I will put my information in. I was involved in a major collision (three sides of the Leaf was hit), where I was struck from the driver side door, which propelled my Leaf into a light pole. The car that hit me did a 180 and smacked the rear of the Leaf. I kept the damaged Leaf for analysis in case of a lawsuit (against me or me suing the other party). What I discovered:
- Most dealerships (perhaps the service writers) do not understand or have sufficient knowledge of the "black box" and how to access it. Nissan support was of no help.
- I had to hire a accident reconstruction engineering firm to actually pull data from the black box.
- The Bosch CDR tool was used to pull the data. This can be done via the OBDII port or directly from the box itself. https://www.boschdiagnostics.com/cdr/
- The black box is actually the airbag controller that sits under the center console (or storage cubby). The unit itself is a Bosch unit. Prior to junking the Leaf, I removed the airbag controller unit and kept it safe just in case.
- The airbag controller unit stores: DTCs (any error codes at the time of data retrieval), how many times the car has been turned on AFTER the crash (presumably for vehicle tampering), whether or not the driver or passenger seatbelt were buckled at the time of collision, it also contains an accelerometers to determine crash impact forces, etc.
- The Leaf stores about 5 seconds of pre-crash data. It can sample data at 2 times per second. The data it that it tracks are, speed (as sensed by the car's speedometer), accelerator pedal position (how much % full you were pressing it), engine RPM (but that's not relevant here), motor RPM, brake pedal being pressed or not (it senses via the brake pedal switch), and the steering input (how many degrees have you turned the steering wheel left or right).
- The data from the Bosch CDR gets put into a very detailed report. Not exactly easy to understand without some level of interpretation. For instance, I had the accident reconstruction engineer take the data and compile it with my dashcam footage and we determined that I was struck at approximately 32mph into my driver side in my accident. Not something I could easily figure out with the data and without the math and engineering background. This was information was critical, because the police report from my accident says the other vehicle slowed down prior to entering the intersection and hitting me, while witnesses say otherwise.
- To pull the data and reconstruct the accident can easily cost into the thousands of dollars. All I had the engineering firm to do was just to pull and run the basic math to see the speed I was hit at was already nearly $1000. I can see why many insurance companies won't want to do the crash data retrieval, unless the accident was trivial or there was major injury or death that resulted. Likewise, pulling the data in a accident can help you refute claims against you. If it was a serious accident, find a accident reconstruction engineering firm to pull the data immediately. If you cannot, find someone to help you remove the airbag controller and preserve it (do not drop the unit). It lives under the center console storage area. I was able to remove it myself in under 15 minutes. Beware of sharp edges on the mounting plate the unit is attached to.
Thats what I know.