How the car responds when the driver turns the key can indicate where the problem lies, so the first step to troubleshooting is inserting the key and turning it. If the dashboard doesn't light up and the engine makes no sound, the problem might lie with the battery.
Drivers should first check the wires connecting to the battery, as corrosion or buildup can cause the battery to temporarily fail. After reattaching the cables and cleaning the battery's terminals, driver can try to jump start the car; if it starts, the battery might need to be replaced. A failing battery can also cause the engine to turn over but not start.
Other potential problems lie with the starter and ignition switch. If either of these components fail, the car might fail to turn over or fail to start consistently. If the car turns over but doesn't start or starts inconsistently, drivers need to check a number of engine components or hire a mechanic to do the checking.
If the car starts but the engine dies when it idles, drivers can try inspecting the spark plugs and replace any that are faulty. A dying engine might also indicate a problem with the fuel injector or fuel lines.