Toyota Prius ABS & Traction Lights Solved by Wheel Bearing Replacement

Diagnosing Prius Warning Lights

• 💡 A 2017 Toyota Prius presented with illuminated ABS, traction control, and other dash lights.
• 🎯 The primary suspect was a severely damaged rear wheel bearing, indicated by a loud growling noise and erratic wheel speed signals.
• 🛠️ The diagnostic approach involved a "parts swap out" by replacing the known bad wheel bearing, rather than extensive electronic troubleshooting.

Wheel Bearing and Brake System Issues

• ⚙️ The vehicle had recently had its caliper, rotors, and pads replaced on the affected side, suggesting a persistent brake issue.
• ⚠️ A missing inner tin shield on the wheel hub is identified as a common cause for rapid inner brake pad wear on Priuses, Subarus, and Hondas, especially in environments with dirt and salt.
• 🔧 The repair plan includes replacing the wheel bearing and the backing plate.

Wheel Speed Sensor and Bearing Diagnosis

• 🔍 The technician notes that Toyota vehicles often have issues with wheel speed sensor wiring within the connector, leading to circuit codes.
• ⚡ While the wheel speed sensor itself appeared functional, erratic signals were observed as speed increased, possibly due to rust affecting the sensor's proximity to the bearing's magnetic encoder ring.
• ⚠️ Active wheel speed sensors are described as difficult to diagnose, reinforcing the decision to proceed with the wheel bearing replacement.

Wheel Bearing Replacement Procedure

• 🔩 The process involves removing the caliper, bracket, and hub assembly.
• 🔧 A new OEM hub bearing assembly (AISIN) is installed, with a note that Napa also sells AISIN bearings.
• 🔒 Orange Loctite is applied to caliper bolts for secure fastening, and the assembly is torqued to specification.

Post-Repair Testing and Tire Discussion

• ✅ After replacing the bearing and backing plate, a test drive confirms that the ABS and traction control lights are no longer illuminated.
• 🚗 The video includes a discussion about the importance of good tires, particularly in snowy climates, contrasting them with "banana peel" tires.
• 💡 The technician shares an opinion that having four matching tires (even all-seasons) is safer than having two good tires on the front and bald tires on the rear of a front-wheel-drive vehicle.
• 📊 A recording from an Autel diagnostic tool shows the erratic left rear wheel speed signal before the repair, confirming the issue.