What does it mean?
B1217 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Rear Right Sensor Fault .
Symptoms
- Parking aid warning lamp or fault message on the display
- Continuous beeping as soon as the system arms, rather than proportional distance tones
- Obstacles at the right rear corner are not detected while the rest of the array works
- False alarms when reversing on an empty driveway
- Whole rear parking aid disabled by the module
- The corresponding segment is missing from the parking display
Likely causes
- Internal sensor failure, often after water has worked past the sensor seal
- Sensor face blocked by mud, tar, ice, snow or a thick coat of paint
- Sensor loose, rotated or pushed into the bumper after a reversing knock or a kerb contact
- Wiring in the right rear corner chafed or crushed, often where the harness passes the wheel arch or towbar mounting
- Corroded pins in the sensor connector from salt and standing water
- Fuse, supply or ground fault at the parking aid module
- Module input circuit failure or a communication break on the sensor line
How to fix it
- Clean the sensor face and check for paint thickness, cracks, and whether the sensor is properly seated and aimed
- Compare each rear sensor's live distance value while an object is brought towards it
- Listen for the sensor's ticking with the system armed to confirm whether it operates at all
- Inspect the harness in the right rear corner near the wheel arch, towbar and exhaust for chafe and crush damage
- Check the connector for corrosion and verify supply and ground at the parking aid module
- Swap the suspect sensor with a good one from another position to prove whether the fault is in the sensor or the circuit
- Fit the correct replacement sensor or repair the harness, then clear the code and confirm every position reports