What causes the Golf 7 brake failure and failure to start?
2 Answers
Possible reasons include excessive carbon buildup, a faulty carbon canister solenoid valve, or fuel injector leakage. Below is a detailed explanation of the Golf 7 brake failure and failure to start: Excessive carbon buildup: Caused by carbon deposits on the idle speed motor, intake tract, intake valves, and combustion chamber. When there is too much carbon or dirt in the intake tract, the cross-sectional area of the air passage changes, leading to an overly rich or lean air-fuel mixture, resulting in abnormal combustion, engine shaking after starting, or even failure to start. Fuel injector leakage: Leakage or excessive carbon buildup can cause a lean air-fuel mixture during startup, making it difficult to start. Carbon canister solenoid valve: A malfunction in the carbon canister or its solenoid valve can also lead to difficulty in starting.
Last time my friend's 7th-gen Golf also had the issue of failing to start due to brake system failure, which was really annoying. After careful inspection, I found the most common cause is a faulty brake pedal position sensor. This component must send correct signals to the ECU during startup - otherwise the engine won't start even if you turn the key. The Golf 7's design heavily relies on electronic safety mechanisms. For instance, the keyless start system requires you to press the brake pedal to respond. If the sensor ages or gets short-circuited by water ingress, the system may falsely determine the brake isn't pressed and lock the starting function. I recommend first scanning for trouble codes at a repair shop with a diagnostic tool - usually replacing the sensor solves it. Occasionally, poor contact in brake wiring can also affect signal transmission, so a thorough check of wiring and fuses is necessary.
