Roommate's Car - P0A09 - Inverter Replacement?

I think that's the DC to DC converter that charges the auxiliary or 12 volt battery. That's on the bottom of the inverter and can be changed but once you take the inverter out to do that change getting that bottom plate off is quite messy it gets deformed etc You can run around and probably find a Prius inverter for the hybrid synergy drive 06 to '09 or '04 to '06 for probably near free from a local whatever junkyard place where people pile up metal junk cars etc find it on Facebook marketplace for $30 just to get it out of someone's way If you're in the southeast United States near North Carolina come by my house and what have you they're very stout well made rarely go bad a component went bad on the bottom and not charging the 12 volt battery like I say in a real mechanic shop world they would heat up the bottom plate pull it off and replace the DC to DC converter part whether it's from another vehicle or new don't have a clue If you're going to do that why not just use the hole inverter save yourself an hour of scraping the plate off the bottom like I say rarely are the inverters bad there are a couple of components on the inverter that can give you some grief and the 12 volt charging part of it is one of them but this is also pretty rare you want to read the codes with a capable tool and make sure you look at the freeze frame data and really see what you got write the codes all down have everything in order clear the business get the car to restart when the car is running what do you see on the 12 volt terminals with a test meter 13.5 to 14.5 then that thing is working You're moving on to something else check for the battery isolation fault with your test meter now that you have it out just to rule it out.. aha!

 

Take a look at this post. There are two signaling circuits between the DC/DC converter (contained in the inverter assembly) and the HV control ECU. They're called NODD and VLO.

Try to get the INF code for your P0A09. If it's 265, it's about the NODD circuit. if 591, it's about VLO.

Check the wiring before replacing the inverter. I don't care how cheap they are on eBay, nobody likes replacing a big heavy $$ part and then fixing a wire.

Can you edit your thread title to say P0A09 ?

 

So what is that actually mean the DC to DC converter inverter for the 12 volt battery is not receiving enough voltage from the HV battery to convert to 12 volts? That seemingly what the code description seems to imply I am no fancy electrician or engineer so there you go But yeah there is some wires that come out of that bottom cover that go into a what gray plug that we were just talking about trying to remove the other week I think it was here in Prius chat so I guess where that goes is probably back to the battery the 12 volt maybe would be a good guess as it's coming out the back of the inverter towards the firewall and going like those orange wires that go down and all the way back to the battery the HV battery so yeah if those wires coming out of that gray plug or what have you or damaged or something not sure exactly how but that wouldn't be good And yeah the inverters heavy It's no problem to undo and take out Make sure you undo the plug in the battery in the back before you start all that you're going to have to undo the lid and undo the bolts out of the big orange plugs and pull them through and a few other plastic plugs and clips and the half circle grommet needs to be lifted out and laid in between the fuse box and where your inverter sits and the bolts got to come out and all that so to even work on that DC to DC thing You've got to get the inverter upside down or to the bottom of it.

 

I never wondered why no P0A08 ... you have a P0A09, they're separate codes, they don't have to show up in pairs or anything. Just because somebody else in another post had a P0A08, you don't have to.

For the P0A09 that you do have, though, it is strange that you can't get the INF code. That would tell you whether to look at the NODD wire or the VLO wire. If you can't get it, well, just have to shrug and look at both.

It's not much use to spend time on "seemingly what the code description seems to imply". Need to look in the manual and it says what the code means. P0A09 is about one of these two wires (depending on the INF code) between the converter unit and the HV control ECU.



INF 265 means it's about the NODD wire. 591 means it's about the VLO wire. Whichever INF code, so whichever wire, the code means the ECU thinks it might be open-circuited or shorted to ground.

 

And there would indicate the low power which I guess would be to supply the circuit?. But I would guess so That's what it seems to say in the code you haven't got the manual yet so I can't sit here and peruse and look through pages and pages at the moment the online people have all disappeared what have you with the manual posted up and then to do that with a PDF manual I have to go in and get on a big computer where I can put up at least two pages at a time but yes the factory manuals from Toyota or wonderful I've used them for many many many many years and they can sure cut your time from BS and around in the near half

 

You should test it. Yes, one of the connectors shown is on the inverter under the hood, and the other is on the HV control ECU behind the glove box. I don't think it's hard to take the glove box out for access, though I haven't actually done it in a gen 2.

Nope; that's what the orange service plug is there for,

But there are big capacitors inside the inverter that store charge. They are built to bleed off slowly. Give several minutes after pulling the service plug before you proceed.

And before you fuss with any of that, check the NODD and VLO circuits that your trouble code is about. Those are ordinary low-voltage auto-electrical circuits. They won't hurt you, and you can check them with your multimeter.

It's hard to figure out where you're getting this. There are two wires involved that run between the converter and the HV control ECU. One is purple and one is blue and they look like wires, and the ECU is saying one of them might be broken or shorting to ground. If we had the INF code and it was 265 it would be the purple one, 591 it would be the blue one. I'm looking right at the manual as I type this. Checking a circuit for a break or a short to ground is something auto electricians have been doing since long before Priuses. We don't have to make guesses about low power or what not.

 

Things might get a lot easier if you arrange your own access to the repair manual, so we can be looking at the same pages.

The inverter/converter assembly has both: high-voltage connections (those are all fat and orange), and also ordinary automotive low-voltage connections that will not electrocute you. You'll see connector C5 on it somewhere. It will have wires of several different colors, including a purple one at pin 4 and a blue one at pin 5.

The wiring checks the manual would have you make are with C5 unplugged from the inverter, and H16 unplugged from the ECU. You can unplug those without worrying about anything high-voltage. Those are the ordinary low-voltage control circuits for the inverter and converter.

 

Hold on a second I'm going out to look at an inverter that's sitting out in the yard for the purple wire business to see where it is.

 

I have the insulation cut back on the blue and gray plugs see blue wire blue wire with a white line no purple but a light green color and others I took a picture but that's not going to matter here.

 

Only purple wires I see are on the big plug that goes through the half round rubber grommet into the inside of the inverter that you unplug after you've lifted the lid and you're making ready to remove the inverter this plug would be undone it has a bunch of purple wires in it purple with silver dots and so on and so forth so I'm guessing that's where part of this is or something anyway yeah pretty cool.

 

If you look in Prof. Kelly's video, you can see the light gray C5 connector on the back. The one above, with the multiple wires.

The light gray one below it, with just one fat white wire, is the converter output.



I'm looking in a 2006 wiring diagram where the NODD wire, C5 pin 4, is purple. If you've looked at a different year and it's not purple, they may have changed the color. It happens sometimes.

 

I'm looking at an '05 tour loaded JBL car inverter The '06 I think is the next one up that goes 06 to '09 or something like that so I guess what I have is the '04 and '05 the short nose

 

Personally, I wouldn't buy a Haines Prius Manual. They leave a lot out.

 

No you do not want to buy the h a y n e s manual they're no longer what they were back in the '70s and '80s they used to be published out of the UK I think by a sparkford publishing or something like that I think somebody bought them up and turn them into light reading material what you looking for here is excerpts from the factory three book Toyota manual set and this well Chapman should be able to tell you pretty quick I think he mentioned it before there's like 16 pages for just this trouble so there's a lot you could be reading problem is everybody wants to charge you to read it and didn't used to be like this but everything now's behind the paywall there are some people running around with PDF copies of the real factory three book manual set some people hear sometime will post a link and then you can go read the 16 pages of serious stuff and there's no mistakes they go through it pretty pretty heavy duty-like and I guess my early inverter that purple wire is a different color I have a look to see what it's supposed to be or I don't know position 5 from position 8 in the plug Don't really care. Seems to me like the code is telling you that the DC the DC converter which converts the 200 and some odd volts down to the 13.8 to 14.5 is not sufficient whether the IC circuit or whatever kind of circuit is is gone bad that can't make that voltage so the output is low I think that's what it said in your original code in the text not the numbers so I guess you could get lucky in a wire might be melted bad something seems to me though where the wires are going is not really a very clear path for a lot of melting and hullabaloo with the wires but hey anything is possible in this world so I guess we will see. But I think most of the times that I've read about the DC to DC converter for the 12 volt battery charging usually people are opening up that glued gold plate on the bottom of the inverter and they're changing out that circuitry that's in there because it's non-functioning I don't think it normally seems to be the wiring but it's been ate up by an animal or some such type of thing. There have been people here before not that it matters that wound up changing those internals or they just drop on another inverter The generation twos are pretty stout in the inverter end of it they're nicer than the ones in the generation 3 I think but that doesn't really matter out of the cars we've had here nothing is ever pointed because we need to do anything with that silver top inverter everything else has happened except the blown engine but the inverter only got to move it out of the way to work on the brakes and put it right back not saying that it can happen but these have a very low rate seemingly of failure and people with the generation twos aren't in such a big hurry to change it like some over in the generation 3 they'll slap these things off and on as fast as you can undo the wiring of course there are some recalls for those.