3 Failed ECUs? (2006 Prius)

I have recently taken my 2006 Prius to the dealership, but I'm getting some strange information from them and I think I need some advice before moving forward.

About 6 months ago the car threw the red triangle warning light and would refuse to go into gear. After a little checking I found the the 12v battery was weak and jumping or charging the battery would allow the car to go into gear and shut off the warning light. It would do this about once a week or so, so I finally replaced the 12v battery and haven't had any issues with it for the last 6 months. . . A week ago it gave the same warning and again wouldn't go into gear, only this time the 12v is fine. I tried near everything to get it into gear but it looked like I would need to have it towed. A couple days later when I was cleaning it out before having it towed, I decided to try one more time and sure enough it went into drive! The red triangle was still on but the dealership is only a few miles from me so I drove it there.

Now comes the part I'm struggling with. After 3 days and $450 worth of diagnostic fees they call and tell me not one, but three ECUs need to be replaced to the tune of just over $3000 (with labor). The Transmission, HV, and Power Control ECUs are all in need of replacement. As you can imagine, I was a little surprised considering how I drove the car there on its own. In my experience computer components don't "go bad." They just fail. So naturally I asked about what codes were generated to point to these three components. . . no codes. Okay sure, so they must have removed them and tested the pins. They did not. They know that these three are bad because they are not responsive. I'm fairly hopeless when it comes to most things mechanical, but I am no stranger to electronics and circuitry. Something about this doesn't feel right and I could really use some advice.

I will concede the possibility that three computer subsystems failed simultaneously, but my biggest concern is that they don't have a clue as to why. I'm worried about putting $2000 worth of new components in if this may happen again.

Any input someone can give will be greatly appreciated!

 

That's really the heart of my concerns. I've asked at every chance and the dealership mechanic assures me that there are 0 codes to read. I'm highly skeptical about such an expensive diagnosis when they can't provide me with any information as to why. Also they still have the car now. I'm regretting not getting the equipment to read the codes myself before taking it in.

 

Thanks for all the advice! It's reassuring to know that its not just me being paranoid. I wish I hadn't shelled out $450 for them to tell me nothing, but that will be between me and their manager on Tuesday.

Hopefully I'll be able to get it in to gear again so I can at least get it off their lot. I'll keep this thread updated as the story unfolds (and hopefully when I get the codes!)

As an aside question looking towards the future. . . When I was in Pensacola FL, nearly every mechanic would work with my Prius no problem, but here in Auburn AL its hard to find one that will do anything more than change the oil. Should it turn out that I need to replace an ECU, would you advise against DIY? I'm pretty comfortable with vehicle and/or electrical DIY and can easily manage removing the dash, airbags, etc. However if it really is the HV ECU or something more difficult to get to then I'm not too sure.

 

I had a meeting with the manager at the dealership this morning and was able to get some more information. I'm not sure why they had insisted that there weren't any codes generated, but the manager pulled them up and showed me and it doesn't look good. C2300, C1310, and P3102 were thrown. Since they've checked the wiring and other usual suspects it would seem that those ECUs ARE the problem! I'm still not sure why I was able to drive it though. With its history of 12v battery failure I will have them check it again, clear the codes, and see what happens after that but I think the 12v is probably fine. I'm not sure if I want to risk putting in used ECUs either.

Any other ideas, or am I the proud owner of a large paper weight?

 

I've attached the 6 page algorithm the mechanics followed to reach their conclusions. If nothing else perhaps others will find this information useful. There seems to be some discrepancies between what they told me they did and what they actually did, but I don't think the person they had speak with me actually worked on the car himself and perhaps misspoke. I still think I don't fully understand all the parts of the flow chart though. The final step, for example, says to "Go To Relevant DTC Chart" if DTCs are output. They circled that no DTCs were output so replace all three ECUs. . .

 

I've looked and found some good prices on replacement parts. If that's what needs to be done then I will certainly be taking that route.

The VCI I ordered just arrived today. Unfortunately I don't think I'll be able to get the car back until this weekend. And that is a very generous offer that I will gladly accept! It may be a few days before I have more information to post, but I won't leave the forums with a cliff hanger for too long.