BSD (Blind Spot Detection) 2019 RETROFIT NOT WORKING

Discussion in 'Subaru Impreza' started by CharlieMSU, Jul 7, 2020.

  1. CharlieMSU

    CharlieMSU

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    Hello all, this is my 1st post here, apologies in advance if the topic has been covered elsewhere.

    IN SUMMARY, I retrofitted my 2019 Impreza Limited with the Blind Spot Detection (BSD) module, sensors and wiring. The BSD button on the dashboard is RED even with the engine off. Pushing the button won’t change the color on the button nor enable the BSD function. I got no error codes or beeps. Everything else in the car is operational. Here’s where I need your help:
    1) Would you happen to know or offer any troubleshooting help on the BSD circuit, although interconnected per the original wiring diagrams, will not turn BSD on/off?
    2) If the answer to above is “ECU has the BSD feature disabled by factory, therefore you need to re-flash the ECU program”. Is there any way to get it done? Dealership or no dealership? How would I even approach someone to do it? I ask assuming VIN numbers need to match the accessory modules / features / ECU program installed in each vehicle at the factory.
    3) Or, if I’m lucky, could the BSD feature be enabled in the ECU per simple connection to laptop with OBD software?

    *** If you do NOT care to know how the physical retrofit took place. Save your time, stop here, there’s no need to continue reading. :)
    *** If you are curious, proceed at your own risk. (Spoiler: it’s a long story!)

    So, I’m done, or so I thought, with the hardware part of retrofitting my son’s new 2019 Impreza Limited Sedan with BSD (Blind Spot Detection). Here’s what it entailed:
    - New mirror shells with additional wiring. (Both sides)
    - New BSD sensors under the rear bumper. (Both sides of the bumper)
    - New wire harnesses to the entire left and right sides. Both harnesses going from the doors all the way to the rear bumper.
    - New BSD module under driver’s seat
    - New BSD switch replacing the blind cover on the dashboard.
    - Took the opportunity, since I had all carpeting, seats, etc, out of place, to install a new amplifier module (from the sport trim) under the passenger’s seat, and the upgraded speakers that comes with the kit. (One speaker on each door)

    I have a limited trim that I ordered to be fully loaded but got delivered loaded but missing BSD and upgraded sound system. That explains why I took it upon myself to add it after the fact.

    I had to look up the VIN of a Sport trim vehicle in order to locate all the new parts I needed, especially the harnesses. I was naive to think the harnesses would be the same for all trims (Just In Time - JIT manufacturing these days) but it turns out the harnesses are CUSTOM by VIN. (I mean, for the different packages each VIN comes with). In other words,
    1) the harnesses are not the same for all trims, where the manufacturer only changes what modules to plug in based on trim.
    2) the harnesses are not different per trim either! I mean, there isn’t a harness part number for Limited, one for Sport, etc. That would make installers lives so much easier! But manufacturers don’t want that!
    So, instead, each VIN indicates the features that particular car has, and therefore the part number of the harness that goes with it.
    Here’s what happened to me: Remember I told you I got a VIN of a, apparently loaded, sport trim Impreza with BSD. So I ordered the harnesses with that VIN, a week later they arrive (both left and right sides), guess what? The right side connects to everything, including the BSD sensor, and it comes with the connector to the audio amplifier as bonus. The left side harness though, it connects to the BSD sensor and module I needed it for (yay!) but it’s missing the whip and connector to the Rear Automated Braking (RAB) module that my car also has! WTF! There we go again, I had to search dealerships all over the US for a 2019 Impreza that contained both BSD and RAB and everything else my car came with, including the driving assist feature, lane departure, etc. I got lucky, found the vehicle, got the VIN, ordered the left harness to that VIN and a week later: bam! We’re back in business.

    After a lot of frustration with the harnesses, and with how Subaru installs the carpet and how tight it is to run the harnesses under and through the holes on the carpet, all that while the carpet is either glued or clipped to the floor; and how it also required me to unglue the roof cover just to run the branches off of the new harnesses, I GOT ALL THE HARDWARE IN PLACE! And one, including the dealership master tech, cannot tell it was retrofitted. SCORE!

    Now comes an issue I was NOT expecting: start the car, all modules check and pass, including the new audio amplifier and BSD. The sound is sooo much better!
    However, the BSD switch won’t turn the BSD feature ON. Actually, with car started the switch is all dark. With car shut down, the switch is REDish, as in feature is ON. I checked the fuse, the fuse is there (had been there already, even though the car didn’t come with BSD), test the fuse it’s good. Then, after driving it for a while so the tire pressure monitoring system (TPMS) could reinitialize and display the PSI in the tires, I noticed the BSD switch is not red anymore, not even with the engine off like it showed redish before.

    BOTTOMLINE, the BSD hardware is installed, I get no error codes from the ECU, but the BSD feature won’t turn on. MY BIGGEST FEAR: the need to re-flash the ECU but not to my VIN (it didn’t come with BSD) but to a VIN that has all that my car has, plus BSD. For sure, it will be impossible to get that done, for obvious reasons. I’m positive no dealership will offer help either.

    Here’s where I need your help:
    1) Would you happen to know or offer any troubleshooting help on the BSD circuit, although interconnected per the original wiring diagrams, will not turn BSD on/off?
    2) If the answer to above is “ECU has the BSD feature disabled by factory, therefore you need to re-flash the ECU program”. Is there any way to get it done? Dealership or no dealership? How would I even approach someone to do it? I ask assuming VIN numbers need to match the accessory modules / features / ECU program installed in each vehicle at the factory.
    3) Or, if I’m lucky, could the BSD feature be enabled in the ECU per simple connection to laptop with OBD software?

    My sincere apologies on the long text, I just want to make sure whoever offers help will get the full story. Plus, hopefully it will save someone else from making the same mistakes I made when doing a similar retrofit.

    -Charlie
    2019 Impreza Sedan Limited
     
    CharlieMSU, Jul 7, 2020
    #1
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