Hybrid System Warning Light + Yellow Brake Warning

1. Make the Prius READY, then remove the inverter coolant reservoir cap, in order to better see whether you have fluid turbulence within the reservoir. If you do not see this, then you need to have the inverter coolant pump replaced.
2. If your car has a driveability problem again, note the exact warning lights or else take a good sharp photo of them, and post.
3. I don't recognize the tentative code that you listed. If you have a problem again and have the DTC read, make an accurate note of it so that you can post. There are literally hundreds of possible codes that might be registered, and the format is ANNNN where A is an alphabet character such as P, C, B or U; while N is a hexadecimal character from 0 - 9 and A - F.

 

Having the correct code would be a helpful. Any chance the mechanic put it in writing?
Also, sorry for confusing the issue talking about the hybrid battery earlier.

 

If you've read the voltage directly after charging it'll be temporarily higher. If you drive the car for a few days, or maybe turn your headlights on for a few minutes, then check, you'll get more realistic reading.

I believe this temporary higher reading is called "surface charge" something like that. In a nutshell it's a short term spike due to the charging, not going to last though.

12.6'ish or higher what a good, 100% battery will show. If your battery is quite old I'd just change it regardless.

 

A P3000 is the generic obdII code for "Battery Control System", but generally there are other more specific codes to go with it. Unless they have the correct scanner, they may have access to the hybrid-specific codes.

 

By unhooking the 12v battery, you will clear most codes.
But if they come back, then you have a recurring problem

 

Pay them for the diagnosis and get the codes in writing.
Report back here and don't feel like you need to make an immediate decision.

 

The dealers will offer to replace the wiring harness in the event of any unusual electrical fault that is outside of the normal troubleshooting tree in the service manual. That involves replacing huge amounts of connections that are just fine, to repair one that isn't. It works for them because it involves an exorbitant bill at the end.

Where are you located? This is a job for an independent shop that will clean up a bit of corrosion and get you back on the road again. Probably the battery has overheated at some point, and that has spawned the cascade of errors you mention. If you can get power to the fan, you might be good to go.

 

I've run into similar situations where the only solution the dealer could offer the customer was complete harness replacement.

Instead I was able to offer a less invasive and less costly solution. I cleaned up and resoldering of small portions of corroded connectors.

It really depends how bad things are. What you are describing does sound rather ominous. But that could simply their opinion based on their expertise. If you are comfortable with soldering, heatshrink, etc maybe you can dive in and get the job done. It may take quite a bit of labor, but at least you will not be paying an hourly fee.

Take some photos and post them up or send them my way via my email. I'd be happy to comment on them.

 

See post #19 here:
12V battery replaced with wrong polarity | PriusChat

That will give you a start regarding how to remove the main relay/fuse box. As you might expect, this is not a common problem.

Neither the Toyota factory repair manual nor the electrical wiring diagram provides information about how to remove that box.

 

Do you really think the whole things needs to be detached? Does it really look horrible across every bit of the fuse box?
Otherwise maybe you can deal with only the affected circuits.
In order to get a better feel for things I really need a couple of pics posted, or send them to directly to my email.
[email protected]

I know of a hybrid guy in NY area that I could reach out to you as well. (He is doing a Camry Hybrid battery install that I set him up with.) He's over in Staten Island, though.

 

1. You need to replace the fusible link. That part provides substantial power to several circuits and lives in the ~5" long whitish box. That box is supposed to have a clear plastic cover. Since it does not, your photos show some pretty nasty corrosion within. The link that I earlier provided in post #32 explains how one member did that replacement, which is not going to be an easy task.

2. If you are not going to replace the relay/fuse box, you at least need to get a suitable cover for the existing box to prevent further corrosion damage. Contact autobeyours.com to see if that vendor can sell you a relay/fuse box cover.

3. I suggest that you need to remove each fuse and relay in the relay/fuse box, one at a time, to inspect the socket below each part. Use electrical contact spray cleaner to clean off any corrosion that you find. Use an ohmmeter to measure continuity of each fuse before replacing it.

4. Regarding the traction battery fan, that receives power from the 10A BATT FAN fuse and the Battery Fan Relay. The fan speed is controlled by the battery blower motor controller and the traction battery ECU.

5. You need to obtain Mini VCI (which runs on a Windows XP or Windows 7, 32 bit OS laptop) because that will allow you to retrieve DTC that your car has logged. Since five DTC were reported by your dealer, you should not expect that your car only has one problem. You'll also need to subscribe to techinfo.toyota.com to obtain access to the factory repair manual and electrical wiring diagram for your model year. This will help you to interpret the logged DTC and figure out what to do about them.

6. I hope you didn't pay much for this used Prius when you bought it last year, because electrical problems can be very difficult and costly to find and repair. Good luck.

 

Here is another thread from Prius expert Paul Guzyk that discusses a blownfusible link with a close up pic.
How to change Fusible link under hood | PriusChat

Paul provided part number, a source and pricing.

The last post in the thread tells how one user temporarily bypassed the fusible link. Yipes! Would it work. I suppose. Kinda dangerous? Yes.