2017-2025 Honda Ridgeline Blind Spot Radar: Solving the 'BSI System Problem' Warning

Symptoms of a Failing Blind Spot Module

When a blind spot radar module begins to fail, the symptoms are usually very clear and consistent. The location of the modules behind the rear bumper makes them susceptible to damage from minor impacts, road debris, and water intrusion.

• "Blind Spot Information System Problem" Message: This is the most common symptom. A warning message will appear on the Multi-Information Display (MID) in the instrument cluster. This message indicates the system has detected a fault and has been disabled.
• Intermittent Operation: Many owners report that the warning message appears intermittently, especially after the truck has been sitting in direct sunlight or during hot weather. The system may reset and work normally after the vehicle cools down, only to fail again later.
• Warning Lights Do Not Illuminate: The amber warning lights on the interior A-pillars will not light up when a car is in your blind spot, as the entire system is shut down.

Diagnosing the Problem

While the dashboard message points directly to the BSI system, a few steps can help confirm the issue before buying parts.

1. Check the Bumper: Inspect the corners of the rear bumper for any signs of physical damage, however minor. A small impact can be enough to knock a sensor out of alignment or damage its internal components.
2. Clean the Area: Thoroughly wash the rear bumper corners. Heavy dirt, mud, snow, or ice can sometimes obstruct the radar's signal and cause a temporary error.
3. Read Fault Codes: The most definitive way to diagnose the issue is to have the fault codes read with a Honda-compatible diagnostic scan tool. The system will store a Diagnostic Trouble Code (DTC) that specifically identifies which side (left or right) has failed and the nature of the fault (e.g., open circuit, internal failure, or alignment issue). This step is crucial to ensure you replace the correct module.

Buying a Used Blind Spot Module: A Buyer's Guide

Given the high cost of a new OEM module, a quality used OEM part is an excellent value. However, there are important factors to consider when buying used.

Why Choose a Used OEM Module?

For a sensitive electronic component like a radar module, a used Original Equipment Manufacturer (OEM) part is often a better choice than a new aftermarket one (which are not commonly available for this part anyway). OEM modules are built to Honda's exact specifications for performance and durability. A used OEM part that has been tested and is in good condition will integrate with your vehicle's systems correctly, which is critical for the mandatory calibration process.

What to Inspect Before Buying

• Physical Condition: Examine the module's casing for any cracks, deep scratches, or signs of being opened. Pay close attention to the connector pins—they should be straight, clean, and free of any corrosion.
• Part Number Verification: This is the most critical step. Match the part number exactly. The primary part number for the 2017-2025 Ridgeline right (passenger) side is 36931-T6Z-A12. This part supersedes 36931-T6Z-A11. You may also see it listed under part number 36930-T6Z-A02. Ensure the part you are buying is one of these numbers for the right side. The left side module is a different part number (36936-T6Z-A12) and will not work.
• Source and Warranty: Purchase from a reputable seller that offers a warranty. A warranty provides protection in case the used module is faulty.

Replacement and Calibration Guide

Replacing the blind spot module involves two distinct phases: physical installation and electronic calibration.

Installation Difficulty: 4 out of 5

The physical installation requires removing the rear bumper cover to access the module, which is bolted to the vehicle's body. While this is manageable for an experienced DIYer, the mandatory calibration that follows requires specialized equipment, making this a job best left to a professional shop or a dealer.

Installation Overview

1. Disconnect the vehicle's battery.
2. Carefully remove the rear bumper cover. This typically involves removing screws in the wheel wells, clips underneath, and bolts near the tailgate.
3. Locate the faulty module on the rear corner of the body.
4. Disconnect the electrical connector and unbolt the module from its bracket.
5. Install the new module, ensuring it is seated correctly on its mounting bracket.
6. Reconnect the electrical connector and reinstall the bumper cover.

The Critical Calibration Step

BSI radar calibration is a precise procedure that tells the vehicle's computer the exact angle and position of the new module. This ensures the radar is looking in the correct zone. This process requires:

• A compatible, high-level diagnostic scan tool (like the Honda HDS or a professional Autel/Snap-on unit).
• Specialized radar calibration targets and stands.
• A large, level workspace.

A qualified independent auto shop specializing in ADAS (Advanced Driver-Assistance Systems) or a Honda dealership can perform this calibration.

Known Issues, Recalls, and TSBs

As of mid-2026, there are no official recalls or Technical Service Bulletins (TSBs) from Honda specifically for the failure of the BSI radar modules on the 2017-2025 Ridgeline. However, the issue is widely documented by owners in online forums. The failures appear to be treated by Honda as individual component faults covered under the vehicle's warranty, rather than a systemic defect requiring a recall campaign. Other recalls exist for this generation of Ridgeline, such as for the rearview camera wiring harness, but these are unrelated to the BSI system modules.

Cost Comparison

Frequently Asked Questions (FAQ)