Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2017 Toyota Prius TwoFACTORY OEM SERVICE PROCEDURE
Occupant Classification System
OCCUPANT CLASSIFICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION [11/2015 - 12/2018]
| DTC Code | Description |
|---|---|
| B1771 | Passenger Side Buckle Switch Circuit Malfunction |
| B1780 | Front Occupant Classification Sensor LH Circuit Malfunction |
| B1782 | Rear Occupant Classification Sensor LH Circuit Malfunction |
| B1785 | Front Occupant Classification Sensor LH Collision Detection |
| B1787 | Rear Occupant Classification Sensor LH Collision Detection |
| B1795 | Occupant Classification ECU Malfunction |
| B1798 | Yaw Rate Sensor Module Malfunction |
| B1799 | Vehicle Stability Control ECU Malfunction |
| U0125 | Lost Communication with Multi-axis Acceleration Sensor Module |
| U0129 | Lost Communication with Brake System Control Module |
OCCUPANT CLASSIFICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION [12/2018 -]
| DTC Code | Description |
|---|---|
| B1771 | Passenger Side Buckle Switch Circuit Malfunction |
| B1780 | Front Occupant Classification Sensor LH Circuit Malfunction |
| B1782 | Rear Occupant Classification Sensor LH Circuit Malfunction |
| B1785 | Front Occupant Classification Sensor LH Collision Detection |
| B1787 | Rear Occupant Classification Sensor LH Collision Detection |
| B1795 | Occupant Classification ECU Malfunction |
| B1798 | Yaw Rate Sensor Module Malfunction |
| B1799 | Vehicle Stability Control ECU Malfunction |
| U0125 | Lost Communication with Multi-axis Acceleration Sensor Module |
| U0129 | Lost Communication with Brake System Control Module |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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