What are the reasons why a car key cannot start the vehicle?
2 Answers
If a car key cannot start the vehicle, it is likely due to one of the following reasons: the car key battery is dead; the car's battery is dead and cannot detect the key; or there is an issue with the key fob or sensor module. Below are the detailed explanations for why a car key may fail to start the vehicle: Specific reasons why a car key cannot start the vehicle: The car's steering wheel is locked, activating the anti-theft function; the gear is not properly engaged; or there are faults such as a damaged car engine, ignition system, relay, or a dead battery. Solutions for when a car key cannot start the vehicle: Take good care of the key. Avoid placing it near metal objects; do not keep the spare key inside the car; avoid placing the smart key near electronic devices; and do not expose the key to high temperatures or liquids. Functions of a car key: Remote window opening; automatic trunk opening—some car remote keys have a trunk release button. Press and hold the trunk unlock button (or press it twice for some models) to automatically open the trunk; parking lot car locator—some car keys feature a red horn-shaped button that serves both as a car locator and an emergency alarm. If you suspect someone suspicious is nearby, pressing this button will make the car horn sound continuously to attract attention; closing windows after turning off the engine—after parking and turning off the engine, press and hold the lock button on the remote key to close the windows. Some cars automatically roll up all windows when the remote locking function is activated.
I just encountered this situation last month. The mechanic said it could be several common issues: the key battery is dead—the dashboard lights up but the engine doesn’t respond; the car battery is old and doesn’t have enough voltage—you’ll notice the headlights dimming; the steering wheel is locked and jamming the ignition switch—you’ll need to wiggle the steering wheel while turning the key; the starter motor brushes are worn out, especially in cold weather; or the ignition switch contacts are burnt. The most frustrating part was when my car had a faulty starter relay—a tiny part costing just a few bucks. It’s recommended to use a multimeter to check the battery voltage; if it’s below 11.8V, it won’t hold a charge. Oh, and for cars with mechanical keys, also check if the immobilizer chip has failed—my colleague’s car wouldn’t start after getting caught in the rain because of this.
