2019 Toyota Prius Brakes Problems

Since October 2023, your 2019 Prius has been experiencing unpredictable braking, steering, and lane-keeping interventions that seem to activate on their own — even when no correction is needed. These false alerts happen frequently on highways and during turns, creating safety concerns. You've replaced multiple parts and had sensors recalibrated at Toyota dealerships, but the problem persists because it appears to be software-related rather than mechanical. The fix will likely require a software update or ECU reprogramming from Toyota to correct the overly sensitive driver-assist system sensitivity.

The owner reported an issue with their service brakes but did not provide details in the complaint text itself (they referenced an attachment). Without more information about the specific brake problem, it's unclear whether this involves brake pad wear, reduced stopping power, brake fluid issues, or another brake system concern. A mechanic will need to inspect the brake system to diagnose and repair the issue.

When you press your brake pedal, you feel pulsation or vibration without any warning signs. After inspecting your brakes, you discovered corrosion on all four brake rotors, which is causing the pulsing sensation. The dealer confirmed the rotors need replacement but stated they're not covered under warranty and there are no recalls for this issue. Fixing this will require replacing all four corroded brake rotors.

I WAS TRAVELING AT ABOUT 55 MPH ON HIGHWAY 66 WHEN THE INSTRUMENT PANEL BEGAN FLASHING THE FOLLOWING WARNINGS: "BRAKING POWER LOW, PHSB MALFUNCTION, PARKING BRAKE LOW, PRE-COLLISION MALFUNCTION, ANTI-LOCK MALFUNCTION, LANE DEPARRURE MALFUNCTION, BRAKE OVERIDE" . THE ONLY OBVIOUS SYMPTOM WAS THAT THERE WAS NO BRAKE BOOST - THE BRAKES CONTINUED TO FUNCTION, BUT WITHOUT POWER ASSIST. I AM A FORMER AUTO MECHANIC, SO I WOULD HAVE NOTICED IF THERE WERE ANY OTHER SYMPTONS. THE DEALERSHIP HAD THE CAR FOR 3 WEEKS AND ULTIMATELY REPLACED BOTH THE BRAKE BOOSTER AND THE MASTER CYLINDER. THEY INITIALLY REPLACED THE BOOSTER AND DISCOVERED THAT THAT DID NOT FIX WHATEVER WAS CAUSING THE WARNINGS AND DTCS. TOYOTA INSTRUCTED THEM TO REPLACE THE MASTER CYLINDER AND THAT APPARENTLY FIXED THE PROBLEM. THEY COULD NOT EXPLAIN WHY A FAULT IN THE MASTER CYLIDER WOULD HAVE CAUSED THE ARRAY OF SYMOTOMS OBSERVED BY BOTH MYSELF AND THE MECHANICS. I WAS SURPRIZED THAT THE MASTER CYLINDER WAS THE CAUSE AS THE THE LOSS OF BOOST SEEMED TO BE A BRAKE BOOST PROBLEM. I WAS TOLD THAT TOYOTA IS AWARE OF THE PROBLEM AND THAT IT IS WIDESPREAD.