Side Impact Sensor
The side impact sensors in the car are used to measure and evaluate the collision pulses. An evaluation is then transmitted to the supplemental restraint system module (SRS).
The sensors which are used in the car are:
- 2 side impact sensors in the B-post
- 2 side impact sensors in the C-post.
The side impact sensors can transmit three different signals:
- fault in the sensor (Error)
- the sensor is working (OK)
- deployment signal (Fire).
The side impact sensors have integrated logic which, in the event of a collision, determines whether the impact was sufficient to warrant transmitting a trigger pulse to the control module to deploy the side impact airbag. Only the side impact protection on the side from which the signal was sent can normally be deployed.
The side impact sensors transmit continuous OK signals to the control module to indicate that they are working. In the event of a fault in the side impact sensor, a fault signal is transmitted to the control module which then stores a diagnostic trouble code (DTC). A diagnostic trouble code (DTC) is also stored when the control module has not received an OK signal. Each side impact sensor has a software ID. The ID is used to check that the correct side impact sensor is installed. This is because the activation level of the signal which is transmitted to the control module is not necessarily the same for the different side impact sensors.
The front (B-post) and rear (C-post) side impact sensors are a different color and have different coding on their connectors to simplify installation. The front side impact sensors cannot be installed in place of the rear sensors and vice versa.
There is a memory in the side impact sensors which stores data for up to three collisions.
This information is used in the development of collision safety systems of the future.
Data transmission occurs on the same cable used for power supply to the side impact sensor. That is a cable for power supply and data transmission and a ground lead.