Gone are the days when you could toss your CDR kit in the truck, head to an inspection, and be nearly certain you’d pull all pertinent data with ease… like The Fonz smacking the jukebox.

Nowadays, I find myself combing through the CDR help file, Monroney labels, RPO codes, CDR group messages, and phoning friends prior to an inspection.

Take a 2024 Chevrolet Silverado for instance (a model I’m heading to interrogate today). The help file indicates the vehicle will be equipped with an ACM (airbag control module) or ASCM (active safety control module), an OCS (occupant classification sensor), and might have a FCM (front camera module).

As you’ll find when discussing this vintage FCM with colleagues, sometimes the download goes as expected, and sometimes it doesn’t. There are still some bugs. As such, prepare by learning from war stories and keep your fingers crossed.

Regarding the OCS, I’m aware of the device but didn’t know you could acquire data from it! I reached out to a few colleagues to learn more and was relieved that Kent Boots could assist. In fact, he recently created this post about it, and was kind enough to share the related images.

 

View of a GM OCS sensor under the driver's seat. The sensor measures the pressure in a fluid-filled bladder mounted under the seat cushion, and informs systems accordingly.

 

Bottom line, CDR-compatible OCSs from GM go back to 2020, but Bosch added a lot of support for them in December of 2024. The sensor can be interrogated via the DLC and CDR900 using CDR2 and, for deployment events, should capture vehicle speed for 30 seconds prior to the event. 30 seconds!

While CDR interrogations are becoming more complex and unpredictable, we’re getting access to more data that help us reconstruct a collision with more detail. It’s not easy keeping up, but that’s the task!

Thanks for reading, keep learning.

Lou Peck
Lightpoint | JS Forensics

P.S. The 2025 Joint Conference, hosted by NYSTARS will focus on ADAS, if you're in need of some solid training. Alan Moore, Steve Anderson, David Sersen, and Nick Manz will be presenting!

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