No READY light, no errors (P0000), replaced LV battery already

Bisco:
There is a 125A fuse but it protects the LV from reverse polarity jumps. In addition to being very careful when doing the jump (paranoid), I also pulled the white wire in the fuse box that fronts the aforementioned fuse. That shut everything down inside the car. The inference there is that the fuse is fine. When I reconnect the wire, then the internal parts of the car behave as normal (except, of course, for the inability to get to the READY state).

[edit] I thought this through a bit more... It turns out that the disconnect plug actually also houses a 125A fuse. However, that also ohm's out to be fine. I thought I'd add this little tidbit for others though. That disconnect serves *two* distinct purposes!

Jerry:
Thanks... I think I'll wait for the OBD from Amazon to arrive then.... As for the dealer. They are good and I trust them (thus far they have also exclusively serviced the car). The only problem is that it will cost me roughly $500 to get the car there (towed) and diagnosed. I am in the unfortunate position of presently being unemployed so I would very much prefer to *not* spend that money if I can avoid it. So... I'll eagerly await the UPS truck!

 

Thinking this through.... Removing the HV access plate to the inverter won't yield any information. The HV will be zero volts there because there are two relays in the Gen3 HV battery. One switches the positive leg and the other switches the negative. Those are what you hear "clicking in" when the ready light comes on. They are also what I hear momentarily energize when I see the ready light flash. But the point remains the same... They relays are de-energized so I'll not see any voltage at the inverter.

<sigh>

Now I'm wondering if the ground fault monitor is, perhaps, faulting. hmmm.

 

Actually, a fuse (generically) is primarily to protect the generating circuit from damage or fire. In the Prius' case, there are two different fuses, one for the HV and one for the LV. There may well be a fuse in the positive assembly at the battery (that would make sense) but the 125A one is buried deep inside (actually under) the fuse box. The large white lead is hot from the battery if you measure it, and the connecting post in the box is 0VDC. I know that LV 125A fuse is good because when I disconnect that lead, the whole car is essentially dead (no indicator lights, etc).

The "find" was that the HV disconnect actually houses a fuse in it too. I suspected as much as fuses are generally accessible in some fashion and that plug is the best place to put one. If you remove the disconnect and then remove the handle, you can easily pop off the orange plastic back. That will expose a 125A fuse there. This one makes sense because in an accident, one might crush/short the HV lines going to the inverter. That over-current scenario would burn the fuse in the disconnect, thus shutting down the whole system.

Anyhow, all of that might be of interest to someone reading this posting someday. Unfortunately, it doesn't help with my particular problem at all. At this point I've:

• confirmed my 12VDC fuse, etc are good
• confirmed my 200VDC fuse is good and that the disconnect is inserted properly
• confirmed my brake switch is working properly
• replaced my 12VDC battery (albeit there is still some question about the voltage the new battery is sourcing)
• confirmed that every fuse in the fuse box is good
• confirmed that there are no fault codes (with the ELM327 OBD2 scanner...)

I'm pretty much flush out of avenues that I can pursue save one. I have the new scanner on order (will arrive later today) and perhaps that will give me some better/more information than the generic ELM327 based scanner. Frankly, at this point I'm not holding a lot of hope.

On the positive side, I found out that my insurance will cover a tow, so at least that is covered. Sadly, the dealer will still charge me a diagnostic fee of $190. However, if it turns out that the inverter has failed, then I think that the killer $3500 replacement and the diagnostic fee would likely be covered under warranty. In California, I think the inverter/battery system is covered by a 150K / 10 year warranty.

Anyhow, I am presently waiting for the scanner that was recommended. I'll keep you guys posted as I suspect you would like to know how this all turns out and because someone else stumbling on this thread may benefit from the final answer. I'm not holding my breath on the last ditched scanner effort but I'm hopeful.

Alan

P.S. Despite the oddity with the battery voltage, I am tending to think that is not the problem. When I hooked my Honda Odyssey up for a jump (my desperation move... again), I was getting a good 13.1V on the service mode display but the result was still the same behavior as before.

 

Bisco:
Regarding the fob... There isn't a slot. However, one of the early experiments I performed was basically what you are suggesting. In the Gen3, one places the fob over the start button. Through inductive coupling, the fob behaves much the same as an RFID and it allows the START button to be pressed. However, I have the same experience with this approach as I do when I am just carrying the fob in my pocket. Good idea though!

Thanks,
Alan

 

rjparker:
Yep... I'm kind of coming to the same conclusion as you. If you think about the power on sequence, that has some tentative support for what you are saying... The system likely starts to come alive, which is why I see the READY light quickly flash and the HV relays kick in. The inverter *should* start to charge the LV battery too at that point (causing a bump in the LV voltage, which I'm not seeing... I could stick a storage oscilloscope on there but this is getting kind of ridiculous). However, I don't see the LV bump and the HV relays kick out almost immediately. If the power on circuit of the inverter detected a failure, then that would likely be reported back and cause the HV relays to drop. That is how I would design it.

Anyhow, the only part of this that doesn't fall into place is why I don't see any Pxxxx codes indicating a failure. That said, and as has been previously noted, my OBD2 scanner is really not up to snuff. Perhaps when I get the new one delivered this evening, I'll suddenly see a code that makes all of this firm up. We shall see.

Thank you for the thoughts. And, yes, I owe it to the community to post whatever experiences ultimately resolve this problem. I will definitely do that.

Regards,
Alan

 

Well, hooked up the Mini-VCI. It is a bit frustrating because it wants to connect to the server, which immediately invalidates the version because the current one (10.30.029) is obsolete. I had to turn off my network connection (forgot to do that originally) to get the software to work and now there is a counter wherein I can only connect to my car 25 times before I'll be locked out. Grrr.

Anyhow, the long and the short of it is that I'm still mystified. There are a ton more options but I (interestingly) don't see much in the way of individual cell voltages as you had suggested there would be (Jerry)[on edit: OK... I went through some YouTube videos and I see now how to record the voltages... still don't see much that helps me concretely identify my problems though]. More importantly, however, I don't see any real errors at all. For instance, the "power Source Control Live" looks to be the more relevant ECU to my needs. But the 'Number of Diagnosis Codes" value remains 0. I see the 'Shift P Signal Pulse' changing but the mismatch signals are always 'No', etc.

I left scratching my noggin a bit, feeling like I haven't really validated anything. That is frustrating. I'd have liked to have gotten a definitive indication that the inverter was dead or that I somehow neglected to follow some inane thing. But so far I can only hear the soft, lonesome sound of crickets chirping in the field (not really... I live in the middle of Silicon Valley!).

So... time to give up the ghost and have it towed to the dealer? What say ye?

Alan

 

Yep, I actually had done a health check but failed to add that to the post. I found something like 3 error codes total but they were all unrelated. However, because the health check queries against a central server, my run was hobbled a bit because my network connection was severed. I considered turning it back on but I was afraid that if I did so, I'd run into the (non-dismissable) dialog that wanted to force an update of the tool.

Anyhow, I think we are coalescing into common belief that this particular car is probably not something for which DIY repairs are possible. As such, I'll be arranging for a tow today and getting the dealer to get the thing going. As stated, replacing the inverter (if in stock) should be a pretty easy job. It looks like it only has about 4 cable and the coolant connections going to it. The unit sits on top of the whole engine so the repair shouldn't take long.....

I also agree @rjparker... My old battery was probably just fine. However, I can't return the new one now and the old one and I don't have another Prius. Seems like a shame but then again, the old old was 5 years old.... Maybe it was time anyhow to replace it.

Alan

 

I saw that teardown and it was interesting. I had to fast forward through parts, but I could have sworn that the guy said they replaced the whole unit only. My personal thought was that this was kind of crazy. Clearly some of the ECU boards on top could be replaced by themselves. Frankly, even the IGBTs should be replaceable, although it probably would take more time than it is worth to get to them.

Anyhow, because their is an extended warranty on the inverter, further DIY doesn't make sense. I think we've collectively determined that pretty much all avenue of the 12 LV battery being the culprit is probably gone. Although it was a good thing to pursue, it probably was a rathole. In the end, however, all is good and I give a heartfelt thank you to everyone who has helped and given suggestions.... I really appreciate it.

I'll let you all know what transpires with the dealer.

Regards.

 

@bisco... Indeed... And then compound that with the price of the inverter. Eek. That isn't a good thing at all.

I've done some inverter designs and am presently working on repairing some VFDs (essentially inverters) for CNC lathes. These are old machines that aren't really serviced anymore (I have industrial mills & lathes as a hobby). I have to laugh... The setups I work on are not nearly as nicely laid out as the Toyota. Then again, mine are for 5HP machines and the Prius motor is something like 70HP I think. Although the concepts are the same, I certainly don't have that funny silicon sealant stuff to dissipate heat

Ironically, it turns out that the tow to the dealer is free! First, my insurance will cover it but then, when talking to the dealer, they said they'd cover up to 50 miles if I purchased the car from them. So, at least something is going better today.