Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Side Impact Sensor
The side impact sensors in the car are used to measure and evaluate the collision pulses. An assessment 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 have integrated logic. In the event of a collision, they determine whether the impact was large enough to warrant transmitting an activation signal to the control module to deploy the side impact airbag. Only the side impact protection on the side from which the activation signal was sent can 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.
Data transmission occurs on the same cable used for power supply, i. e. one cable to each side impact sensor.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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