BSM not working 2014 Tundra Platinum

I have a new to me 2014 Tundra Platinum with 120k miles. The truck is in wonderful shape, but I noticed the other day that the BSM does not function. The light does not come on when the switch is pressed in and there are no lights in the mirrors or audible indication the system is working. It's worth mentioning the truck is stock, so no tow mirrors or aftermarket bumper. Per Carfax, no accident history.

I have an extended warranty I purchased with the truck and the dealership is looking into it. They first replaced the switch and it did not work. Now they are replacing "the module." My concern is two-fold. First, this is a GMC dealership so they're likely guessing. Second, when I looked up the components of this system, the only listed "modules" are the sensors themselves. I'm worried the dealer is just throwing parts at the problem.

I have only found one thread that followed through a non-functioning BSM until the end and it the problem for that thread was rodents chewing through the wires.

Anybody else ever gone through the BSM not working?

 

Nobody?

 

I have no idea what could be wrong, but I have to ask. Why a GMC dealer? Also if they parts aren't costing you anything then let them throw as many parts as they want. 99% sure that modules need to be married to the ECM/BCM. Wonder if they even have a Techstream to do this. Or to even diagnose the problem.

 

Attached are the wiring diagram (from this thread) and the Factory Repair/Service Manual sections for the BSM system.
I've not messed with the 2014 BSM, but I have installed the factory system in my 2021. The system is relatively basic - two rear radar units (master on the passenger side, slave on the driver side). LED in each mirror. A buzzer for RCTA only (which I didn't include in the FRSM pdf). An activation switch (on the 2018+, this is actually controlled in the instrument cluster), which controls power to the master radar unit. CANBUS wiring to control the details of the system, and then some integration into things like speed sensor, reverse sensor, etc. that set how the unit is activated if power is turned on. There is not a separate ECU for this system, and the only integration to the main ECU or any other ECU's in the truck is solely related to the CANBUS signals for speed, transmission shift position, and turn signal status.

Anyway, the attached PDF from the FRSM should give you a detailed set of steps to actually check out the issue using a multi-meter and following the troubleshooting steps.

 

GMC dealer because I bought the truck from them used and the warranty company wanted me to go there first. They advised me if they cannot figure it out, they can ship it to Toyota. I only worry about them throwing parts at it because in my experience, nobody quite puts the vehicle together as well as the manufacturer. The more they tear into it to figure it out, the more I worry about problems down the road.

Seems like it's not a common issue which is good and bad I suppose. At least common issues have common solutions

 

I get what you're saying. Mechanics always have spare bolts left over, lol. Well at least if they don't fix it, they will sent it to Toyota. Good luck

 

Hope you can get it resolved.
The last install I did, we had some issues (bad terminal in a wiring harness). Good old multi-meter continuity checks was the best (and least expensive) tool for trouble shooting. If they wires all check out end-to-end, then start looking at replacing components. But if a wire shows no continuity (or strange numbers), that’s the first thing to fix.

 

You might give the dealer those two PDF’s too. I’ve got a feeling they’re not using the official Toyota TIS system and manuals to do their “trouble shooting”

 

Sorry to thread jack...
@RainMan_PNW
So 2018+ do not require a switch for the BSM?

 

I know, holy thread resurrection. But I wanted to update in case anybody else has this same issue.

I narrowed the issue down to a faulty BSM module under the bumper. I replaced it and now the BSM switch works and lights up. However, I immediately received an error in the Dashboard advising to service the BSM system. After further research and a call to the dealer, this is because the module is new and requires calibration. This can only be performed at the Toyota dealer and is quite expensive. That's my next stop and the issue should be resolved.

 

I replaced my drivers front bumper sensor after some dipwad rubbed his (apparently red) car across my front bumper in a parking lot. Bought a well reviewed but cheap knockoff from Scamazon. Installed and plugged it in and it worked immediately with no calibration.

 

Interesting. I can only advise what I have been told by the dealer and it seems to be backed by some forum posts I've seen. I can say I went from BSM switch doing nothing to at least it now throwing an error, so I suppose if calibration doesn't fix it, I might have to go down another path. Thanks for the info!

 

To be fair, the BSM worked regardless of the bumper sensor, mine was all parking proximity sensor related.

 

In your original post, did you mean there are no lights in your mirrors?
I ask because I bought a used 2017 1794 in 2021. When I turned on BSM, the Service BSM Error popped up. Apparently, the previous owner replaced the mirrors with ones (not towing mirrors) that didn't have BSM indicators lights. I got replacement mirrors with BSM lights and now it works.
I guess Service BSM error comes up if the circuit to and from the lights is not complete.

 

No, I have the lights. Originally, the BSM worked occasionally when hitting a bump. Then not at all. Checked all wiring and was perfect. Did some tests with a multimeter based on a wiring schematic I found online and diagnosed the sensor. Replaced sensor and now it just beeps and gives warning. Mirrors are stock and have lights on them.