Need help with BSM. BSM error light flashing

up4speed

Member
This problem is driving me nuts! I have an intermittent problem with my drivers side BSM not working every now and then on my '08 CX-9 GT.
After the drivers side not working for a few minutes, it triggers a flashing "BSM Off" light. Sometimes it will work perfectly, other times not.
When hooked up to a diagnostic computer to read DTC's and history codes, nothing comes up unless the BSM is actively flashing (no history codes). So I hooked it up to my friends computer while it flashed and got code: U3000:97-8A. According to research that I've done, it all pointed to a messed up signal in the Left BSM module, usually caused by dirt, or physical damage. I checked everything and it was all good, so the last thing on the list was a defective module. I ordered and installed a replacement, now it doesn't work at all! (on the drivers side, passenger side works still) and of course after a few miles of not working, the flashing "BSM Off" light illuminates. I pulled the code and it is the same code as before I replaced the module.
Does anyone have any idea what could be wrong? Is it just that the new module needs to be "set up" or "calibrated"? Is it normal to not work at all after a replacement?
As of now, I have no idea what to do so I made an appointment at the dealer for this Thursday hoping that they just need to do a calibration on it.
Any ideas?
 
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I just got back from the dealer.
They were unable to program the replacement module. They told me that I have to change BOTH modules (left and right) at the same time. I don't know why they don't only sell them in pairs then, nor do I know how they know that they are together when ordered, but apparently nobody knows why, they just say that it works. The modules are very expensive (~$625 each) so I don't now what to do at this point. I'm also assuming that I have to pay again to have them programmed to the car, so there goes another $100. Then I have to question, what if it's something else? I wonder if it can be the body control module? I'm very frustrated at this point.
I was even willing to pull the BSM OFF light bulb out and to hell with the whole BSM, but I don't think it's even a bulb, I think it's the whole cluster as a unit, so I can't even do that!!!
Any suggestions?
 
I gave up and ordered the left and the right blind spot monitors. They should be in on Saturday, I'll report back after I install them.
 
Final update:
I installed two brand new blind spot monitors on the right and left today. It was very easy to remove the bumper and replace them. I'm happy to report that after replacing BOTH, the system is now working flawlessly, and there was no programming required! The only downside is that the parts came out to $1,152.
(I had a fun time talking to myself on this thread, LOL)
 
Final update:
I installed two brand new blind spot monitors on the right and left today. It was very easy to remove the bumper and replace them. I'm happy to report that after replacing BOTH, the system is now working flawlessly, and there was no programming required! The only downside is that the parts came out to $1,152.
(I had a fun time talking to myself on this thread, LOL)
Was that the price for all parts? Or just the two purchase together?
 
Final update:
I installed two brand new blind spot monitors on the right and left today. It was very easy to remove the bumper and replace them. I'm happy to report that after replacing BOTH, the system is now working flawlessly, and there was no programming required! The only downside is that the parts came out to $1,152.
(I had a fun time talking to myself on this thread, LOL)

Sorry to hear about the troubles and glad you got it worked out. Actually, your experience here with these sensors - and the cost - is a very timely example of why I'm changing my opinion on extended warranty for the bumper2bumper. We keep cars for the long term, and the dealer is including lifetime coverage on power-train. That is a nice plus, but in light of the amount of computer/electronic components & systems in the current generation of cars, the likelihood of a simple but pricey failure occurring in that ecosystem appears to be a risk that changes the calculation for extending that coverage. The dealer will be presenting us with some options and quotes when we pick up the new Silver Sig this week; I am strongly considering adding that coverage.
 
Was that the price for all parts? Or just the two purchase together?

The original monitor I purchased was used and it didn't work (probably because I needed to change both left and right), it cost $250, but I'm able to return it, so no loss there. The 2 new ones that I bought came with new brackets and wiring harnesses and list price for them was about $625 each. I was able to get a discount for the new sensors, so the total after taxes was $1,152. I installed them myself, they were pretty easy. The only other cost was the trip to the dealer trying to program the first used module for it to work. That was about $70. So all in, I'm at about $1,230.
I can also sell my used (good side) monitor on ebay and recoup about $200.
 
Sorry to hear about the troubles and glad you got it worked out. Actually, your experience here with these sensors - and the cost - is a very timely example of why I'm changing my opinion on extended warranty for the bumper2bumper. We keep cars for the long term, and the dealer is including lifetime coverage on power-train. That is a nice plus, but in light of the amount of computer/electronic components & systems in the current generation of cars, the likelihood of a simple but pricey failure occurring in that ecosystem appears to be a risk that changes the calculation for extending that coverage. The dealer will be presenting us with some options and quotes when we pick up the new Silver Sig this week; I am strongly considering adding that coverage.

Thanks!
I'm happy that I solved it. Since it started as an intermittent problem, I was worried about troubleshooting correctly.
As far as extended warranties go, I'm not big on them. The reason being that probability says that you will do financially better without them. These companies are in business to make money. not dish it out. However, each persons comfort level and needs are different, so for some people it is a smart choice because it's a form of security, and makes it easier to budget expenses. I like to do a lot of my own work as well, I view it as therapy, lol.
If you decide to go with a warranty, just make sure that everything is covered. I've seen too many garbage warranties that only covers stuff that never breaks. Some can be VERY limited. Read the fine print, consider the deductible if it has one, and make sure that you are buying what you think you are buying. I almost bought one many years ago for my wife's mini van (it was a Dodge, and always had problems), I even paid for it. However, after reading the fine print, I realized it was basically useless. Thankfully I was able to get my money back on it!
 
And I have the exact same issue... for me it isn't intermittent though, it just started all of a sudden (and it's possible that I was involved in a minor hit and run at the parking lot as i see a tiny scratch/push on my bumper, but i dont understand how such a tiny push could make the sensor go bad considering the sensor is attached not to the bumper but to the chassis)

Dealer got a code U3000:54 which is consistent with the TSB https://mazda.oemdtc.com/108/bsm-off-indicator-light-flashing-dtc-u3000-2013-2015-mazda and they quoted $2300 for 2 sensor and installation.

I am thinking that I will get the parts myself from internet discount mazda parts dealers (e.g. realmazdaparts) for $1100 or so and then take it to dealer and pay them $350 to install it. But I am worried, if the the dealer fails to get the BSM error off (due to any other issue such as they not calibrating it properly or something), they will blame it on the parts (as they didn't supply the part) and it would be a complex scenario then.

Any, long story ends with a short question, how complex was it to install the part after the bumper is taken off? What are the steps involved, can a monkey with a wrench do it? If yes, I am thinking that I will open the bumper myself (or ask a local shop to do it) and fix the part myself.. that way I will know exactly what's going on.

Unfortunately this issue is not very common and there is no youtube video or photo or anything how to do this yourself. Appreciate your inputs!
 
how complex was it to install the part after the bumper is taken off? What are the steps involved, can a monkey with a wrench do it? If yes, I am thinking that I will open the bumper myself (or ask a local shop to do it) and fix the part myself.. that way I will know exactly what's going on.
Roll under the right or left rear of the car and look up; you will see the module. I haven't tried yet, but it looks like you could remove it without taking the bumper off. It is tight, but I was able to see and feel all the mounting nuts (and I have large hands).

I have a flashing right BSM (just bought the car) and I have no need for BSM and it's crazy parts price. My plan is to unplug the module, which from what I've been told, will make all the flashing BSM lights go off.
 
The bumper comes off VERY easily, and worth it, just so you can work comfortably, trust me. After doing it once, that bumper can come off in less than 8 minutes. The modules just have a few screws on the base, and one jack, it doesn't really get easier than this as far as repairs go. After I replaced both modules, everything worked perfectly (In my case).
Good luck, let us know how it works out for you.
 
So I hadnt realized that there was a hit and run at the parking lot, and the bumper cover had a light mark. So I decided to go with the insurance.

The shop replaced the bumper cover (wasnt necessary I think, but Mazda says they have to when BSM issue resulting from a damage, probably BS). And then they replaced ONLY ONE sensor, and recalibrated and its working fine. I have warranty if it goes bad again somehow but I think it will not. Apparently the bracket that holds the sensor was also damaged.

So, I am glad that I didnt self order / install the 2 sensors as recommended by the TSB or the first dealer, cause I think my case was different and may be it would have needed fixing of some physical stuff on top of the sensor , which would have costed me more money then.

Geico took 2 weeks to get this resolved as they had to first fix the bumper, try with old sensor to see it works, before ordering a new one. But I had rental car coverage so it wasnt a problem really.

All in all, yes my car now has an accident record in carfax probably, but it was a peaceful process to get this fixed, and most importantly, realizing that contrary to what the Mazda TSB and also my first Mazda dealer said, they were able to replace a SINGLE sensor and get the whole thing fixed.
 
Make sure you add an adhesive sealant around the radar module. These things tend to fail very often especially in areas with a lot of rain or snow. They are all manufactured by AutoLiv (OEM supplier) and they all suffer this same issue. I've replaced 2 radar sensors in my mercedes and the cx9 has the same design.
 
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