Pretensioner Squib High Resistance; Pretensioner Squib Low Resistance - Aston Martin DB7 Workshop Manual

D=27
Electrics
Seat Belt Pretensioner
050C Pretensioner Squib High Resistance 050D Pretensioner squib low resistance
050C w i l l be logged if the resistance of the
pretensioner squib circuit rises above 4.5 ±0.5C2
050D w i l l be logged if the resistance of the
pretensioner squib circuit falls below 1.4 ±0.4Q
Procedure
Read the warnings given at the start of this
pretensioner diagnostics section.
Connect the PDU to the lower diagnostic socket
and access the pretensioner control module. Verify
that an 050C code is logged and note if the fault is
shown as internnittent. Note any other codes in the
DTC log and then clear ail codes.
Switch off the ignition and wait at least 10 minutes
for the pretensioner squib firing capacitors to fully
discharge before continuing with this procedure.
Disconnect the pretensioner squib connector at the
rearward harness. Disconnect the pretensioner
control module and temporarily cheat the squib
shorting link.
3.
Procedure
Read the warnings given at the start of this
pretensioner diagnostics section.
Connect the PDU to the lower diagnostic socket
and accessthe pretensioner control module. Verify
that an 050D code is logged and note if the fault is
shown as intermittent. Note any other codes in the
DTC log and then clear all codes.
Switch off the ignition and wait at least 10 minutes
for the pretensioner squib firing capacitors to fully
discharge before continuing with this procedure.
Disconnect the pretensioner squib connector atthe
rearward harness. Disconnect the pretensioner
control module and temporarily cheat the squib
shorting link.
Note: The control module harness connector has a
shorting link which short circuits the squib lines together
when the connector is displaced. Carefully insert a
suitable non-metallic cheater to remove the short circuit
between pins 11 and 12 before continuing with fault
diagnosis.
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Insert cheater here
Check the continuity of the squib feed and return
lines. If any significant resistance is measured,
service the wiring as necessary.
Also check the condition of the connector pins for
damage or lack of tension and service as necessary.
If the circuit resistance is acceptable and the
connector pins are good, go to step 6.
If any defects are identified and serviced, go to step
7.
If the checks in step 4 are good, the high circuit
resistance must be in the pretensioner squib or in
thecontrol module. Replace the pretensioner squib
and reconnect all components.
Clearall logged DTCs from the pretensioner control
module and then test the vehicle.
If the 050C code is logged again, replace the
control module.
Note: The control module harness connector has a
shorting link which short circuits the squib lines together
when the connector is displaced. Carefully insert a
suitable non-metallic cheater to remove the short circuit
between pins 11 and 12 before continuing with fault
diagnosis.
Insert cheater here
Check the continuity from the squib feed line to the
squib return line. With the shorting link cheated,
the resistance should be more than lOkQ. If the
resistance is less than 10kQ, service the wiring as
necessary.
Also check the connector pins for any damage
which could cause an unintentional short circuit.
If the checks in step 5 are good, the low circuit
resistance must be in the pretensioner squib or in
thecontrol module. Replace the pretensioner squib
and reconnect all components.
Clearall logged DTCs from the pretensioner control
module and then test the vehicle.
If the 050D code is logged again, replace the
control module.
September 1996 6-107