The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2020 Mazda CX-5 Blind Spot Monitoring Malfunction

0

Mike T. · rep 0 · May 25, 3:35 AM · 1 replies · solved · Question

Vehicle: 2020 Mazda CX-5 Touring

My 2020 Mazda CX-5 Touring is having issues with its Blind Spot Monitoring (BSM) system. Out of nowhere, I started getting a 'BSM System Malfunction' warning on the dashboard. It's intermittent at first, but now it seems to be on almost constantly.

The sensors on the side mirrors light up sometimes, but then the warning comes back, and they stop working. I've tried cleaning the rear bumper where the radar sensors are located, but that hasn't helped. Is this a common problem with these models?

Could it be a loose connection, a faulty sensor, or something more complex with the control module? I'm hoping it's not an expensive fix.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:35 AM

0

ClearTheCode admin answer:

An intermittent or constant 'BSM System Malfunction' warning on your 2020 Mazda CX-5 is a common concern, and it typically points to an issue with the radar sensors, their wiring, or the BSM control module itself.

Here's a breakdown of potential causes and steps:

  1. Sensor Obstruction/Damage:

    • Location: The BSM radar sensors are located behind the rear bumper, usually on the left and right corners.
    • Inspection: While you've cleaned the outside, physically inspect the bumper area for any signs of impact, even minor ones, that could have misaligned or damaged the sensors. Ensure no dirt, mud, or ice is accumulated directly on the bumper skin over the sensor locations.

  2. Wiring and Connections:

    • Vulnerability: The wiring harnesses for these sensors can be exposed to road debris, moisture, or even rodent damage.
    • Check: A shop would typically remove the rear bumper cover to inspect the sensor connectors and wiring for corrosion, frays, or loose connections. A loose connection can cause intermittent faults.

  3. Sensor Failure:

    • The radar sensors themselves can fail internally, especially with age or exposure to harsh conditions. This is a common component failure.

  4. BSM Control Module Issues:

    • Less common but possible, the BSM control module (which processes data from the sensors) could be faulty. This often requires professional diagnosis.

  5. Diagnostic Trouble Codes (DTCs):

    • A specialized scanner can read codes from the BSM system. Common codes might include U0155 (Lost Communication With Instrument Panel Cluster (IPC) Control Module) if it's a communication issue, or specific manufacturer codes related to sensor performance or internal faults. These codes are crucial for pinpointing the exact problem.

When to See a Shop: Since BSM is a safety system, it's highly recommended to have a professional diagnose this. They can use specialized diagnostic tools to read BSM-specific fault codes, check sensor calibration, and test the wiring and module. Attempting to access the sensors behind the bumper without proper knowledge can be difficult and may cause further damage. A dealership or an independent shop specializing in advanced driver-assistance systems (ADAS) would be your best bet.

Menu

Help & account