What are the reasons for the failure of car auto-locking?
3 Answers
Car auto-locking failure is caused by poor wire contact or door lock damage, and it may also be a program malfunction issue, requiring inspection and repair at a service center. The purpose of the auto-locking function is theft prevention, allowing the doors to lock quickly after driving to prevent door-pull robberies during traffic jams or at red lights, providing a certain level of security. The car auto-locking function, also known as speed-sensing auto-lock, is an electronic device that automatically presses the lock button on the door when the vehicle speed reaches a computer-set value, preventing accidental door opening. The set value is generally factory-set, usually between 10 to 20 kilometers per hour.
Last time I got my car repaired, the mechanic mentioned that automatic locking failure is quite common. It's mainly due to the small motor in the door lock actuator being broken or stuck - this part is responsible for pushing the lock tongue and is prone to wear after long-term use. Additionally, the contact switch on the door is also prone to issues; it's responsible for detecting whether the door is properly closed, and if there's poor contact or water damage, it can misjudge the status. Wiring aging and breakage is another cause, especially the wiring harness connecting the body and door which is prone to breaking from repeated folding. If the body control module gets damp or water damaged, it's more troublesome as the entire control unit needs replacement. Blown fuses are also common, requiring systematic troubleshooting. It's best not to attempt DIY disassembly - using professional equipment to read fault codes is the reliable approach.
I had this exact issue with my eight-year-old car. Found that an improperly closed trunk or accidentally activated child locks could interfere with the auto-locking function. Later experienced a situation where the remote key fob battery died—though the car could start, the weak signal made the system unresponsive. Accumulated dirt around the door hinges also once caused sensor malfunctions, which resolved after cleaning. If the lock mechanism makes clicking noises, it's usually due to a disengaged or jammed internal spring. Avoid parking with tires pressed against curbs, as tilting the body can deform locking components. Never blast high-pressure water directly into keyholes during car washes to prevent water ingress and short circuits. A temporary fix is developing a habit of manually locking doors.
