checks.
The fault is therefore in either the airbag module or
in the airbag diagnostic module.
Substitute a known good diagnostic module. If
code 32 recurs with the airbag simulator fitted,
there is a fault in the wiring.
If the fau
It
code 32 does not recur, rearm the airbags
(6.4.21.4) and retest.
If fau
It
code 32 recu
rs
with the ai rbag modu
le
fitted,
the airbag module is faulty. Replace the drivers
airbag module (4.5.01.3).
September 1996 6-91