The Seat Belt Pretensioner System (where fitted)

The Seat Belt Pretensioner System (where fitted)

Description

The DB7 seat belt pretensioner system operates the drivers seat belt pretensioner in conjunction with the Airbag system. The seat belt pretensioner control module is located under the right hand seat, beside the right hand seat control module.

The pretensioner control module calculates changes in vehicle speed using an input signal from an accelerometer. When a collision is detected (Rapid reduction in vehicle speed) and the safing sensor in the airbag system is also activated, the pretensioner charge is fired using electrical energy stored in a capacitor within the pretensioner control module. Firing of the pretensioner charge applies additional tension to the drivers seat belt.

The airbag and seat belt pretensioner systems share the SRS (Airbag) warning lamp. Any fault detected by the pretensioner control module is indicated by constant illumination of the SRS (Airbag) warning lamp. Flashing of the SRS warning lamp indicates a fault in the airbag system.

Should both systems develop faults, the pretensioner system will permanently illuminate the warning lamp. This would mask the airbag system warning indication. Therefore, rectify the pretensioner fault and then retest for faults in the airbag system

The pretensioner control module can log up to 10 diagnostic trouble codes together with a time since each fault was alerted to the driver. Each fault will be identified as 'Permanent' or 'Intermittent' on the PDU diagnostic trouble codes screen.

System Connections

DB7 is fitted with an Autoliv EC5 or RC5 Pretensioner Control Module. The Pretensioner Control Module has an 18 pin connector featuring six shorting bridges. The mating halves of the connector may be securely locked using a double mechanical locking system.

The following pins on the control module connector are used in the Aston Martin seat belt pretensioner system:

1. Pin 1 Ground
2. Pin 2 Airbag Warning Lamp
3. Pin 11 Drivers airbag positive
4. Pin 12 Drivers airbag negative
5. Pin 14 Serial communications
6. Pin 15 12 volt positive feed
7. Case Ground

Note: Pins 1 - 2, 3 - 4, 5 - 6, 7 - 8, 9 - 10 and 11 - 12 are shorted together by internal shorting links within the connector when it is disconnected. The short circuits may be temporarily overcome for fault analysis purposes by inserting a suitable non-metallic cheater (the same size as the pegs in the controller connector) into the rectangular hole opposite the relevant pair of pins.