Cars: Technology That Is Too Complex-Part 2

...part 2 of 2

However, before we could replace the boot, during this 15 mile drive to test it, I rolled my passenger window down to listen for if the engine was misfiring. I was so glad that I heard no misfires, but as I rolled my window up...well, that's the thing. My window didn't roll back up. -_- After much more Googling, we found out that it was most likely the window regulator. After driving to two different auto stores to find the BMW passenger regulator, we spent 2 hours taking the door apart, unplugging the window motor, the speakers, and the airbag. More on that in a second. We plug back in everything as it was, and after much grease and stress of breaking the window in the process, the door is reinstalled, and the window works perfectly! However....on the dash, the airbag light came on. After more Googling, and calling to auto stores, we learned that, because we unplugged the airbag WHILE the car had its battery connected, the possible failed airbag light came on, and the only ones who can turn it off is the dealership for $60 for 2 minutes of labor (which they bill as 30 minutes). So we had to pay for them to click a reset button. Amazing.
We then proceeded to replace the brakes, as they squeaked quite loudly when braking. However, squeaking should have been the least of our problems. The car still gave us 20 error codes through the OBDII port that connects to the computer. 6 of them said the engine was misfiring, and another 14 said that the transmission was pretty much failing. After some Googling, we cleared 6 of the codes by swapping the camshaft position sensor, which helps regulate when fuel injectors fire fuel into the engine. That still left 14 more codes for transmission...which, as we narrowed it down, could be a few things:
1) Failed/shorted wiring harness
2) Failed TCM (Transmission Control Module, is the computer behind the transmission)
3) Bad transmission coils (help change gears by letting in or closing off the transmission fluid)
4) Needs new replacement transmission fluid

Unfortunately, all of these things require money to replace, and can only be tested by replacing them. However, while we will figure this out in the coming weeks, there is an important lesson to be learned from this: Cars are similar to computers, with many sensors and computers. However, they are difficult to diagnose even with these systems that seem to complicate repairs.

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