Question on sensors

[Cobra348]

While heading to Rochester last week, I was subjected to a wet, slushy snow coming directly at me face-on. I was running ACC at a bit under limit and things were fine until >DING!< "Adaptive Cruise Control inoperative. Sensors are blocked. See manual." and I drop out of cruise - back to manual.

 

When I did get a chance to pull off the road and check ... sure enough the two sensors bracketing the front license area were crusted over quite well. So, I have a question ...

 

Is there anything I can use on these to prevent slush/snow buildup like this and yet allow the sensors to operate correctly? I'm thinking perhaps petroleum jelly (Vaseline or the like). Will/does/can this work? I also realize if yes it will need refreshing after a wash or just after a period of time.

 

Sooooo, anyone got an answer for me - or should I enter the "bleeding edge of experimentation"? ;)

 

 

 

[murphy]

Adaptive cruise control uses radar, not the ultrasonic parking sensors. The radar unit is in the driver's side of the grill on my 2013. It also might use the camera but the windshield wipers should keep that clear.

[Texasota]

Interesting question and one that manufactures will have to figure out before fully autonomous cars become a reality.

[Cobra348]

Adaptive cruise control uses radar, not the ultrasonic parking sensors. The radar unit is in the driver's side of the grill on my 2013. It also might use the camera but the windshield wipers should keep that clear.

Then how come I pull over, clean off the gunk ... hop back in car and restart it with no ACC error message and good operation? It may be there is a camera, but **something** is telling ACC the distance to the vehicle ahead. And it HAD to be the bumper sensors because the windshield was clear and unobstructed.

 

Guess it's off to the dealer and some tech talk if possible.

Edited November 1, 2016 by Cobra348

[hermans]

Then how come I pull over, clean off the gunk ... hop back in car and restart it with no ACC error message and good operation? It may be there is a camera, but **something** is telling ACC the distance to the vehicle ahead. And it HAD to be the bumper sensors because the windshield was clear and unobstructed.

 

Guess it's off to the dealer and some tech talk if possible.

It is a radar and like murphy said it's on the right side of the grill (as you face it) behind the plastic covering. What you experienced is normal and is covered in your manual. When you clear the plastic area it works again. The owners manual is your friend. The acc radar is in the same place on all of my Ford/Lincoln vehicles.

[Cobra348]

I did NOT clear any grille areas - upper or lower. I only cleared accumulation from the buttons within the bumper faschia. The grilles were actually in very good shape and also unobstructed.

[murphy]

If ACC shuts down for any reason the procedure to get it reactivated is to park the car and shut it off. I have had it shut down as a result of heavy rain at 55 mph.

[Waldo]

Yup, it was the shutting down and restarting that cleared it up. The system has an algorithm in it that basically figures out when it's getting too much input to make sense, whether it's because it's seeing a thick wall of something in front of it or just too much radar noise from all the heavy snow/spray in the air. I've had it shut down it heavy rain when there's a lot of spray coming off the road. No amount of vaseline is going to prevent that.

 

Bottom line is that if the spray/snow is thick enough to trip out the radar, you really shouldn't be using cruise control anyway.

[tr7driver]

I'd be careful using any cruise control in that kind of weather. I increases the odds of the car skidding out of control if the wheels break traction.

[Cobra348]

this was first flurry action of the season ... roads were wet with accumulation on grass, gas pumps, my front faschia and the like. Was all melted off by afternoon.

 

agree on ACC usage in lousy weather like that though.

Edited November 1, 2016 by Cobra348

[md13ffhguy]

It's definitely not those buttons on the bumper fascia, since my car has ACC, but no buttons...

[Cobra348]

Well, I asked at the dealer. Sales guy has 20+ years Ford - fleet and consumer - with an electronics degree. Knows how the ACC works. Also talked with a service tech who actually does the work on vehicles needing it. Here's how it works - in general. Remember, this is ACC with Stop/Go Technology - a '17 FFH. So the implementation may be different from prior years.

 

ACC is essentially a radar (or sonar) system that has a gun (transmitter) and receivers (sensors). The gun is behind the grille blocker in the upper grille area. The front faschia has 4 sensors - 2 outboard near the corner and 2 inboard bracketing the license area.

 

The front sensors comprise the collision warning system, proximity warning when parking and receivers for ACC. Probably other stuff as well. The inboard sensors are the ACC receivers in addition to other duties. In my original post, it was these that were crudded up with snow/slush pack - and that prevented the signal from getting received. Thus the error message I got. Simple stop/start of the car would not have fixed the issue but the cleanoff did.

 

What can be used to prevent or alleviate heavy build-up like that? A good coat of wax is all any of us can come up with. So I'll get some Rain-X stuff and have it handy to see if it helps. <shrug>

Edited November 6, 2016 by Cobra348

[murphy]

The radar transmitter and receiver (77 GHz) are in the same unit. They have a range of about 500 feet. The four round units on the front are ultrasonic transducers (transmit and receive). They have a range of about 15 to 20 feet. (Sonar is on submarines and only works under water.)

 

http://cache.nxp.com/files/microcontrollers/doc/fact_sheet/AUTORADARFS.pdf

[Cobra348]

Huh. Not what I was led to believe ... I'm gonna print this puppy out and see what they say. So I am back to one of the questions ... Is this the underlying ACC tech for sure? Ford wouldn't have something else than this?

 

If - as you say - the transmitter and receiver are same unit - AND it is behind the grille blocker, then why is it that there was no blockage at that area and ACC was inop. However once I cleaned those faschia units, ACC was operative?

Edited November 7, 2016 by Cobra348

[murphy]

ACC uses radar and possibly the Mobileye camera although the camera is mainly for lane holding.

 

I have had ACC shut down due to heavy rain being thrown up from the tires of the car in front of me. Once it turns off it stays off until the car is put in park and turned off.

[hermans]

I have driven a Fusion with ACC and it didn't have lane keeping. I do believe it solely radar.

[Waldo]

In the 2017+ Fusion with the start/stop system, the camera is used to supplement the info from the radar. In the early gen system it is not. The front park aid sensors are just that, park aid sensors. They don't have anything to do with ACC.

As I said above, the reason your system shut down was due to the heavy spray. When you started up the car again it didn't detect any spray, so it decided it was ok to work again.

[hermans]

Good to know. All of my experiences with ACC have been in earlier.