BSM fuse

http://www.ttguide.net/blind_spot_monitor_system-386.html

full BSMS system breakdown with tech procedures for troubleshooting and locations of all bsms components

 

Looks like I now have the same issue that Rob has. I checked both the fuses mentioned above and they are good.

Mine just quit on the Hwy. stating that I should check the BSM system. Would a code reader help??? My neighbour has one..

Thanx.... John

 

Update:.... No codes in the system..??

 

I have a dead module in the left rear. And for the price of the module it's going to stay that way.

 

OK, my fuses are good..... Looks like a friggin' sensor (likely left one from what I've read)...

For the price , I guess it stays that way....!! I kinda liked the system, but not that much...!

 

By thw way how do you know the left sensor is dead,,?

 

After 3 visits to the dealer they finally figured it out.

 

Some of you are saying the left or the right side is gone. How do you know that?
My switch doesn’t do anything anymore. Never got a message about it. Just started flickering like crazy then shit off and won’t go back on. Any ideas?

 

I took it to the dealer to diagnose.

 

My only question is, if it was misdiagnosed the first time and you needlessly replaced a switch, how do you know that it is not misdiagnosed this time and that if your replaced your left rear sensor it still wouldn’t work? It would be nice to confirm it, but I understand that $850 is a high cost of verification. Still, I wouldn’t trust the dealer’s latest diagnosis given it’s first one.

 

This same thing happened to me maybe two years ago. Ended up being a faulty wiring harness. I was probably 6k outside the factory warranty. On top of that, my heated seats went too. I complained quite a bit to Toyota corporate and they split the bill with me. Still had to shell out 650. I havent used the BSM since but here in new england I use the heated seat daily.

 

Mine was the harness also. the rear harness that goes to that sensor.

I now have a loose connection in that area that lets water in now and then. The system works when it wants to (about 75% of the time)..

I put up with it now......

 

Don't run it HI as the wiring isn't big enough for a HI setting for long,.

Guys are having the amp. under the seat burn out...

My solution is only use setting low and med.

 

Good stuff. Makes sense, those seats get hot FAST!

 

The troubleshooting procedure is to pin out the rear harness connector for voltage and ground. If no BSM light on switch and no error messages AND there is voltage on the pin to the sensor and the ground is good then the sensor is assumed to be bad.

See above and this...
From what I understand, the left sensor takes the role of the master and the right as the slave, for lack of a better term. Both can be checked for voltage to them, but if the left doesn't work then the right wont work even if there is nothing wrong with it. I would guess there is a way to determine this but I am not sure if it is as easy as just jumping power to the right side sensor first, then over to the left.

There was a TSB for a rear harness allowing water intrusion that caused issues with the lic plate lights and could also affect the BSM module power wires. I don't remember what years it affected but there are troubleshooting procedures in is that will tell you if the BSM module(s) are getting power. It's just a simple voltage check at the connector joint on the harness.

 

Mine was replaced for a bad harness, when new. They fixed it with a new harness.......worked till off warranty.

Now it comes on and off in relation to the temp. and wetness. It works when IT wants to.

I never said it's the sensor......it was left wire harness going to it. & yes it is boss to the right one. Left not work---right no go.

It's a bit of trouble to get to the issue, but I think I'll tear it apart in the spring. Bumper parts have to be removed...I will have to clean and...seal the harness connectors and I think mine is fixed.

All my trailer wires function well.

Good luck

John

 

I've spent a year playing with the stupid BSM stuff and found a root cause issue. Wanted to post so no one wastes their time like me.

This is for a specific scenario where you have:
1) removed the bumper and disconnected wiring, battery off, etc. In my case it was a collision service (tree fell on my truck in storm, no lie)
2) lifted truck height with custom tire size, lift kit, new shocks, etc. In my case it was lifting a 2017 TRD Off Road 2.75" alongside new Bilstein shocks, upper control arms, and BF Goodrich KO2 tires

After I lifted the truck, I drove around and BSM worked. At least it appeared to work as the console light switch was on and the mirrors blinked when near other vehicles.

A few weeks later a tree fell on my truck in the driveway (cool story bro). Anyways, my truck sat at a collision center for approx. 3 to 5 days, with bumper off and battery disconnected while they ordered replacement parts. When I received my truck back it didn't work. The console light switch turned on, but nothing happened on the mirrors.

After digging into it with multiple visits to collision center and dealership, everyone continued to claim they didn't know what was happening. An error code showed TDTC U0232, U0233, C1AC1, C1AC2,
C1AB6, or C1AB7 https://static.nhtsa.gov/odi/tsbs/2019/MC-10162247-9999.pdf. I even submitted to Toyota.com corporate support.

Collision Center: We didn't do anything just put it back together.
Toyota Corporate: Go to your dealership.
Dealership: Mechanic said it's no longer active so Collision Center must have done something.

Time passes in which I read tips from Tacomaworld, Youtube, even tested the wiring myself, took the bsm devices off the bumper to inspect. All seemed unexplained. Over time, the console light switch stopped working. It seemed at this point the whole functionality was just disabled. I figured I would ask the dealer to recalibrate but the power was not on so not sure.

Finally, I brought back to dealership and spoke to an expert on the matter. I said I don't care about money here, I just want to know the 100% root cause. They looked at it again and gave me a logical explanation which I accept. The BSM has the potential to not work after changing the bumper height. It may appear to work for some time but it is not calibrated correctly. Overtime, through an event like resetting battery, disconnecting bsm devices, or just unrelated computer update, the BSM will stop working entirely. It does this as a safety mechanism. The console button light will not light up if the sensors recognize they are not calibrated correctly and have moved out of the stock position/height.

I honestly expected this to potentially happen after the lift, but the fact that it worked, then slowly deteriorated to death and no one could explain from a mechanic perspective drove me nuts.

Moving on, not going to fix it, just making sure I share the lessons learned.

 

Well this makes a 100% sense. Mine stopped working about 6 months after my lift was done. It was only 2.5 inch leaves but maybe this is the issue.

 

I ended up caving in and buying the Spottermirror.com blind spot side mirror modifications. I have a soft top on the tailgate and it just gives me peace of mind while night driving in bad weather conditions. But always look twice!