ADAS - Plastic is deceptive

Nelson Manager California Posted   Latest  
Case Study
Autonomous Vehicles
2019 BMW 750Li xDrive 4.4L (N63B44B) 8-spd (GA8HP75Z)
48214A - Acc Sensor/Frsf : Lack Of Visibility


Since most production vehicles out in the world have radar sensors that are exposed to damage, this is a great case study for all brands. 

This vehicle was a 2019 BMW 750Li (G12) and came into the shop because the front ACC (Cruise Control Sensor) was inoperative. A rock had hit the front ACC heater cover but the sensor itself did not look damaged. 

The vehicle had a fault code for lack of visibility by the ACC cruise control sensor.

The technician replaced the broken ACC sensor heater cover and ACC sensor bracket (bracket did not look damaged). (FYI the sensor is $2500)


Here is a photo of the calibration technique for this vehicle and tools. (obviously not a G12)


Here is a photo of the sensor.


The vehicle was setup for ACC radar calibration and failed. 


After updating the i-level of the vehicle and triple checking all ACC calibration measurements, the decision was made to open up the radar sensor. 

This is what was found. 


Even though there wasn’t any damage to the plastic casing of the ACC sensor, the plastic did bow which damaged the VERY soft gold metal behind it. The plastic bowed back and looked like nothing had happened.

The ACC sensor was replaced, programmed, and the ACC sensor ADAS calibration was performed again. The vehicle was fixed.

NOTE: Front radar cruise sensors and blind spot sensor are extremely prone to damage if dropped, hit, etc. 


Joel Diagnostician
Joel Default

Wss it require complete calibration of the system or only sensors/ radar involved? How long does it take the calibration? how much does it cost this process for adas system?

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Nelson Manager
Nelson Default

Just the front radar sensor needed calibration. The calibration could be done in less than an hour. Like with anything, depends on experience. Customer pay price is 2 to 4 hours × labor rate, depending on where you go.

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Rex Technical Support Specialist
Rex Default

Does the gold piece function as an antenna or perhaps emitter? I am curious why the deformation affected it. Great find.

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Marlin Technician
Marlin Default

Excellent post, thank you! I KNOW that people are going to try to repair such problems, and aftermarket replacements will enter the market. These issues will make diagnosis exceedingly more difficult.

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Joel Diagnostician
Joel Default

thank you

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Anthony Technical Support Specialist
Anthony Default

Hi Nelson: A came across something today which appears in the future to make the issue you described much more common. sae​.​org/news/2019/10/r… Soon, you'll get two (or more) issues for the price of one. Guido

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James Technician
James Default

Great link on the materials article, solid state Lidar is certainly appealing. For us Calibration Tech's there is a thought, if everyone is driving around with a hockey puck on the roof of the car work may dry up quickly. So I'm glad to see they some are looking away from electro-mechanical configurations. I really think everyone wins at that point as blind spot areas are certainly much larger…

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Jimmy Analyst
Jimmy Default

Could I use this case study in a textbook I'm doing on research on (for the author)? Could you email me at …

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