2010 Toyota Prius fuse problem

My Check PCS Light came on for my 2010 Toyota Prius. I read somewhere that it could be the battery not providing enough voltage. I check with Multimeter and found a parasitic drain of about -2.0amps. When i pulled the ECU-B fuse, that went to nearly 0. Now I am stuck figuring out what that means or how to fix it. The car wont run without this fuse (not like I can just disable the radio and ignore). So how do I stop this drain? What is actually wrong? Isnt the ECU the main computer of the car?

You may have to monitor the draw for up to 30 minutes with the doors, trunk and hood closed to reach a normal value, there is likely nothing wrong as far as a battery draw. If the battery is weak/failing replace it before further testing.

PCS is Pre-Collision System, a professional diagnostic scan tool will be needed to read the faults in that system. Is there any damage to the front of the car near the radar sensor?

I would agree: definitely eliminate the battery first as the cause of a warning light. When my wife’s 2006 battery failed a while ago, the transmission failure warning light came on. Once the battery was replaced, there were no more problems.

How old is the battery?

Battery was only 5 months old. I just had it replaced yesterday with Optima Yellow top. Same issue. I’ll put a multimeter on it and see if it is good, but highly unlikely that 2 batteries in a row are bad. Gotta be the car at this point. And I think I hear some sort of Arcing or Sparking coming from the back when I drive. maybe there is a wire with a crack causing some arcing and loss of power?

When it comes to electrical issues like this, I find an expert.

You might try posting this on a Prius forum, maybe somebody there has had the exact same problem (Priuschat, for example).

Agreed. Thanks for your advice. I’ll probably just take it to a mechanic/dealer at this point.