What Causes Airbags Not to Deploy?

[OStephanie]

Airbags not deploying does not necessarily indicate damage. It could also be because the conditions for airbag deployment were not met. Minor collisions will not trigger airbag deployment. Airbags are a passive safety system device. When a car collision occurs, the pressure sensors in the airbag system and the acceleration sensors in the ECU assess the collision. If the conditions for airbag deployment are met, both will receive signals simultaneously, causing the airbag to inflate instantly and protect the driver's head and chest, thereby ensuring personal safety. Necessary conditions for airbag deployment: 1. Vehicle speed: Generally above 50 km/h, but the key factor is the acceleration during the collision. In national certification tests, the instantaneous acceleration during collision is approximately -40g. 2. Frontal collision: The impact angle must be within approximately 60° of the front. 3. Collision object: Rigid walls or obstacles; airbags will not deploy when a car collides with soft objects at 80 km/h.

[KendraLynn]

Last time I had a similar issue with car repair, a vehicle was badly damaged but the airbags just didn't deploy. Later inspection found that the frontal impact sensors were covered in mud and engine oil, affecting signal transmission and preventing impact detection. There could also be control system issues - aging airbag modules or software failures might cause failure to trigger. Electrical problems are common too - blown fuses or short circuits can interrupt signals. Additionally, if airbags exceed their 10-year service life, the internal propellant may degrade or the airbag cushion may rupture, requiring replacement. We recommend owners get professional diagnostics annually, especially after collisions - don't delay, go immediately to authorized 4S shops or repair centers for comprehensive inspection to prevent future accidents. Keeping sensors clean is also important - just do simple cleaning of the bumper area during regular car washes.

[VanEva]

I remember a friend's car was in an accident where the airbags didn't deploy. The entire front end was crushed, but fortunately, the occupants were unharmed. Post-accident analysis revealed that the collision angle was incorrect, with an impact point skewed by over 30 degrees, causing the sensors not to activate—a common design limitation. Faults in the control unit (ECU) could also be problematic, such as electromagnetic interference leading to misjudgment or software bugs preventing deployment. Electrical connection issues, like poor contact in wiring harnesses or corroded connectors, can break the circuit. Expired airbags are another hidden danger; in older cars that have been used for seven or eight years, the airbag material may deform or deteriorate. My friend ended up spending over a thousand dollars on repairs before discovering that the sensor was faulty and needed replacement. It's crucial to regularly check the airbag light status—if it lights up briefly at startup and then turns off, it's normal, but if it stays on, get it checked immediately. Maintaining safe driving habits, such as avoiding high-speed sharp turns, can also help reduce risks.

[OJasper]

From the perspective of airbag principles, there could be several electronic reasons why it didn't deploy. Sensors are crucial—if they're contaminated or misaligned, they may inaccurately measure collisions, especially in low-speed impacts where the preset threshold might not reach the trigger point. Control system failures, such as damaged internal circuits in the airbag module or software glitches, can also cause malfunctions. Through my research on some cases, I've found that short circuits, open circuits, or voltage instability in wiring can prevent the control system from responding. Damage to the airbag itself, like a faulty inflator or blockage by foreign objects in the airbag, naturally renders it inoperable. Modern vehicles rely on complex electronic coordination, so it's recommended to check error codes via the OBD diagnostic port to avoid tampering that could affect the system. Regular software updates and system maintenance can help prevent some issues.

[JustinRose]

Looking back to the era of older cars, airbags rarely had issues, but modern vehicle systems are far more complex. Airbag failures often stem from sensor aging or contamination, where dust accumulates in the front detection zone, impairing sensing. Malfunctions in the control unit, such as burnt chips or loose connections, can also cause functional failure. Electrical issues like blown fuses or corroded/disconnected wiring may interrupt signal transmission. There's also the problem of expired airbags—over time, internal materials degrade, resulting in insufficient deployment force. Having driven many cars in my youth, I believe regular professional inspections are crucial, especially after a collision when immediate dealership diagnostics are essential. Preventive measures include keeping the interior clean to avoid obstructing airbag areas and minimizing electronic modifications that could interfere.