[Steverino]

I'm guessing a percentage indicator is using a calculation based on miles driven. I know that sensors work by wearing down with the pad until a wire is exposed setting off a dash light. But a percentage indicator seems like it's a guestimate. Otherwise, it would need to be continually measuring pad thickness.

 

[Steverino]

I don't think it's going to just be miles driven, the car knows the speed, regen, and when the physical brakes are used too... so it's a little more accurate than that.

You'd hope, but so far I'm not finding any details. I also looked in the 2022 Hummer EV Owners Manual.

 

[Steverino]

Measuring piston travel or fluid displacement in the brake line doesn't seem THAT tricky. Just finicky due to small amounts/measurements between 95% and 5%.

Why not lasers?

I'm thinking this may be a future tech advance for 12 or more months from now, or simply a mistake. I'm not seeing this feature in the 2023 Cadillac Lyric owners manual.

Given that an idiot light is apparently state of the art, it makes me wonder why the graphic is showing a % of life stat. Maybe part of an OnStar service rather than a car feature?

 

[Steverino]

But that doesn't need to be onboard, nor are 98% of owners going to even want it.

Heck, from what I see, 98% don't read the Owners Manual, even when the answer to the question they have is in there!

I do think having the actual error codes display in a submenu would be nice for those who care to then look them up to get an general idea of what the issue might be.

Here are the Volt DTC's (Diagnostic Trouble Codes, aka Fault Code or error code) to give an idea of what these look like:
11OBDG01 HYBRID Diagnostics Part 1.pdf
11OBDG01 HYBRID Diagnostics Part 2.pdf