Reader's Choice: Blind Spot Monitoring - BodyShop Business

Reader’s Choice: Blind Spot Monitoring

"Many cars such as Toyota and Lexus are offering blind spot monitoring, and there are four sensors on each car behind the bumper covers. I've heard that if the paint on the bumper cover is too thick or has filler, the sensors won't function properly. Is this true?"

For 15 years, BodyShop Business has been giving readers a chance to win a cool $50
by submitting questions on a collision industry topic of their choice.
This year, three lucky individuals were selected to have an expert
answer their question. John Borek was one of those lucky readers, and
his question is below.

“Many cars such as Toyota and Lexus are offering blind spot monitoring. There are four sensors on each car behind the bumper covers. I’ve heard that if the paint on the bumper cover is too thick or has filler, the sensors won’t function properly. Is this true? And how would you test them after a repair?”

— John Borek, general manager, Autocraft Bodywerks, Austin, Texas

Question answered by: Karl Kirschenman

When you’re trying to move a car through your shop, the smallest details can trip you up and throw a monkey wrench into your repair plan. Especially annoying are the issues that come at you from left field – the unforeseen factors that make you scratch your head and go, “Huh?”

Vehicles today are increasingly loaded with many new features that are making the roads a safer place. But all these new technologies also increase the challenges for collision shops. Every OE system is unique with its own special quirks.

Blind spot monitoring systems are a real-life example. Some systems use cameras. The Toyota/Lexus system relies on millimeter wave radar sensors installed behind the rear bumper cover. The system detects vehicles entering the driver’s blind spot on either side and illuminates an indicator in the sideview mirror. If the driver signals a turn, the indicator flashes. However, millimeter wave technology does have some inherent problems. The waves can be absorbed by gases in the atmosphere, limiting their range. Rain in particular, and humidity in general, can also diminish the signal strength.

In addition to these limitations, the system can’t detect what it can’t “see.” There can be nothing impeding the sensors. Think of looking through glasses with badly smudged lenses – you get the idea. Anything blocking the radar will impair its performance – ice, mud, snow and especially a fresh coat of paint!

Suppose that you have just worked on a Toyota or Lexus with the OE-installed blind spot monitoring feature. There was damage to the bumper, but you did your usual superb job and the car looks like new. You even took care of a tiny scratch on the blind spot sensor. The paint match is perfect and the bumper looks like new. The owner drives away happy.

So why is he driving back to your shop a few days later telling you that the blind spot system no longer works? You know you did your job right, so what’s the problem?

Here is a portion of what Toyota says about repair involving its blind spot monitoring system. Take special note of items (5) and (6).

Handling the Radar Sensor
One blind spot monitor sensor is installed inside the left and right sides of the vehicle’s rear bumper, respectively. Observe the following to ensure that the blind spot monitor can function correctly:

  1. Keep the sensor and its surrounding area on the bumper clean at all times.
  2. Do not subject surrounding area of the bumper to a strong impact. If the sensor moves even slightly off position, the system may malfunction and vehicles that enter the detection area may not be detected. If the surrounding area has been subjected to a strong impact, inspect the sensor and surrounding area.
  3. Do not disassemble the sensor.
  4. Do not attach accessories or stickers to the sensor or surrounding area on the bumper.
  5. Do not modify the sensor or surrounding area on the bumper.
  6. Do not paint the sensor or the surrounding area.
  7. Do not apply strong impacts to the sensor or drop it, as it is a high-precision device.
  8. Do not reuse a sensor that has been dropped or subjected to a strong impact.

Karl Kirschenman, ALLDATA collision product manager, holds a bachelor of science degree in communication. He has more than 10 years of experience in the collision industry.

© 2014 ALLDATA LLC. All rights reserved. All technical information, images and specifications are from ALLDATA Collision S3500. ALLDATA and ALLDATA Collision are registered trademarks of ALLDATA LLC. Toyota and Lexus are registered trademarks of Toyota Motor Corporation and/or Toyota Motor Sales, U.S.A. All other marks are the property of their respective holders.

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