2022-2025 GR86 & BRZ Blind Spot Radar Failure: Diagnosis and Replacement Guide

Identifying the Part: Radar Sensor vs. Video Camera

First, let's clear up a common point of confusion. The part responsible for the blind spot monitoring system is a radar sensor module, not a video camera. These sensors are located behind the left (driver-side) and right (passenger-side) corners of the rear bumper. The part numbers covered in this guide—Subaru's 87611CC001 and Toyota's SU00308762 and SU00310876—all refer to this radar sensor. While your car does have cameras for other systems (like Subaru's EyeSight), they are not involved in blind spot detection.

Compatibility Warning

Common Symptoms of Failure

When a blind spot radar sensor fails, your vehicle will usually alert you with a specific message on the dashboard. Here are the most common symptoms:

• "Blind Spot Monitor Unavailable" or "Check BSM System" Message: This is the most direct indication of a problem. The system has run a self-check and detected a fault.
• Warning Light on Dash or Mirror: A persistent warning light related to the BSM or traction control system may illuminate.
• BSM Light Stays On: The warning indicator on the side mirror may stay lit continuously, even when no car is present.
• No Alerts: The system may fail to detect vehicles entirely, providing no warnings when cars are in your blind spot.
• False Alerts: The system may alert you to a vehicle when none is there, or the light may flash erratically.

Often, the first thing to check is for simple obstructions. Dirt, mud, snow, or even heavy rain can block the sensor's view and cause a temporary error message. Always clean the rear bumper corners thoroughly before assuming the sensor has failed.

Known Issues, TSBs, and Recalls

As of early 2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) for blind spot sensor *failure* on the 2022-2025 Subaru BRZ and Toyota GR86. However, some related issues and general knowledge apply:

• DTC B2329: A Reddit user reported a Diagnostic Trouble Code (DTC) B2329, indicating an "incomplete radar alignment state." This occurred after a front-end accident, highlighting that system faults can arise even if the sensor itself isn't directly impacted.
• Heat-Related Issues: On other vehicle platforms, excessive heat has been known to cause temporary or permanent sensor failure. While not a documented widespread issue for the BRZ/GR86, it's a possibility in very hot climates if the bumper cover heats up significantly in direct sunlight.
🎬 Watch: How excessive heat can trigger blind spot sensor failures.
• Rear Turn Signal Recall (2022 Models): A recall (NHTSA #23V-609) was issued for some 2022 BRZ and GR86 vehicles for faulty rear turn signals that could fail in bright sunlight. This is unrelated to the blind spot sensors but involves the rear lighting assemblies in the same area of the car.
🎬 See this video for details on the 2022 model recall.

Buying a Used Blind Spot Radar Sensor

A used OEM sensor can be a great value, but it requires careful inspection. Since aftermarket options are virtually non-existent and often unreliable for ADAS components, a recycled OEM part is often the best alternative to an expensive new one.

What to Check Before Buying:

• Verify the Part Number: Match the part number exactly. While Subaru and Toyota parts are often interchangeable on this platform, it's safest to match your original part number (87611CC001 for Subaru, SU00308762 for Toyota).
• Inspect for Physical Damage: Look for cracks in the black plastic housing. Any crack can allow water inside, which will destroy the delicate electronics. This is a primary cause of failure.
• Check the Connector: The electrical connector pins should be clean, straight, and free of any green or white corrosion. Corrosion indicates water intrusion and the part should be considered faulty.
• Ask About the Donor Vehicle: If possible, find out the history of the car it came from. A sensor from a low-mileage, non-accident vehicle is always preferable. A sensor from a car with a rear-end collision is a major red flag.

Replacement and Calibration

Replacing the sensor is a multi-step process that requires both mechanical work and specialized electronic calibration.

1. Mechanical Installation: The rear bumper cover must be removed to access the sensor. The sensor itself is typically held by a few bolts to a bracket on the vehicle's body. While unbolting the old sensor and bolting on the new one is straightforward, the bumper removal adds significant time and complexity.

2. ADAS Calibration (Required): This is the most critical and difficult part of the job. A new or used sensor cannot simply be installed and expected to work. The system must be calibrated by a qualified technician using specialized equipment. This process involves:

• Connecting a diagnostic tool (like Toyota's Techstream) to the vehicle.
• Placing specific radar reflectors or targets at precise, measured distances and angles behind the vehicle.
• Running the calibration utility in the software, which tells the sensor how to aim itself and interpret the radar signals correctly for your specific car.

Frequently Asked Questions