A Dead Pri

Hoo boy... This is a brahma...

So about a month ago I was faffing about putting a new USB/Cigar lighter point on my T3 Prius, if you are aware of this bum basic model the only Cigar lighter socket is in the centre line arm rest box... I needed one on the dash for my satnag so I set too, stupidly I had the radio on, net result eventually the 12V battery went flat and that is when the fun started.

Now. I put the "magic key" in press the start button and the dash board lights up for about 1 second then it all goes dark. If I hold the start button in eventually the centre screen will light up but will show the traction battery level meter as completely empty. And this is where I went down a rabbit hole.... I firmly believed it was because I had killed the 12V battery that this effect with the dash was happening. So I checked every single fuse, took the dash apart again (getting quite good at this) to make sure I hadn't left something disconnected. Because I thought in my poor addled brain the last thing I did is what killed this thing. Did I mention the Rabbit hole? What's even worse is I can't get anything off the OBD2 port either, it seems to kill that stone dead too. Also the "magic key" won't latch in place, lots of bleeps though, some of them from the car... But a totally black dash but the radio still works. If I try and work the wipers they will move about 1/4 of the screen then stop until I press the start button again.

I even bought a new 12V battery for it just in case. It's not that.

I took the traction battery pack out, stripped it all down, cleaned the copper links, they were in a state so it was ready. Charged and discharged all the cells, recharged them, balanced them, finished up with 218V across the terminals before the relays and as far as I can tell a pretty healthy battery for an 18 year old Prius with 160,000 miles on it's odo.

It will run a 240V 60 watt light bulb more or less for about 12 hours, then I recharged it all again, I'm getting good at whizzing those 8mm nuts off I can tell you. I charged it with two decent quality "Hobby chargers" one cell pack at a time, they are all good.

So this is where I am. I put the Orange plug in and push it down.

I put the "magic key" in and push the brake pedal down and press the start button.

I get a dash full of the usual lights for about 1 second then the "FNRP" boxes all lose their writing and turn into boxes then it all goes black.

If I take my foot off the brake and hold the start button in for about 3 seconds the "Prius" screen will come to life, but none of the buttons on the touch screen work. At all. nada. And the graphic for the battery shows a white empty box.

So I have read up, watched Youtube videos all night, and all that I have gleaned from this research is that when the start button is pressed the Hybrid brain is supposed to send a signal to the Battery control "brain" to turn the relays on to test all the Orange cable work, and control circuits if it's all ok it allows the car to run as normal, if it finds anything wrong it seems to kill everything. Am I about right here?

Now the last major thing I had done was to have a new A/C compressor fitted and a regas/new condensor rad, the A/C worked wonderfull. So I think I maybe need to start from the battery, find the Hybrid brain, check every connection from there and see what I can find?

Or am I missing something stupidly obvious?

Help?

 

That's the bit I'm struggling with, if the car Hybrid computer checks everything else first before powering up...

So I have a few things to check once it stops raining here is South Enggland, somehow I don't think exposing the under bonnet power systems to torrential rainfall would be a good plan.

!2V battery voltages are 12.6v un connected, 12.3v connected so something is drawing current. It's a brand new Varta battery that I put on the battery conditioner for 2 hours before fitting.

 

You are chasing the wrong rabbit!!!!
The hybrid system has NOTHING to do with the car powering up. This is all controlled by the 12v system. Even if I removed the HV battery, the car would still "power on" all the 12v systems.

Ah. That's interesting. So is the dash powered by the 12v battery or the Traction battery?

 

What voltage do you measure for the battery in the boot, and again at the 12v "jump points" under the bonnet ?
Many Thanks for the welcome... I checked all the fuses using a test lamp off the "booster" point, never thought to check the voltage on the check point.... We have had some pretty severe rainfall on the south coast of England over the last few days so I haven't really been able to check under the bonnet. But I have a few more checks I can do now.

I found an electrical manusl online, something like 230 pages of it so I have printed off the bits I think are relevant to my further search.

Oh and I bought a battery conditioner charger from the US, just had to pay £116 extra customs charge, Ouch... That's die tomorrow.

I also run a Lexus RX400h. I understand it more or less uses the same battery pack as the Series 2 Prius, but that's not a Rabbit hole I want to go down just yet... It's just gone over it's 200,000 mile birthday.

 

Just for fun pulled the big orange cable out of the back of the AC compressor and let it just hang there. What happens now? If nothing then continue with your analogy and work any bad grounding points?

Did nothing, still got the original fault. When I plug the OBD2 reader on it tells me it cannot communicate with the ECU. Must be an obvious clue, but which ECU are we talking about?

 

The apps I have used are Dr Prius, a Creader and a Autel Diaglink and a 2012 version of DELPHI.

All tell me they cannot communicate with the car's ECU. This is the bit I am trying to get to the bottom of now. If it can't communicate with the ECU then there is something obvious that I am missing.

That and the transponder key refusing to latch into place.

 

I still believe it has a lot to do with the transponder key not latching when it is pressed into place. If I can get to the bottom of that....

 

All the fuses are good, I'm beginning to suspect I have a brain not working for some reason. What I do need to do is make sure that all the fuses that should be live actually have a feed in the first place. So I need to make a test lamp. .

 

First thing I did. As I mentioned in the first post usually what you did last causes the problem.

 

Ok there has been a development of a kind.... I discovered that my test lamp has an intermittant problem, which led me down another rabbit hole, I was getting a voltage reading from my Fluke meter but apparently not enough current flow to light a 3w test lamp... I've been there before, chasing earths so again I went off on a tangent and wasted about half a day checking earths. The days aren't very long this time of year and I'm working outside.

So I've put the battery on charge again, and ordered a test lamp with a built in volt meter, and as soon as everything is back in place, decent weather and a fully charged battery I'll start again from the battery to the fuse board to the switches etc.
I still believe I'm missing something incredibly stupid.

 

Going to have to give up on this one I think and get it collected by the scrappy. It's too old to spend a lot of money on, and finding someone local with the right level of knowledge is a problem, even getting it to them will be a pain in the butt.

Never mind. At least I can say I had one once. Most unreliable car I ever owned.