What does it mean?
B1297 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Clearance Sonar ECU Communication Stop .
Symptoms
- Parking sensors are completely dead, no warning tone when reversing or manoeuvring
- Park assist warning message, or the park assist indicator stays lit
- Reversing camera guidance overlays and low-speed braking assist may be disabled
- Scan tool cannot reach the sonar module
- Other convenience functions handled by the same module stop working
Likely causes
- Blown fuse or a damaged power feed to the parking sensor control module
- Corroded or water-damaged module connector, these units are often mounted low behind rear trim
- Broken bus wire in the rear harness, especially where it flexes into the tailgate
- Corroded module ground
- Internal failure of the sonar control unit after water ingress
- Rear-end impact or bumper removal damaging the harness
- Module not configured after replacement, or after sensors were changed
How to fix it
- Run a complete module scan to confirm which node is missing from the bus
- Check the relevant fuse, then measure power and ground at the sonar module connector
- Inspect the module mounting area for water damage, dry and reseal if moisture is found
- Check the rear harness for breaks near the tailgate hinge and the bumper mounting points
- Verify bus continuity and resistance between the module and the gateway
- Replace the parking sonar module if supply and bus check out, then configure it to the vehicle
- Clear codes and test each sensor on a live data screen while walking an obstacle around the bumper