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
S40/V50
C30
The vehicle's side impact sensors are used to provide the supplemental restraint system (SRS) early information on a side-on collision.
The four sensors that are used in the S40/V50 are:
- 1 side impact sensor in each left and right B post
- 1 side impact sensor in each left and right C post.
The four sensors that are used in the C30 are:
- 1 side impact sensor in each left and right B post
- 1 side impact sensor (pressure sensor) in each left and right door.
The side impact sensors in the B and C posts consist of acceleration sensors that continuously send data to the control module.
The side impact sensors (pressure sensors) in the doors (only C30) consist of air pressure sensors that continuously send data to the control module.
In the event of a collision, the control module uses the data from the sensors to determine if the collision force is sufficient to activate the side impact protection.
Only the side impact protection system nearest the point of impact is deployed.
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 if the communication between the control module and one of the side impact sensors does not function.
If one (or both) of the side impact sensors stops working for some reason, the control module uses information from the other sensors to determine when to deploy the impact protection.
Data is transmitted on the same cable used for power supply. There is a signal/power supply cable to each side impact sensor and a ground cable.
The side impact sensors in the B and C posts are of the same type and can be installed in all positions.
The side impact sensors (pressure sensors) in the doors (only C30) are of the same type and can be installed in either the left or right-hand door.
Each side impact has a serial number that is used to check that the right side impact sensor is installed in the vehicle.
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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.