I think the rear left caliper on my wife's 06 HiHy is sticking. Its grinding the rotor down and doesn't release immediately after the pedal is released. It grinds for a while until we get up to speed. It is a fairly recent issue.

I'm learning about the regenerative braking system and it looks like if I have to replace the caliper itself I need a scan tool to run the bleeding procedure. Does that sound about right?

 

You shouldn't need a scan tool for bleeding unless you run the master cylinder dry of fluid......scan tool just lets you open the ABS for bleeding.

 

I was told that since the computer system actually controls the brakes (determining whether to use the regenerative or the hydraulic brake) pushing on the pedal by itself won't actually do anything and that attempting a traditional bleed will mess up the computer system causing it to think there is a leak due to loss of fluid on that corner.

Not true?

 

You are right that the vehicle does decide when the brakes get used versus when to use regen (depends on both the vehicle's speed and the current state of charge on the traction battery). I believe at low speed (under 5 mph) or at rest the brakes are working by default (safety issue). It would be easy to tell by having someone press on the pedal with the car on (in park) while you crack the bleeder on the brake caliper. If fluid shoots out then they are hydraulically connected and you can bleed them normally. In any case having a mini VCI setup (around $25 on amazon and you need a Windows based laptop) will allow you to bleed them electronically.