You are describing one scenario where this invention could be used ("a system that calls 911 when it detects a crash").
The legal protection provided by this patent is _not_ limited to any specific context or scenario.
Let's take '707 claim 6. _Any_ commercial product with each and every one of the following bullet points ("limitations" in lawyer-speak) infringes and must purchase a license to this patent.
[1] A vehicle, comprising:
[2] a factory-installed first apparatus configured to generate an electrical signal;
[3] a factory-installed second apparatus configured to receive the electrical signal; and
[4] a retrofit apparatus electrically connected to the factory-installed second apparatus,
[5] wherein the retrofit apparatus generates a mimicked electrical signal independently of the electrical signal generated by the factory-installed first apparatus, and
[6] wherein the factory-installed second apparatus receives the mimicked electrical signal.
A lead would need to teach significantly more to even be considered.
Does the vehicle have (1) an after-market device installed that (2) detects that a first component stopped sending commands to a second component and (3) uses relay switch to disconnect the failed first component from the second component and (4) starts sending commands to the second component on its own that are indistinguishable from those sent by the first component?
Technically, the above requirements are needed against claim 20 of '707. Claim 6 requires fewer features.
That doesn't help us because:
(1) claim 20 is asserted in the complaint [0], and
(2) claim 20 was upheld in a previous challenge to its validity (an "IPR"), so it's got some staying power.
The above link is a published application rather than a granted patent. US20170170984A1 by itself carries no legal rights whatsoever.
In this case it was granted with largely similar claims (as US10027505B2). However, claims typically get significantly revised by the time they are granted, and less than half of applications are granted at all.