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.
Rear-End Collision
USA/CDN
Other
In the event of a rear-end collision, the supplemental restraint system module (SRS) (4/9) evaluates the force of the collision pulse. If the collision pulse is powerful enough, a deployment signal (current pulse) is sent to the front belt tensioners (8/33 and 8/34) and the front waist belt tensioner (8/92) (certain markets only). The belt tensioners are deployed.
Supplemental restraint system module (SRS) also sends a collision signal on a directly connected line to Central electronic module (CEM) (4/56) and Phone module (PHM) (16/60) (not USA/CAN) when the collision protection has been activated.
A collision status signal is also sent to Central electronic module (CEM) and Phone module (PHM) (not USA/CAN) on the CAN-net. These two control modules make sure that:
- switch off the fuel pump (FP)
- switch off the windshield wipers when the car is stationary
- turn off defrosting of windows and rearview mirrors if the vehicle is stationary
- light the interior lighting
- light the flashing hazard lights
- unlock the central locking system
- send an automatic alarm to CSC (Customer Service Center) when an accident has occurred - provided the vehicle is equipped with Volvo On Call (Plus).
- turn off the fuel engine heater
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.