See also:

BLIS and/or CTA fault operation
If the BLIS and/or CTA senses a fault on either the left or right sensor, the BLIS alert indicator will go on and remain on and the message center will display BLIND SPOT SYSTEM FAULT or CROSS TRA ...

Reporting safety defects (Canada only)
If you believe that your vehicle has a defect which could cause a crash or could cause injury or death, you should immediately inform Transport Canada, using their toll-free number: 1–800–333–0510 ...

Blocked sensor
An extreme build-up of materials on the left and/or right quarter panel fascias such as mud or snow can cause degraded performance of the BLIS . Also, heavy rain can cause the same effect. ...