What Are the Reasons for the Brake Pedal Being Hard to Press and the Car Failing to Start?

[AlejandroDella]

The reasons for the brake pedal being hard to press and the car failing to start include a leaking vacuum booster pump or a damaged brake booster pump. Below are the specific explanations: 1. Vacuum Booster Pump Leakage: If the car's vacuum booster pump is leaking or malfunctioning, it should be noted that the force applied to the brake pedal is amplified by the brake booster pump. If it fails, the brake loses its power assistance, making it difficult to press down. 2. Brake Booster Pump Damage: Pressing the brake pedal after turning off the engine is also related to the brake booster pump. The brake booster pump only continuously generates vacuum when the engine is running. When the engine is off, it relies solely on the residual vacuum assistance left from previous operations.

[SanJasmine]

I'm an experienced driver, and there are generally three possibilities when encountering a situation where the brake pedal can't be pressed and the car won't start. First, there might be an issue with the vacuum booster. After the engine shuts off, if the residual vacuum is depleted, the brake pedal becomes as hard as a rock. Second, it could be due to a weak battery. Nowadays, cars with push-button start require detecting the brake signal to start. If the battery is too weak, even this detection can't be completed. Third, it might be a faulty brake switch. If the pedal position sensor is broken, the car's computer won't know you've pressed the brake. Last week, my neighbor's car broke down in the middle of the night because of this, and it turned out that mice had chewed through the brake switch wiring. My advice is to first try jump-starting the car if you encounter this situation. If that doesn't work, don't force it—calling a tow truck is the safest option.

[JasmineFitz]

I've repaired many cars with similar issues where the brake pedal is hard to press and the engine won't start. It's most likely related to the brake booster system. After the engine shuts off, the vacuum reservoir can only maintain brake assist for two or three applications. If the car is parked for a long time and the vacuum is depleted, this situation occurs. Another possibility is a damaged or improperly adjusted brake light switch. That small switch is responsible for sending the brake signal to the ECU - if it fails, pressing the pedal all the way won't help. Also, don't overlook electrical issues; blown fuses or water ingress in control modules can interrupt the signal. Some novice drivers tend to stomp the pedal frantically when encountering this problem - absolutely avoid doing that as it can easily damage the booster pump's diaphragm. A simple self-check method is to turn the key to the ON position without starting the engine, then press the brake pedal several times to listen for any hissing sounds of air leakage.

[NadiaLee]

I've encountered this issue twice. The first time was on a freezing winter morning when the battery was completely dead, and the brake pedal was as hard as iron. The second time was due to poor contact in the brake switch, which the 4S shop technician fixed in just five minutes. Nowadays, vehicles with one-button start are all designed this way - pressing the start button without depressing the brake pedal only powers up the electrical system. Most cases stem from electrical circuit problems: aging batteries, blown fuses, corroded wiring harnesses, or oxidized switch contacts. It's advisable to regularly check your brake lights. If you notice the taillights don't illuminate when pressing the brake pedal, it's time to be alert. In cases where the vehicle really won't start, you can try placing the key against the one-button start as an emergency measure.