Prius Gen 1 Issue (2003)

Sounds like you were in the right place then. Where the repair manual describes P3009, it pretty much tells you what the possibilities are, and it's very sensible to assume that is what they meant. The troubleshooting steps for the remainder of those eight pages then help you pin down which of the possible items it is.

 

Toyota Service Information and Where To Find It | PriusChat

 

Printed Repair Manuals can be found on ebay.

https://www.ebay.com/itm/385446247166?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=77jzihqgqim&sssrc=2047675&ssuid=&widget_ver=artemis&media=COPY

 

If you go that route, keep in mind that in addition to those two volumes, the Electrical Wiring Diagram is its own skinny separate volume, and so is the New Car Features manual, which is the one that explains what all the things in the car are for and how they do it. Sometimes the text in the two main volumes will seem not to explain enough, because they assume the background that's in the NCF.

Another option is to spend $20 for a two-day subscription on TIS and download them. In later years, that became more of a pain, because the manuals became native digital, and downloading involves spending a lot of your two days doing print-to-file section by section by section.

But the earlier manuals, and 2001–2003 may still qualify, were pretty much put online as big PDFs identical to the printed books, so a lot simpler to download, and you can collect the whole set for $20, and they take a lot less space on your phone or laptop than on your shelf. And you can text search them.

 

My gen 1 threw the same code. The local Toyota dealer made the same kind of "non test" and declared that there might be an HV problem. They wanted some huge amount of cash to diagnose it. At least the diagnostic charge could be applied to the repair if they found something. Sounds backwards, paying them if they don't find the problem... hmph.

When they did a real diagnostic, they found that the "electricity leakage" was not due to the power cable. The problem was that two of the battery modules had cracked open and were leaking electrolyte which was conductive. That brought the frame of the battery case up to about 1/2 of the HV voltage. Around 200 volts DC if I remember correctly.

The problem surfaced right after a trip that I made to snow country. I spent 2 months in Oregon during weather that was frequently below freezing. I suspect that the two battery modules cracked as a result of freezing.

The fix was to replace the battery pack. I opted to buy a new battery pack, as it was only $1300 and included a multi year warranty. At my direction, they cleaned the buss bar connections to rid it of corrosion, saving about $500. Once the new battery was in place, all the codes went away and the car worked fine until I traded it in on a Prius Prime.

 

The description for P3009, excerpted above, lists 11 possibilities for the trouble area. Finding out that it's not the power cable is good progress, meaning there are only 10 possibilities left.

That's a good description of what the problem was in your car, and an interesting guess about why they cracked. I don't know offhand what the freezing temperature for the potassium hydroxide solution is, but it can probably be looked up.

While that was the fix in your car, the battery is also but one of the 11 possible trouble areas. For some future reader of this thread, replacing the battery will be a win if their problem is also that one, and not a win if their problem is one of the other ten.

(Well, ok ... several of the other listed trouble areas are things that are physically part of the battery assembly, so they would all be new if a whole new battery assembly were put in. On the other hand, mostly Toyota has been selling partial battery assemblies, where you would swap a bunch of those other things over, so you'd still want to know if one of those was the culprit instead.)

The way to proceed that's always a win is to follow a troubleshooting sequence like that given in the manual until you know which item is the actual source of the leakage current, and then fix that.

 

That seems like the right plan for the circumstances.

 

I agree 100%

Unfortunately I've come across a LOT of mechanics (including many other makes / models) that prefer to replace parts without following the troubleshooting sequences. Even worse is the tendency to replace multiple parts without testing to determine which part is defective. That's the behavior that you should watch out for when the service manager tells you something similar to "The diagnostics indicate that we should replace the choke, clutch cable and head gasket. That's $3,599 including labor and disposal fees." **

** Yeah, those parts are not present on a Prius, but that does not always keep crooks from trying to sell them to you.

P.S. potassium hydroxide solution does freeze at the temperature that my car was exposed to.

 

While you can replace a lot of stuff yourself, that does not assure that a bad part was removed and that a good one was installed. Testing, on the other hand, will give you that reassurance. Some tests are as simple as disconnecting a connector and checking for the proper voltages or resistances on the connector's pins. The trouble shooting instructions tell you what to do and how to do it.

 

The code is about insulation leakage. Insulation normally has extremely high resistance, and "insulation leakage" really means slightly less extremely high resistance. To measure for that takes a specialized instrument for extremely high resistances, a megohmmeter or "Megger", which generates and uses 500 volts, and while you could obtain one (pretty much anything has a cheap version from China these days), if you haven't got a knowledgeable person to train you on its safe effective use, it's on you to at least seriously seek out and study that information.

You could do that, say, by ordering one online, and using the time while it ships to download and read Megger's publication "A Stitch in Time", which will give you much better information than will come with a cheap offshore tester (you'll be lucky if you get a page that shows how the batteries go in).

But as long as we're talking about tests that involve a bit of invested time and money and study, I'd return to the idea of investing some of that in studying the troubleshooting sequence in the repair manual. That will help you organize what you do with the other tools and toys so you get the best bang for the buck.

 

P3000 is an umbrella sort of code. It comes from the HV control ECU, up in the instrument panel, kind of the orchestra conductor for the car. It's saying "hey, the battery ECU (the one back inside the battery itself) just told me there's some trouble code action back there." We already know what that code is.

There are some INF codes with P3000 indicating what general kind of trouble the battery ECU was talking about. There are other INF codes for when it has to do with the HV fuse, the battery cooling, the discharge inhibition control, or a really weird voltage, and 123 is the INF code for everything else.

As for physically seeing the cause of a P3009, well, it doesn't cost anything but time to take a look. Some cases of "slightly less extremely high resistance" won't be visible, but of course a giant scrape with copper hanging out will also give you a P3009, and that you could probably see.

 

A: Yes, because the battery ECU is what has the job of monitoring the whole high-voltage system for electrical leakage.

Another option, even if you already spent $45 on the printed versions, is it's still only $20 more to sign in to TIS and view or download them online, for something to do while you're waiting.

A few more question (From the page you posted previously on possible causes of the 3009 code.)

I know that answer: yes.

Those are things I'd have to go look up. Offhand, I know the big orange wire pair running from the battery to the front of the car is usually called the frame wire. The collection of busbars and 20 skinny wires running to the battery ECU is called the number 2 frame wire. That leaves two fat wires connecting the ends of the battery stack to the main relays, and the ones from the middle of the stack to the service plug. Probably best to just see if the manual points out what they're calling the main cable.