My HV battery pack failed after 250,000 miles. I discovered a couple of leaky modules and the car (2006 GEN2 Prius) wouldn't start so I decided to replace it with a brand new (albeit aftermarket) pack. I believed all the horror stories about getting one from Toyota ($4500 - $7500). I should have checked first because when I did, (after I bought the replacement aftermarket) Toyota quoted $2800 which I would have spent the extra $1,000 for OEM. Upon installing it I still get C1259 & C1310. The A/C doesn't get cold and after starting the car and driving it for 5 minutes, the computer shuts down the hybrid portion of the system but I can still drive on just the gasoline engine with check engine light, red triangle of death, and red car w/vertical line through it shining bright. When I get to a stoplight, I turn the car off, then start it again and it will recharge the battery for another 5 minutes. I suspect a corroded hybrid control ECU connection or faulty PCB board inside the hybrid control ECU module, which I have actually fixed before on another car by "re-flowing" the solder. I know I know....but this is what people with very limited funds have to do! My reasoning for this is that when I clear the codes, the system operates flawlessly and the battery performs well. It even goes into full electric mode as it normally would. Then after 5 minutes, with the battery indicator fully green, everything fine and for no apparent reason, the computer shuts the hybrid portion of the system down and the red triangle comes back on, etc.. I'm going to check the external wiring harness connectors to the ECU, make sure all of the internal solder points are firm, and if that doesn't work, I'll need to find a used one somewhere (e-bay?) If somebody could concur or has had a similar experience and could offer some guidance, it would be much appreciated. I'm certainly no expert here!
It would help if you could read the codes in the HV (hybrid vehicle) ECU and any other ECUs that have codes. From the symptoms you describe, I would not be surprised to find you have a P0AA6 with sub-codes 526 and 612. Let us know what you find.
If the battery ECU came with the refurbished after market pack, it should be covered under warranty. Talk to the place you purchased the pack and get it repaired or replaced. If you take off the covers or open the ECU, then you'll void the warranty.
Another thought, make sure the hybrid battery fan is connected, clean, and working. If the hybrid battery is overheated, the system will stop using it.
+1 on reading the trouble codes. You have the brake system codes C1259 and C1310, which is the brake system telling you it knows there are trouble codes in the hybrid system, so if your scan tool isn't showing you those codes, it would help to get access to a scan tool that will, or get the car to somebody who has one. Just to be clear on which ECU you are talking about here: there is a "Hybrid Vehicle ECU" (under the dash) and a "battery ECU" (in the traction battery box) and sometimes people mix the names up. Which one do you mean? (I don't often hear of corrosion problems in the HV ECU.)
There was the P0A80 but I believe that code is a faulty output. The battery pack isn't refurbed or reconditioned, it's brand new. There was also P30's but they change all the time. Last week it was P3017 and P3019. Those went away and now this week it's P3021-23-24. Which ECU would be responsible for outputting these codes, shutting down the A/C, and shutting down the hybrid system 5 minutes after starting the car? It has thrown so many different codes over the last 2 months that don't come back when I clear them. It's malfunctioning. Is it the one under the dash, or is it the one in the battery box? I'm convinced that's the problem. Let me know if you're not though because I'm just going off common sense. It's part #89890-47092. Which one is that?
It's connected, clean, and working but it comes on loud all the time whereas with the original battery it was extremely rare to ever hear it. Then, when I spoke with the sales rep who sold me the battery to tell him I was getting intermittent DTC's regarding weak modules, he said it must be insulated properly which is weird because it's not a li-ion which favors heat. Wouldn't you NOT want to insulate it so that it doesn't overheat? I'm going to look into that today. You could be onto something. No, it's the original ECU.
Do you happen to remember whether you found the one you reflowed under the dash or inside the battery in back?
It's this one: 8989047092 - Drive Motor Battery Pack Control Module. Electrical, Wiring, CABLE - Genuine Toyota Part
Ok, that's the "battery ECU", the one located aft in the car, inside the battery box. It's not the HV ECU under the dash.
