what else can I check? possible ABS actuator issue?

When u press on the brakes all the way, do you get the brake bark that seems to come with most of the actuator problems?

 

I usually only get a short duration of brake bark only when the brake pedal is pressed hard all the way in, I would try to get the techstream codes if any, and then compare them with the manual code description as you dont seem to have any loss of braking power when the lights are on, which could be less serious issue. I would also check your cars engine oil if it is low or not, on a level surface. Hopefully more experienced users can chime in as well.

 

You definitely want to get a mini VCI and Techstream setup to diagnose this properly, I'm sure there are ABS codes stored in there you can't see yet without it.

 

And it keeps repeating at this approx. interval? If so, the actuator is leaking (a lot).

 

my 2008 prius has 163k miles, and for my car the actuator during idle does not turn on and off every 5 seconds thats for sure, def longer pauses before it cycles on. But honestly im not even sure what normal actuator cycle is when the car is on idle.

 

The actuator (electronic) should be closed unless the vehicle is activating the ABS function or traction control. When unpowered the normal state for the valves in the solenoid block is for them to be closed (when actuated the solenoids are open). It's normal to hear the ABS motor buzz if the sensor sees low pressure but if the solenoids are leaking then you can start to hear the motor buzz more often and it may cause some other weird symptoms like some are seeing above.

 

'Normal' in my experience is to hear the pump usually when opening the driver's door after sitting overnight, and to hear it while driving every every, um, handful of uses of the brakes. 'Handful' is somewhat variable, depending on how hard you were braking and the condition of the brakes themselves. Still, 'after every handful of uses' does not encompass having to continually pump itself back up while just sitting there. That one has rung down the curtain and joined the choir invisible.

 

I see, yes normally i dont hear the abs noise until i open the car door to start it, however, most of the time when driving, after i have the foot on the brake pedal at a stop light after i let go, most of the time the actuator noise will go off to re calibrate. Im assuming it could a slightly failing pump, or there is some air in the brake lines.

 

Nothing about re-calibrating, all it's doing is pumping pressure back up, just like a well pump if you have well water.

There are a lot of Prius things that it's possible to obsess over, with scant evidence that obsessing is helpful. If you are occasionally, or most of the time of most of the time for two unspecified values of 'most', hearing the pump when you have used the brakes, maybe it's possible there's some incipient problem or maybe it's possible you're thinking yourself into one.

If a problem worth fussing over develops, it'll be more obvious.

 

The ABS system should build up pressure in the accumulator when the car first starts up. If all is working correctly the pressure it builds in the accumulator (pressure tank) is similar to what you could develop when stomping on the brake pedal very hard. The system effectively allows you control unless you activate the ABS or VSC.

This is very technical but it has some helpful diagrams on how the Prius braking system works:
https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1017&context=auto_pres

If the pump is running every time you step on the brake it is possible one or more of the solenoids are slightly leaking pressure back into the braking lines or the MC. If it is fairly infrequent then you are probably fine for now. If you start hearing the ABS kick in far too often even when stopped at idle then you should definitely consider replacing the ABS assembly.

This is what it sounds like when the solenoids are leaking on a Highlander:

Notice how often it runs without even using the brakes at all. In this case the aluminum solenoid block behind the pump and accumulator needs to be replaced to fix the issue. On a Prius unfortunately they are one piece so typically the entire ABS assembly must be changed.

 

That changes between different Prius generations. This is the Gen 2 forum and it is true for Gen 2, but shouldn't be gen-eralized to other years.

 

It could also be a shortcoming of the cheap MVCI cables. Quality control is not the greatest (to non-existent) and we have a lot of reports of things not working right or missing features is Techstream.

 

It was implied since this is a gen 2 section of the forum but always helps to clarify for others.

Is it really a function of the cables or is it the version of Techstream software you use? The cable doesn't make much sense since it should just set the protocol for communication between the laptop and the on-board computers. I would try another version to see if maybe the cable manufacturer was possibly providing (via CD or link) some neutered version of Techstream for some reason.

Looks like this also confirms it's likely a software problem.
Toyota Techstream Not Able to Customize Settings Solution | OBDII365.com Official Blog

Try this and see if it works better.