2010-2018 Acura MDX Blind Spot Sensor: Solving the 'Check System' Warning

Generational Differences: 2010-2013 vs. 2014-2018 MDX

The 2010-2018 Acura MDX spans two distinct vehicle generations, and the blind spot sensors are not interchangeable between them. It is crucial to identify your vehicle's generation before purchasing a replacement part.

• Second Generation (2010-2013): These models use a single part number, 36931-STX-A02, for both the left (driver) and right (passenger) sides. The sensor is located behind the rear bumper cover in the corners.
• Third Generation (2014-2018): These models use different part numbers for the left and right sides. The sensors are also located in the rear corners. Common part numbers include 36930-TZ5-A11, 36931-TZ5-A02 (Right/Passenger Side), and 36931-TZ5-A21 (Right/Passenger Side). Always verify the exact part number for your specific year and side, as there are several revisions.

Common Symptoms of Failure

When a blind spot sensor fails, your vehicle will typically alert you in several ways. The most common sign is a warning message on the Multi-Information Display (MID) in your instrument cluster.

• "Check Blind Spot Information System" Message: This is the most direct indicator that the vehicle's computer has detected a fault within the BSI system.
• System Inoperative: The blind spot warning lights near the side mirrors will not illuminate when cars are in your blind spot. The system simply stops working, sometimes without an initial warning message.
• Multiple Warning Lights: On some MDX models, a failing blind spot sensor can cause a cascade of other warning lights to appear, including for the transmission, emissions system, or parking brake. This happens because various safety systems are interconnected.
• System Turns On But Doesn't Work: In some cases, the system may indicate that it is active in the vehicle's settings menu, but it will not actually detect vehicles or provide warnings.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

While there are no specific recalls for the blind spot sensors themselves on the 2010-2018 MDX, there are related issues and recalls for this vehicle generation that owners should be aware of.

• Moisture Intrusion: A common cause of failure is water getting into the sensor. For 2014-2020 models, Acura issued a recall and TSB (25-001) for moisture entering the inner taillights due to a bad seal. While this recall is for the lights, it highlights the potential for water intrusion issues in the rear of the vehicle which can also affect nearby radar sensors.
• Rear Subframe Corrosion: Honda issued a recall for 2014-2020 MDX vehicles sold in states that use road salt, due to premature corrosion of the rear subframe. Severe corrosion in this area could potentially affect the sensor's mounting bracket or wiring.
• Blocked Sensors: The owner's manual notes that heavy dirt, snow, or mud on the rear bumper corners can obstruct the radar signal and cause the system to temporarily stop working. Always ensure this area is clean before assuming the sensor has failed.

Buying a Used Blind Spot Sensor

Purchasing a used OEM sensor is a cost-effective way to restore your BSI system. Because these are sensitive electronic components, careful inspection is key.

1. Verify the Part Number: This is the most critical step. Match the part number from your old sensor exactly. As noted, 'STX' parts are for 2010-2013 models and 'TZ5' parts are for 2014-2018 models. Within the 2014-2018 range, ensure you have the correct part for the driver or passenger side.
2. Inspect the Housing: Look for any cracks, chips, or signs of damage to the black plastic housing. A compromised housing can allow moisture to enter and destroy the internal electronics.
3. Check the Connector: Examine the electrical connector pins. They should be straight, clean, and free of any green or white corrosion. Corroded pins indicate moisture damage and the part should be rejected.
4. Ask About the Source Vehicle: If possible, find out if the vehicle the part came from had any rear-end collision damage. Even a minor impact can damage these sensitive radar units.
5. Choose OEM Over Aftermarket: For complex safety components like radar sensors, used OEM parts are generally more reliable than new, inexpensive aftermarket alternatives. The OEM parts are designed to meet Acura's specific calibration and performance standards.

Installation and Calibration

Replacing the sensor is a moderately difficult job that most experienced DIYers can handle. However, the need for professional calibration adds a layer of complexity.

General Replacement Steps:

1. Disconnect the vehicle's battery.
2. Carefully remove the rear bumper cover. This usually involves removing screws in the wheel wells, plastic clips underneath, and bolts inside the trunk area.
3. Locate the failed sensor mounted to the vehicle's body or a bracket in the rear corner.
4. Disconnect the electrical harness and unbolt the sensor from its mounting bracket.
5. Install the new sensor, ensuring it is seated correctly on its bracket.
6. Reconnect the electrical harness, reinstall the bumper cover, and reconnect the battery.

Cost of Replacement

The cost to replace an Acura MDX blind spot sensor can vary significantly based on the parts you choose and who performs the labor.

Note: Labor costs for installation and calibration are separate. Total shop replacement cost can range from $966 to over $1,500 depending on the parts used.

Frequently Asked Questions (FAQ)