What this code means
U1297 may indicate that the BSI radar system is not receiving expected communication from the right side BSI radar unit over B-CAN.
What the vehicle may do
- The vehicle may display a blind spot system warning.
- Blind spot assist functions may be limited or unavailable.
- The condition may appear during system startup.
Possible fault areas
- Possible right side BSI radar unit startup issue.
- Possible power circuit issue at the right side BSI radar unit.
- Possible ground circuit issue at the right side BSI radar unit.
- Possible B-CAN communication issue between the BSI radar units.
Diagnostic path
Opening context
Today we’re looking at U1297 on a 2016 to 2024 Honda Civic with the 1.5 turbo engine. In plain terms, this code is tied to the BSI radar system seeing a problem with the right side radar unit communicating over B-CAN. The vehicle may show blind spot system warnings, and the blind spot feature may be limited or unavailable. Broadly, this can involve the right side radar unit not starting correctly, a possible power or ground issue at that unit, or a communication problem between the right and left side BSI radar units.
How the code sets
The diagnostic logic is straightforward. The left side BSI radar unit expects to receive signals from the right side BSI radar unit over B-CAN. If it cannot receive those signals, the BSI radar unit treats that as an abnormal condition and stores U1297. So the first thing to keep in mind is that this is not just a sensor-performance question. The right side radar unit has to wake up normally, and its power, ground, and communication path need to support that.
Confirmation step
To confirm the condition, turn the vehicle to ON mode, then wait for at least 5 seconds. That gives the BSI radar system time to start up and make the communication check.
Testing focus
If U1297 is present after that startup check, focus on whether the right side BSI radar unit is starting normally. Check the power circuit and the ground circuit for the right side BSI radar unit. If those basics are not right, the radar unit may not come online, and the left side unit may not receive its B-CAN signals.
Verification and takeaway
After the fault path is corrected, verify the repair and confirm the code stays gone under the same startup condition: vehicle in ON mode, with at least 5 seconds for the system to initialize. The takeaway is simple: for U1297, prove the right side BSI radar unit can power up, has a good ground, and can be seen by the rest of the BSI radar system over B-CAN. For more diagnostic training, visit stepdiagnostics.com.
Final check
U1297 is best approached by confirming the startup condition, then checking that the right side BSI radar unit has the power, ground, and communication needed to come online.
For more guided automotive diagnostics, visit STEP Diagnostics.
