[Sean Nelson]

This is what it looks like on my Bolt, which was built in mid-September 2017:

The only foil I can see is a triangle-shaped piece on the very bottom of the sensor unit. Seems to work perfectly.

 

[ribbitribbit]

This is what it looks like on my Bolt, which was built in mid-September 2017:

The only foil I can see is a triangle-shaped piece on the very bottom of the sensor unit. Seems to work perfectly.

Yeah that's the foil. See how it's just a small sliver of the tape that attaches to the side of the rear fascia? On my bolt, on the passenger side, that had become detached. Re-attaching it solved the problem of the passenger-side SBZA picking up stuff that wasn't there. Then I went ahead and added some more aluminum tape for good measure, so it will STAY that way.

 

[bao123]

I think I have the same problem as yours. I sent my vehicle to a dealership and they couldn't figure it out. We scheduled another appointment to follow up. What would be the best way I can help them to get this fixed?

Should I just tell them that we should add "aluminum butyl tape" to "the bottom of both left and right object sensing alert module bracket"?

Add me to the list,

I thought it was related to my Winter Tire Setup as it appeared right after I swapped wheels/tires. Seemed the SBZA only was an issue with the Passenger side of the car however.
The new wheels tire setup stick out 1/4". So is the Sensor that Sensitive?

I tried a variety of things troubleshooting, the problem seemed to go away by swapping back to my Original tires/ wheels. So in know the sensors worked OK.
However put the Winter tires on and the SBZA would trip.

This was driving me nuts and I had to get to the bottom of why the sensor was tripping constantly.

Eventually I thought it had to do with weight in the rear and angles as I noticed when loaded up in the back the sensor was off.
Chasing my tail here......
http://www.chevybolt.org/forum/12-w...-sonic-16-s-205-xice3-s-using-quick-jack.html

However a few days later it came back again, Regardless of weight in the back. Throw that theory out the window.

Then I realized the days it was working normally with the winter wheel/tires it was raining.

So sure enough on sunny days the SBZA passenger light was on constantly.

So I experimented some more by soaking the rear wheel well down and yes the problem went away.
I tried this 3 days in a row and could verify it would work normally if the wheel well was wet. As soon as it was dry again it would trip the SBZA passenger side sensor....

Crazy right? Believe me I know...

So was water on the wheel well blocking/deflecting the radar signal enough for the system to work normally!???

The Only TBS that seems to be related is below....

17-NA-097 Side Blind Zone Issues or False/Incorrect Side Mirror Notification/Warnings

NOTE: This bulletin ONLY applies to 2017 Bolts equipped with Side Active Safety Obstacle Detection Enhanced (RPO UKC)

NOTE: This condition may potentially be experienced after rear fascia removal/reinstallation or rear fascia replacement.

Condition/Concern- Some customers may comment when driving, the side mirror indicates there is a vehicle present when there actually is not

Root Cause- This condition may be due to missing aluminum butyl tape that is located on the bottom of both left and right object sensing alert module bracket. This tape is important to the performance of the module object sensing.

Corrective measures- Install specialized aluminum butyl tape patches on the bottom of the object sensing alert module brackets. Use PN# 42563361 (LH) and 42563362 (RH)

*******************
WOT

Both of mine however looked OK

So I decided to add a bit more around the side of the sensor toward the wheel well. I took a bit of foam and wrapped it with some Foil tap and placed it up there.

It seems to work. I drove around and tested with traffic, and the system works normally for me. No false readings, no constant SBZA light on the passenger side.
I'll keep an Eye on it....

I'd like to hear from those who took the car in for service if there truly was a software patch ( to change the angle or sensitivity of the sensors) and if they added more foam tape.

 

[bao123]

Where did you find that sensor? Do you mind taking an overview picture of this car and point out where this is?
Thanks!

@;

This is what it looks like on my Bolt, which was built in mid-September 2017:

The only foil I can see is a triangle-shaped piece on the very bottom of the sensor unit. Seems to work perfectly.

 

[Sean Nelson]

Where did you find that sensor? Do you mind taking an overview picture of this car and point out where this is?

The sensor is behind the corner of the bumper at approximately this location:

 

[bbg523]

Start with adding foil to the side of the sensor closest to the wheel well, on both sides and see if that takes care of it. You can actually just wrap the complete back side of the sensor this will deflect any stray signals. I wound up doing this and have had no issues since.

 

[Eriamjh1138]

Here's more information about the SBZA radar units:

The radar unit is behind the facia with a small air gap. 40% of the signal sent out is reflected directly back and passes through the sensor (ignored because it's too close). On the Bolt, this reflection bounces off the body, hits the wheel, then back to the body and to the sensor where it is detected.

Because radar is time-based for distance detection, the bounced signal is detected as an object about 3-4 feet away from the car and this triggers the SBZA light. In addition, the spokes of the factory wheel cause a pulsing of the signal, which further confuses the sensor into thinking there is an object in the zone.

A change of the rear wheels can be falsely detected as an object because the sensor with the alumininium butyl-foil shield, and the factory wheels are all calibrated around the shape of the signal. Change the wheels, change the signal = false alert.

The solution is simple, but for GM it was expensive: A proper shield behind the radar will block the secondary reflection. However, the shield cost, mounting method, and retention tests (bumper impact) have left us with an adequate, but inferior solution (butyl foil tape). So if you want a permanent solution, fabricate a metal shield that can mount directly behind the sensor. I'm not sure is its mounting angle is important (like reflect away from the sensor), so it's up to you.

 

[SanFranTanguero]

Thanks for all the details. This problem just started showing up in my 4/17 Bolt. Would you mind showing a photo of the ‘finished product ‘, i.e. what it looks like once you wrapped it? By the way, it just showed up randomly; no tire changes or anything that I’ve done to the car.
Thanks, SFT

 

[SanFranTanguero]

Thanks to the postings here, I discovered the root cause of the false blind side alerts. I went out to the garage to determine if I could get underneath the bumper to identify the sensor. As I closely looked at my bumper, I found that some jerk had hit my car and slightly dinged the bumper (and didn't leave a note). It's the imperfection in the bumper that is giving the false readings. I am sure I would not have noticed the ding for a long time had I not been scrutinizing the location of the sensor. There is a visible distortion of the bumper and apparently enough to set off the false positives. As the damage is so visibly minor that if I can use the metal tape method to address the problem, I will. If the tape doesn't work, it's off to the repair shop to see what they can do and the cost :-(

But now you know that a small ding in the bumper can cause this kind of problem. As our cars get more computerized and 'smarter' there's a whole new set issues.

 

[beeguz]

But now you know that a small ding in the bumper can cause this kind of problem. As our cars get more computerized and 'smarter' there's a whole new set issues.



I guess that is why you see so many seemingly slightly damaged Tesla cars totaled, they have sensors everywhere.

 

[SanFranTanguero]

SBZ false alarms fixed and accurate alarms now working.

The slight damage from someone hitting my bumper in a parking lot loosened the foil and the radar unit (ever so slightly). So, in the hopes of a permanent fix, I first cleaned the plastic interior of the bumper (with a non-ammonia glass cleaner) where I intended to put the metal tape. Then I did a first pass of taping to see if I was on the right track and, indeed after driving in the slow lane where cars were passing frequently, it looks like the unit is behaving as it did in the past and is now working. It's hard to say if it's working EXACTLY like it did in the past as I don't really have a benchmark, however, it no longer is giving false SBZ alerts and is correctly identifying when a vehicle is the the SB zone. After verifying that the fix worked, I went back to add some more tape to hopefully make the fix a bit more permanent through better adhesion to the radar unit and the interior of the plastic bumper.

So, hopefully that ends my saga for years to come. I'm pleased because I am sure if I had taken the car into the service department, they would have replaced the bumper which would have been costly. Not sure if they would have replaced all the interior sensors in the bumper as well, but that would have added significantly to the cost of materials and labor.
Thanks

 

[Sean Nelson]

SBZ false alarms fixed and accurate alarms now working.

Good job, thanks for sharing!

Where did you get the metal tape?

 

[SanFranTanguero]

The metal tape is (search on Google) "metal duct tape". I actually don't know exactly its providence because I was given about 3 feet from a friend who had a large roll of it. I did feel that it should do the trick because such tape is designed to last for many years on an HVAC system which typically is vibrating and has temperature changes, so it should survive being used on an vehicle. So while the adhesion is critically important, so is the metal which is shielding the radar signal, but I'd guess that any good quality metal tape should do the trick. The good news is that the tape is a heck of a lot more affordable than a new bumper!

 

[bbg523]

SBZ false alarms fixed and accurate alarms now working.

The slight damage from someone hitting my bumper in a parking lot loosened the foil and the radar unit (ever so slightly). So, in the hopes of a permanent fix, I first cleaned the plastic interior of the bumper (with a non-ammonia glass cleaner) where I intended to put the metal tape. Then I did a first pass of taping to see if I was on the right track and, indeed after driving in the slow lane where cars were passing frequently, it looks like the unit is behaving as it did in the past and is now working. It's hard to say if it's working EXACTLY like it did in the past as I don't really have a benchmark, however, it no longer is giving false SBZ alerts and is correctly identifying when a vehicle is the the SB zone. After verifying that the fix worked, I went back to add some more tape to hopefully make the fix a bit more permanent through better adhesion to the radar unit and the interior of the plastic bumper.

So, hopefully that ends my saga for years to come. I'm pleased because I am sure if I had taken the car into the service department, they would have replaced the bumper which would have been costly. Not sure if they would have replaced all the interior sensors in the bumper as well, but that would have added significantly to the cost of materials and labor.
Thanks

Glad to hear this worked for you as well! I can tell you I still have no issues after many miles with the the fix, SBZA works as it should.

 

[lexcyn]

Thanks all in this thread - I had this issue after getting winter tires put on (put them on stock rims too). Drivers side would be "stuck" on after a car passed and passenger side wouldn't really come on at all.

Ended up using the aluminum duct tape around the factory foam/metal adhesive on both sides and it seems to have fixed it completely. I had to adjust the drivers side a few times but eventually got it working.

 

[Chwkev]

We started having intermittent erroneous SBZAs. We booked the car in at the dealer and they checked for the latest firmware update (which it already had) and when that was good they said the next step was to check all the connections in the SBZA system (expose all the connectors, unplug and reconnect them and reapplying the dielectric grease to the connectors). Shortly after they started this process (I think they started at the back near the sensors) the said that they discovered the butyl foil pieces that go over the sensors were coming detached and needed to be replaced. They ordered the patches (which arrived the next day), booked the car in again and had the butyl foil replaced. So far so good. No false alerts yet.

 

[Chwkev]

Update: still having random false alerts from SBZA. We will be booking it back in to the dealer to have them continue looking at it.

 

[max]

Update: still having random false alerts from SBZA. We will be booking it back in to the dealer to have them continue looking at it.

Most common issue seems to be around metalic tape in the rear bumper.
If it was not applied correctly, or is peeling off. Others have fixed themselves but dealer should be able to as well.

 

[Chwkev]

Most common issue seems to be around metalic tape in the rear bumper.
If it was not applied correctly, or is peeling off. Others have fixed themselves but dealer should be able to as well.

Just had it in to the dealer last month and they applied new tape to the sensors.

 

[LectricBill]

I recently changed my wheels and tires and, sure enough, have the Intermittent Side Mirror Alert Syndrome.
I don't want to go to the super-spreader dealer waiting room, and intend to fix this issue myself.
Before I glom rolls of aluminum duct tape over the whole inside of my bumper, I have a couple of questions:

1) What is the purpose of using foam? Wouldn't the aluminum tape by itself block the signals?

2) Some have used the tape only at the edges of the OEM shield. Others advocate covering the entire back of the radar unit.
While covering the back of the unit makes sense to me (if the goal is to block rearward propagation), might doing so mess with the unit's algorithms that are processing the delay time of the return signals and have been calibrated for the OEM shield placement? Has anyone just put tape on the back of the radar unit and around its edges and had that fix work?

Many thanks to those who have figured this out. Someday GM may come up with a more elegant solution, one that will allow owners to change types of wheels/tires.