What are the reasons for a car not moving when the brake is released?
4 Answers
One possible reason for a car not moving when the brake is released is that the handbrake is not fully disengaged. Below is a detailed introduction about car brakes: 1. Brake: Braking, also known as deceleration, refers to the action of stopping or reducing the speed of a running locomotive, vehicle, or other means of transportation or machinery. The braking device is a mechanical braking device that can slow down the speed, also known as a decelerator. 2. Braking system: The braking system consists of a control system, a hydraulic system, and a power assist system. The control system includes the pedal, handbrake, etc. The hydraulic system is composed of hydraulic oil, a brake pump, and hydraulic oil pipes. The power assist system is the vacuum booster pump. The electronic control system consists of an ABS pump, ABS sensors, and an ABS computer. The execution system consists of brake calipers, brake pads, and brake discs.
I've encountered this issue while driving before - releasing the brake but the car doesn't move. There are several common scenarios. The main cause is when the engine itself isn't producing power output, such as when spark plugs or the fuel delivery system malfunction. Another frequent issue is when the electronic parking brake gets stuck and doesn't fully release, especially during cold winter temperatures when it's more prone to freezing. Brake calipers not retracting smoothly or rusted/corroded parking brake cables can also cause brake drag. Contaminated fluid blocking the brake lines can produce similar symptoms. On the transmission side, clutch slippage in dual-clutch transmissions or control module failures, as well as torque converter or valve body problems in automatic transmissions, can all interrupt power delivery. Last time my car had this issue, it was due to dirty transmission fluid - the problem was resolved after a fluid change.
Veteran drivers all know this. If the car won't move, focus on checking the brake system and drivetrain. If equipped with auto hold or hill start assist, system malfunctions may keep the wheels locked. Brake discs and pads rusting together is common, especially after rainy days - that loud 'bang' when starting is usually this issue. For manual transmissions, check if the clutch is slipping; worn clutch plates lose gripping power. For automatics, listen if the engine sounds strained - torque converter damage or transmission actuator pressure loss can interrupt power transfer. Faulty tire pressure sensors sometimes trigger false protection mode too. My neighbor's Mercedes had this exact issue last time - the diagnostic computer revealed it during troubleshooting.
I've considered several possibilities: The electronic parking brake not being released is the most easily overlooked issue—nowadays, nine out of ten cars come with this feature. A malfunction in the rear drum brake adjustment mechanism can cause the shoes to constantly rub against the brake drum. I've made the rookie mistake of forgetting to shift into Drive (D) twice—only realizing it after restarting the car. During an engine bay inspection, I found that improper adjustment of the brake master cylinder push rod can also prevent the pedal from fully returning. For cars with start-stop functionality, pay attention to the battery level—if the voltage is too low, the engine won't automatically restart. Last time, I was embarrassingly stuck at an intersection during rush hour—later diagnosed as a faulty alternator regulator causing battery drain.
