Rebuilt 2006 Prius Battery

Friend let me borrow a "better" scan tool and it threw up the same warnings but pointed out that my battery was only at 11.1v instead of the 12.4 I charged it to and it went down to 10.2 when the car was turned on in standby mode. It also stated that my ECU voltage was 0% but I'm not sure if that means the ECU isn't getting power or the ECU just isn't registering. I tried erasing the codes but the damn car didn't stay alive long enough for the tool to do it's thing. I've got the battery disconnected and on a 500ma float charger till in the morning. Hopefully 10 hours will do the trick and it's not so low that it won't just discharge the battery thanks to the float feature.

 

Does anyone know what's up with Toyota dealerships wanting $700 for the battery computer when it's selling for $50 online? Am I missing something?

 

If anyone is interested I didn't get hit by a bus. I'm waiting on my new control unit to come in. Probably thursday.

 

I think you're right. I'm really crossing my fingers that this new ECU is my magic fix. I'm out of ideas after that.

 

Well fellas. I think I have progress. I bought a new ECU and after clearing the codes I went from 6 warning codes down to just 1:

Scanner: Innova 3100
Error Code: P0AE0 - hybrid battery negative contactor control circuit high
Corresponding DTC Code: P1E03 - told me to look it up but I can't find anything on it.

I dug into the P0AE0 code and my ECU volts still sit at 0%. But once again I'm not sure if that's because it's shutting itself off because it detects a problem, if a connector is burned out, or if it's another component alltogether.
I know my contactors are okay because I tested them on a 12v source externally so it seems the only component left in this dance is the precharge contactor. That's assuming that the arc didn't fry anything "ahead" of it's connection, like the other ECU (terminology) unit in the glovebox.

These workthroughs have been very informative:
Click here for the webpage 1

Quick pic of my suspected culprit.



I'm about to try and test the Precharge relay, Contactor Relay Control Circuit, Main Relay,..... whatever the hell the name is! After that I may take it out and take it to the dealership and see if they have a replacement. If I don't get it running today is Tow-Day. I feel like I'm right on the edge of figuring this out. With 90% of the detective credit to you guys. Please let me know what you think guys.

Brian

 

I'm officially at a loss. I tested the relay and found it's model number.


RELAY, SYSTEM VEHICLE. BATTERY & BATTERY CABLE (PRIUS (NHW20)). TOYOTA Prius 1500CC 16VALVE DOHC EFI (2004 - 2009) # G384147020


I tested it with a 12v source and sure enough it clicked and closed it's circuit. I don't know if this relay is somehow different from the HV ones it controls but I'm out of ideas. Only thing I can think of is that it's the other ECU inside the glovebox or god forbid a problem with the inverter. I'm scared to get it to the dealership because half the time the technicians don't know how to work on HV systems and always just opt out to replace everything instead of finding a specific problem to save money. Does anyone have another option or path?

 

Further details on that code were
P0EA0-228
Which returns "Open or +B short in SMR3 (CON3) circuit"
Problem area: Wire harness or connector, Hybrid battery junction block, or Power management control ECU

Found a good test step through
GSIC - Global Service Information Center

I'm thinking it's the ECM behind the glovebox. Thoughts?

 

Okay these are my thoughts

Battery ECU: Good, since I replaced it.
HV Relays: Tested with 12v source
Resisitor: Had continuity
ECM: No way to test but I figure I'd be getting a buttload of DTCs if it were bad.
Wiring: All tested for resistance and continuity and checks out
Main System Relay (pointing to in prevous pic): clicked but not sure if working right
Auxillary Battery: Replaced with a high quality 12v.
Inverter assembly: No codes on it so assuming fine.

I even switched the voltage contactors (since they're identical) to make sure it wasn't a bad relay and system still stated that the Negative Control Circuit was high. So I know the voltage relays are good.

The only thing I can think of is the Main System Relay isn't passing the voltage on each side of the negative contact. At one point I was thinking it could be the HV Control (ECM) was malfunctioning and not seeing that the relays were getting proper voltage, but I theorized that it was unlikely the ECM was malfunctioning with JUST that small thing. The only other things it could be are things I don't know how to test, like preboost/postboost voltage and the health of that small white resistor.

Taking it to the dealership is desperation because those guys tend to not want to troubleshoot but just to replace which is easier for them but often times unessecary and increadibly expensive just like replacing the entire battery block ($3000) instead of the single bad cell in a battery block ($50). I'd love another option. Ideas?

 

I can't vouch for the continuity of the contacts. I figured if I heard it clicking it's circuit closed that that all was well. that may have been wishful thinking. I did end of testing the resistor and it checked out at it's rated 20 ohms. It's all in the hands of the dealership now. I figure they'll figure out what's wrong and I'll just fix it myself since they charge unreal money for things you can get for 1/10th the price online.

When I unhooked the HV leads I marked one with another color tape. Honestly though it wasn't even necessary since they're hooked together and quite stiff. I don't think I could flip them if I wanted to. Good suggestions though. I really wish I could've gotten it back working but I can only take so many dirty looks from the wife.

 

When I tested the the contactors I had a multimeter in continuity mode attached to the circuit leads. When I applied my 12v current the leads clicked and the multimeter toned for the completed circuit. After removing the 12v the tone stopped and the contactor clicked open. So I measured for continuity in the closed circuit and to make sure the coils were clicking shut with a 12v source.

That being said I had a real make-shift was of doing this so it's possible the dealership may see something I didn't. I just hope the HV tech isn't one of those guys who wants to replace the engine because the spark plug is bad.

 

IT LIVES!!!

The dealership technician said he made sure all the connections were solid and cleared the codes and it powered up fine. Only charged me for 2 hours of work (test driving and such).

I can only assume that since my scanner was only throwing back one error code that the dealership scanner, which is most likely a higher quality, was able to see and clear many codes that I couldn't. Which also begs the question of, has this car been fine for a week and I was just unable to reset it's codes? I replaced the ECM but it may be a possibility that after the arc it just needed code clearing and that ECM might have been fine too.

Ah well, I've got the car reassembled and it's driving great. Had I not carelessly arced the leads I would label this repair as pretty dang simple and cheap. Thanks for all your suggestions and help and hopefully my problems are over.

Thanks,

Brian

Time Spent: 13 days
New ECM: $75
2 New Cells: $110
Dealership: $200
Total: $385

Dealership Estimate: $3500
Online Replacement: $1200
Money Saved: $815 - $3115