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I have a C7 that was involved in a crash and I have extracted the Airbag Control Module (ACM) data. The Bosch downloader provided accelerator position, throttle position, brake on/off, RPM, and vehicle speed. I was looking online at the Aim Technologies website and it indicates that the C7 also has data storage channels for individual wheel speed and steering position. Has anyone out there pulled this data before? And would this be on the ACM or is it in a different module? Many thanks for your help.
They say they got 174 pages from a newer Silverado. You would think wheel speed and steering angle would be in a report that size. Maybe you need a different or newer version of the program?
Thanks for your comments. The company that pulled the data reported the Crash Data Retrieval tool was using the latest software version (21.2). Report was 50 pages covering 3 deployment events (2 were basically the same event separated by a fraction of a second). That included a full printout of the raw hexadecimal data for the 3 events. I am checking with the company to confirm that all ACM data was recovered... and checking with another company to make sure that all expected data storage has been included in the original report.
If anyone out there has been able to recover individual wheel speed and steering angle data from ACM storage it would be great to hear from you. Or alternatively if you have tried and can confirm it is not there.
I get pretty deep into the nerdy side of these cars, and you're the only person I've ever seen even mention this topic. Maybe someone else will be able to chime in, but I wouldn't get my hopes up.
The professional data recovery company I used has confirmed that GM does not store individual wheel speed and steering angle as part of the crash event data written to the ACM. It is my understanding that these data are reported to and processed by on-board control systems... but not saved as part of an airbag "deployment event".
On a different but related tack... has anyone out there evaluated reported accelerator pedal sensor position vs. the throttle sensor position? This data could come from real time ECM monitoring or ACM stored data. The ACM data below came from an event that started at over 95 mph (t minus 5 sec) but had slowed to under 40 mph at the time of impact. One interesting observation to me is that the accelerator pedal sensor reads zero (percent of full open) across the 5 sec period (corresponding with driver being on the brakes, as the brake circuit was reported "on") but the corresponding throttle sensor never went to zero. Does anyone know if this is normal for a late model corvette, or any other performance car for that matter? Does this signal that the car engine is still under power or is it just a function of higher RPMs pulling air through the throttle body while minimal fuel is being supplied by the fuel injectors? Comments appreciated.
I don't think it'll ever go to zero because that would risk stalling the engine. Older cable operated throttles had a separate idle air valve to make sure the engine could still breathe while the throttle was closed. Electronic throttles combine both functions. So it'll always be open a little bit for idle control.
C7 data available on ACM / ECM
