Porsche 991 Brake System Failure, Multiple Warning Signs

Hey! I can relate to your brake system concerns. I had similar issues with my 2015 Porsche Cayman S last summer. The symptoms were nearly identical, ABS light, unresponsive brake pedal, and system failures. In my case, it turned out to be more than just the brake pedal sensor. The ABS control module had failed, which affected multiple brake-related systems. The problem started gradually but got worse within a week. This was definitely a serious safety issue that needed immediate attention. I took it to a certified Porsche dealership since this was critical for safety. They diagnosed a faulty ABS module and also found corroded wiring harness connections affecting the brake light circuit. The whole repair took about three days, including testing. Based on your symptoms, especially with multiple systems being affected simultaneously, I'd strongly suggest getting it checked at a certified Porsche center rather than a regular mechanic. These systems are pretty complex and interconnected in modern Porsches.

Thanks for sharing that, sounds like exactly what I'm dealing with! I'm thinking I'll follow your advice and head to a certified center. Just curious, do you remember roughly how much the whole repair set you back? And has everything been running smoothly since then, or have you noticed any other issues pop up?

Hey again! Actually, I've got some good news that might save you a trip and some money. After my previous response, I took my Cayman S back to check it one more time, and turns out I was totally wrong about the ABS module and wiring, it was literally just the brake pedal position sensor not working properly. And get this, it wasn't even a mechanical issue! The fix was ridiculously simple and cost absolutely nothing. The mechanic just had to recalibrate the sensor settings which had somehow gotten messed up (basically a personal error situation). Since that quick fix, my car's been running perfectly, no more warning lights, brake system's working like a charm, and everything's back to normal. So before you head to the dealer, might be worth checking if you've got the same simple fix. Could save you a bunch of time and money! Let me know how it goes, fingers crossed it's as straightforward as mine turned out to be!

Oh wow, that's such a relief to hear! I actually just got back from the mechanic and you won't believe it, it was exactly what you described! I went to a different shop this time, a small but well-reviewed place specializing in European cars. The mechanic took one look and figured it was likely a sensor calibration issue. Took them about 30 minutes to diagnose and fix it. Just like in your case, they recalibrated the brake pedal position sensor, and boom, all the warning lights disappeared! The brake pedal's back to normal, and the ABS and DSC are working perfectly again. Best part? They only charged me for the diagnostic fee, which was way less than what I was expecting to pay. Thanks so much for your help, you saved me from potentially spending a fortune at the dealership! Sometimes the simplest solution really is the right one. Now I can finally enjoy driving my 991 again without worrying about those annoying warning lights!