2005 Prius - codes P3000-123 and P0A84

Since you all helped me so well with my 2008 Prius issue a couple weeks ago, my 2005 Prius decided it wanted some attention too.

2005, over 240k miles, no major issues before. A few days ago, the red triangle came on as I was at a stoplight, plus the exclamation mark icon on the MFD. Didn't notice anything unusual as I drove it the last 2 miles home, but I left it alone in the garage for a few days while I acquired a Techstream device. Finally got a reading today and it's giving me two codes: P3000 with INF subcode 123, and P0A84.

Scouring the forum tells me this:

P3000 - HV Battery Malfunction
123
Input of abnormal signal from battery ECU (HV Battery System Malfunction)

P0A84: Hybrid Battery Pack Cooling Fan 1 Control Circuit Low

The only recent issue I had with the car was the 12V battery died about a month ago, not unexpectedly. I replaced it, changed the oil, changed engine and cabin air filters, and drove it for a couple hundred miles with no issue -- until the red triangle and these codes popped up the other day.

I did also over-fill the gas a bit recently -- darn pump didn't shut off as expected! Nothing spilled out, and it didn't trigger a check engine light or anything, but after that generous fill, I took a day trip of 135 miles and the gas gauge on the dash still said full when I got home. MFD reported ~47 MPG in that time. My next drive was a few days later, a short shopping trip where the red triangle light came on. The gas gauge still says full. Again, it doesn't seem like this would be related to either of those codes, but I figured I should mention it.

What should be the next step of my testing or experimentation? Or is this beyond the scope of an aspiring DIYer?

 

Thanks for the tip! Sure enough, during my recent day trip, I drove through some heavy rains (and parked in the rain for awhile too).

I opened up the back by the battery fan, and there's definitely corrosion on the white plug:

Prius-fan-plug by spycake posted Jul 1, 2020 at 9:30 AM

Any tips on cleaning? According to this other thread, I should pick up some "electrical contact cleaner" and also perhaps something to seal the leak:

DASH Error Lights Exclamation w/Triangle, VSC, and small Exclamation - Car runs great? | Page 3 | PriusChat

 

Update: Whoops! I pulled that white plug, and unfortunately the corroded connector snapped right off. You can see it missing in the lower right of the first picture below -- it's now stuck in the opposite plug, upper right of the second picture.

Am I going to have to do some advanced wiring repair? Otherwise, I'm about 1.2 miles from the nearest auto shop...

Prius-fan-plug-1 by spycake posted Jul 1, 2020 at 11:31 AM

Prius-fan-plug-2 by spycake posted Jul 1, 2020 at 11:31 AM

 

Thanks, that sounds like a good plan. Any leads on where to find a part number?

 

Thanks for the advice everyone.

One last question: after I repair/replace the corroded wire, is it best to leave the codes and warning lights and wait for the system to clear them, or should I clear the codes and hope they don't come back? Not sure what the "best practice" is.

 

Update: someone gave me a few "bullet connectors" (male/female), so I disconnected the 12V battery, pulled the broken/corroded wire from each side of the battery fan's large white plug, stripped the wire a bit, and stuck it into the bullet connector. I left the other 3 wires in the white plug for now.

Drove around the neighborhood a bit and no warning lights have come back. I'll keep an eye on it going forward.

Thanks again for all the help!