The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2017 IS 300 Blind Spot Monitor (BSM) Warning Light On - Not Working

0

Chris P. · rep 0 · May 25, 3:28 AM · 1 replies · solved · Question

Vehicle: 2017 Lexus IS 300 F Sport

Hey everyone,

My 2017 Lexus IS 300 F Sport has an issue with the Blind Spot Monitor (BSM) system. The BSM warning light on the dash is constantly on, and the system itself isn't working. I don't get any warnings in the mirrors when cars are in my blind spot.

I've checked the BSM button to make sure it's not accidentally turned off, and it's definitely on. I've also tried cleaning the rear bumper area where the sensors are located, thinking it might just be dirt or mud, but that didn't help. There haven't been any recent accidents or bodywork done.

Has anyone had this problem with their IS 300? Is this something I can troubleshoot myself, or does it sound like a sensor replacement or calibration issue? Any advice would be appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:28 AM

0

ClearTheCode admin answer:

An illuminated Blind Spot Monitor (BSM) warning light on your 2017 Lexus IS 300 F Sport indicates a fault within the system. While cleaning the sensors was a good first step, the issue often lies deeper.

1. Sensor Blockage/Damage:

  • Physical Inspection: Even without an accident, the BSM sensors (located behind the rear bumper corners) can be affected by minor impacts, parking bumps, or even heavy grime that isn't easily visible. A slight misalignment or internal damage to the radar unit can trigger the warning.
  • Aftermarket Accessories: Ensure no aftermarket trailer hitches, bumper guards, or tint that might interfere with radar signals have been installed recently.

2. Wiring and Connections:

  • The wiring harness connecting the BSM radar sensors to the main BSM control module can become damaged or corroded over time, especially in areas exposed to road salt and moisture. A loose or damaged connector can cause intermittent or constant faults.

3. BSM Module Malfunction:

  • The BSM control module itself, typically located in the trunk area, can fail. This module processes the radar data and communicates with the vehicle's ECU. A fault here will disable the entire system.

4. Calibration Issues:

  • If a sensor or the module has been replaced, or if the rear bumper has been removed and reinstalled, the BSM system often requires recalibration using specialized diagnostic tools. Incorrect calibration will prevent the system from functioning correctly.

When to See a Shop: Given that cleaning didn't resolve the issue and there's no obvious physical damage, it's highly recommended to take your IS 300 to a Lexus dealership or a shop with advanced diagnostic capabilities. They can:

  • Scan for DTCs: Use a diagnostic scanner to read specific BSM-related trouble codes (e.g., B1580, B1581 for radar sensor circuit malfunctions; B1582 for calibration issues). These codes will pinpoint the exact sensor or module at fault.
  • Perform Sensor Calibration: If a sensor or module is replaced, or if misalignment is suspected, they can perform the necessary radar sensor calibration.
  • Inspect Wiring: Thoroughly check the wiring harness and connectors for continuity and damage.
Menu

Help & account