VW Bora Brake System Failure Traced to Faulty Sensor

I had a similar issue with my 2005 VW Golf 1.6, and as someone with moderate experience working on cars, I can share what worked for me. The symptoms you describe match exactly what I experienced, reduced brake performance and ABS warning light. Initially, I also thought it was the brake booster sensor, but when I took it to my trusted workshop, they discovered the brake system was incorrectly bled, causing air in the lines. This affected the ABS system readings and overall brake performance. The fix involved a complete brake fluid flush and proper bleeding procedure. Total cost was 90€, which included new brake fluid and labor. The vehicle safety and brake performance returned to normal immediately after the service. To help troubleshoot your specific case, could you provide: Any recent brake work or maintenance performed? Does the brake pedal feel spongy or just harder to press? Have you noticed any brake fluid leaks? Are there any unusual noises when braking? The VW Bora shares many brake components with the Golf, so the solution might be similar. Just make sure to have a proper diagnosis before replacing any parts, as incorrect bleeding is often overlooked as a potential cause.

Thanks for the detailed response. The last service was done 3 months ago at 49000km. The brake pedal feels increasingly spongy over the past week, and I can hear a slight hissing sound when pressing it. No visible brake fluid leaks under the car, but I will check the hydraulic brakes system thoroughly. I will get the brake fluid checked first before investing in replacement parts. The ABS system warning appeared right after the brake pedal started feeling different, so your suggestion about air in the lines makes sense. Better to start with the simpler fix before replacing the pressure sensor.

Thanks for the additional information. The hissing sound with your Bora is particularly telling, I had exactly that symptom with my Golf before things got worse. While bleeding helped in my case, your symptoms actually point more strongly toward a failing brake booster than just air in the lines. The hissing sound typically indicates a vacuum leak in the brake booster system. Since the noise started together with the spongy pedal feel and ABS warning, the pressure sensor could indeed be the culprit. The hydraulic brakes system might be fine, but the booster isnt providing proper assistance. After my initial brake bleeding experience, I actually had this exact issue develop 6 months later. The replacement parts for the brake booster assembly cost around 280€, but it completely resolved both the hissing and the poor brake performance. Before you proceed with any repairs, try this quick test: With the engine off, pump the brake pedal several times, Start the engine while holding the pedal down, If the pedal drops slightly, the booster works, If there is no movement and you hear hissing, the booster likely needs attention Given your symptoms are nearly identical to what I experienced, getting the brake booster checked should be a priority alongside the fluid level check.

The hissing sound combined with the spongy brake pedal definitely points to a vacuum leak issue rather than just air in the lines. Makes sense that both problems started together. I will definitely try that brake booster test you suggested before taking it to the shop. The price for the replacement parts seems reasonable at 280€ if it fixes both the brake performance issues and that annoying hissing. Good to know the ABS system warning could be related to the brake booster rather than an ABS component failure. I will have the hydraulic brakes inspected and get a proper diagnosis done. Better to fix it properly now than risk further deterioration of the brake system. If the brake booster test shows issues, I will go ahead with the replacement. Thanks for sharing your experience, it helps narrow down the likely cause rather than just throwing parts at the problem.