P3000 / P0A84 Code and Triangle Warning Light. Hybrid Cooling Fan loses power intermittently

If this is a 2007 we're talking about, the battery blower isn't controlled from the HV control ECU in the dash; it's controlled by the Battery ECU inside the battery.



To make the blower run, the battery ECU has to do two things: (1) it pulls FCTL1 down, so the battery blower relay will close and supply power, and (2) it outputs a pulse train on SI to the battery blower motor controller, which pulse-switches the low side of the blower so the widths of the pulses control how fast the fan runs.

The voltage on the low side of the blower is monitored by the battery ECU on its VM input to make sure things are going as planned. The higher the wanted blower speed, the lower VM should go. (For lower blower speeds, VM rises up closer to 12 volts, so there is a smaller voltage drop across the blower.)

 

There are related INFs (subcodes) for DTC P3000, you will need a capable OBD2 scanner or "techstream" to retrieve such.

 

In all your exploratory efforts, did you check the connector inside the right-rear fender above the actual battery fan for corrosion? If you have hairline cracks at the roof seam by the top of the rear hatch, you can get water dripping on the fan connector that eventually corrodes and causes unreliable power to the fan relay.

 

I'd look at that white connector at fan in rear and or check temp sensors on

 

At this point I would suggest using a (capable) scantool to command the fan ON then measure voltages at each of the 4 wires of the fan speed controller (while everything's plugged in and the car is ready).

If there was a problem with a temperature sensor, then it wouldn't set the codes you have. That said I would use a scantool to view temperature data in the HV battery ecu.

For this (limited) task, Dr Prius is adequate, but there's two other scantools that have "full" bidirectional controls. Here's a scantool review thread.
https://priuschat.com/index.php?posts/3290690

Posted via the PriusChat mobile app.

 

Well, it wasn't really "Toyota" recommending that ... "Toyota" published the service manual and wiring diagrams, which can be used, as I did above, to see how stuff actually works.

Sometimes the mechanics at their dealerships even show signs of having read them.

And sometimes not.

 

Well you are in Pennsylvania so no telling what's really going on like others have said command the fan with whatever programming tool you're using if it's capable If not get somebody with TIS2 to command the fan to run see if the fan runs and all the speeds and work backwards from there like has been mentioned. Jumping out the white connector in the back is a pretty standard operation so that's been handled I think I remember you talking about this before. So that's out of the loop. So other than the fan speed controller and what have you that's pretty much it and yes I would think it would be the ECU back in the battery not up in the front of the car as the fan temp sensors plugs and all that are back there near the battery hello how one would think a computer way up in the front of the car would be handling this just by sure thinking about it seems kind of silly when there's a battery ECU right in the battery case in the back of the car with the battery the fan and all the rest of it. Just seemingly how I would think about it anyway why would you run a harness 15 ft up to the front of the car to handle that when the battery ECU is already back there with the battery but anyway.

 

I never ever hear my fan in the deep south and central North Carolina until after June and I'm not sure when it stops or me not hearing it begins again probably in October or November seriously. I listen for and can hear it not generally while driving but when I pull into the driveway to get ready to turn the car off whether I'm at my house or at a job doesn't matter as I pull in I'll hear the fan in the back running because I've just driven you know 35 mi whatever it is the van is running after October I won't hear that fan running when I pull into the my driveway or to a service call It's few and far between because the weather's gotten cooler I guess. And I do travel when it's real hot with the air condition on and the windows up so that cool air is getting drafted back to the back of the car across the battery etc. It seems the windows down and regular air flow even on a 75 or 70° day seemingly is not sufficient because the fan is put on pretty quickly when the air condition is run I get a lot longer runtime until the fan comes on obviously I would think. So the Prius is one of those cars where windows down and window ventilation is definitely not a good thing put the windows up and put the air on.

 

What procedure were you following? One for P3000?

P3000 is a generic code that the HV control ECU reports. (It can mean "hey, a little bird told me about something going on back at the battery ECU, you might check that out." But because the code itself is reported by the HV control ECU, they can't leave that ECU completely off the suspects list.