Fuzzy Logic

We had a 2007 BMW 328 series car come in for a problem with the right rear window being stuck in the down position after a loud snapping noise occurred while lowering the window.  We disassembled the door and found the window motor itself was good but the regulator had failed.  The part was ordered from BMW, installed fine, and upon reassembly, the retest of the window showed everything working well.

The next morning, we came in to work and as we began to unpack the shop for the day, we noticed all four windows were down in the BMW.  They had all been left in the up position when we’d left the night before, so the car had put the windows down on its own.  Yes, this is possible.

In trying to put the windows back up, we noted a problem with window functionality that had to do with the computer controls on the car.  Since we don’t have a BMW-specific scan tool, we took the car to a BMW specialist to have him look at it.  He scanned the computer modules and noted numerous codes in the various computers, then attempted a “renormalize” procedure to essentially retrain the computer and the new window regulator.  The process did not work, so we made arrangements with him to bring the car back when there was more time to delve further into the system.

While driving back from his facility to our shop, the technician attempted one more time to operate the windows, and suddenly everything was working fine.  All four windows began to operate up and down in normal fashion, with no explanation as to why they suddenly worked.

If you ask the engineers and designers of these automobiles, they’ll tell you that this sort of thing cannot happen.  Yet we see it day in and day out.  The computer systems are so advanced, so complex, and there are so many of them on these new vehicles, that trying to untangle the data lines and diagnose electronic issues is a very advanced science.  It takes training and expertise to be able to work with these systems (not to mention specialized tools), and sometimes even with all that there are difficulties and problems that are not easy to find, let alone fix.

Computer system are only going to become more entangled, and cars are going to become much more difficult to diagnose and repair.  That is why our technicians are constantly attending classes on new technology and renewing their licenses to make sure they are up-to-date on the latest automotive systems.  The industry is no longer a matter of a simple turn of a carburetor screw to fix a running condition.  These days, technicians must be very thoroughly trained in order to understand these complex systems.  Even then, we sometimes get stumped when something happens that cannot be explained, like a BMW that won’t take a retraining procedure, then suddenly renormalizes on its own.