RED TRIANGLE AND CHECK ENGINE LIGHT!

If you can get to an auto parts store they might be able to read some of the error codes.... Once you get the error codes you can do a google search with "priuschat and error codes" in a Google search and start reading threads to figure out next steps. Once you get a sense of it, come back to this thread and post what you learned and we'll add more details.

 

You need to have the car scanned for codes with a Prius-aware scan tool. You can have this done at a Toyota dealer, where it will probably cost either an hour of labor (about $100-$120) or a diagnostic fee (maybe $50-$60). You can also have it done at a good independent mechanic that specializes in Toyotas - the cost will probably be a little cheaper than the dealer. Before you take the car to an independent mechanic, ask if they have Techstream - this is the Toyota software that knows how to talk to a Prius. If they don't have it, try another mechanic.

You can also do it yourself. The easiest way is with a computer that runs 32-bit Windows XP (32-bit Vista or 7 is probably also OK), a "Mini-VCI" cable from Amazon or Ebay for about $25, and a copy of Techstream (which is available here on Priuschat). Basically, you use the Mini-VCI to connect your car to the computer, run Techstream, and ask Techstream for the problem codes.

The "generic" scan tools that many car parts stores and some mechanics have will read some of the trouble codes on a Prius, but may not be able to read all of them. The !-triangle and !-car are often associated with the hybrid control system, and a "generic" scan tool won't always be able to talk to that system.

It probably won't hurt to go to a car parts store and ask for a free code scan, but they may not find any codes, or they may only find some of the codes. The price is right, though. I know AutoZone and O'Reilly offer this service, and other parts stores may do this as well.

Once you have the problem codes, preferably from a Prius-aware scan tool, post here with what they are.

I hope this helps!

 

Next step is to do Google search with search terms: "p3125 c1259 PriusChat" and start reading while doing lots of critical thinking... There's plenty of comments in these forums that can throw you off...

 

P3125 is "Converter and Inverter Assembly Malfunction". This is the box under the hood with the big square silver cover that says "Toyota Hybrid System" on it. Basically, it chops the DC from the traction battery into AC for the electric motors in the transmission when you want to go, and rectifies AC from the transmission back to DC for the traction battery when you stop.

There is probably also an "information code" associated with P3125. A Techstream scan tool can read this code. Torque Pro on a smartphone, coupled with a Bluetooth OBDII adapter, may be able to read this code. The scan tool at the car parts store probably can't read this code.

The reason the "information code" is important is that there are 36 pages of diagnostics for P3125 in the factory service manual. You can cut that down to 4 or 5 pages - a specific part of the converter and inverter assembly, or the wiring to it - if you know the information code.

Just swapping the converter/inverter assembly for another one is probably not ideal. It is uncheap, and some of the reasons for P3125 to set have to do with wiring harness issues that a swap wouldn't fix.

A simple thing you could check at home would be to get a strong flashlight and inspect the low-voltage connectors and wiring to the converter/inverter, as much as you can without taking anything apart. If you open the hood and look towards the driver's side of the converter/inverter, you'll see a spot with about four connectors, all in a row, on a bracket. Make sure those wires, on both sides of the connector, haven't been chewed on by a mouse or pinched underneath something else - things like that. Going one way from those connectors, the wires will disappear into the converter/inverter. Going the other way from those connectors, they will disappear into the engine room wiring harness. It'll be hard to see it all without taking things apart, but look at as much of it as you can.

C1259 is the brake computer complaining about the same problem as P3125. Since the hybrid system is part of the braking on a Prius, the hybrid computer tells the brake computer when there is a problem with the hybrid system that might prevent it from providing braking. The brake computer sets C1259 when that happens. The friction brakes on the car still work and you can still stop the car; you just won't charge the traction battery as you stop. Once you fix whatever is causing P3125, the C1259 code will most likely go away on its own.

I hope this helps!

 

I'd like to add that before you start poking around with the inverter, you should remove the orange safety plug in the back to disconnect your HV battery. Those orange cables you see connected to the inverter are under a high voltage that could electrocute you. There is a 3 step process to put the safety plug back in after you are done checking what you need to.

 

Congrats... Sometimes the hardest diagnosis are the ones that are related to the most common repair job... Everyone keeps thinking it's an easy fix, but they actually don't spend enough time to be certain that they know what's wrong with it...

 

Thanks for posting back with the diagnosis! That helps everybody calibrate their advice to the next person, and it also helps people who are searching the forum in the future.

 

I've never had one fail on mine so far, so I don't know for sure. I can guess, though.

Probably #1 on the list is that the wire(s) from the sensor to the circuit board inside the inverter are broken. Depending on where the break is, this may or may not be easily fixable. If it's in the middle of the wire you could splice or solder in a new piece of wire. If it's at one end or the other, that gets a little trickier.

The current sensor probably consists of a donut made out of ferrite (powdered iron, basically), with a big fatty wire for MG1 or MG2 running through the middle of the donut. Then, there is either a very fine wire wrapped around the donut for several turns, or a Hall-effect semiconductor sensor embedded in the donut. Both ends of the fine wire, or both wires coming out of the Hall-effect device, go to the circuit board. Current in the big fatty wire induces a small voltage in the fine wire or Hall-effect device, which gets measured by an analog-to-digital converter on the circuit board.

With either kind, if the donut is cracked, that can affect the sensor reading... maybe if you hit a really big pothole, or accidentally dropped a hammer on your inverter or something, that might happen. With the fine-wire kind, about the only other thing that can happen is #1 again - broken wire. With the Hall-effect kind, the Hall-effect device might have failed... because it's old, because you drove 10 feet from a lightning strike, or because the voltage regulator for the logic inside the inverter temporarily or permanently went bad and is putting out too much or too little voltage.

Outside of that, if the current sensor got coolant or oil in it somehow, that might screw it up. Without busting out the service manual, I think the current sensors are all in the "dry" half of the inverter, so if coolant is leaking into that part, you have a bigger problem in the inverter. If you somehow got steel or iron chips/filings/dust inside the current sensor, that might also cause it to read wrong... but for that to happen, you'd have to have the inverter cover open, and be grinding, filing, etc on some steel, over the open inverter.

Some of this is a little bit academic, because I don't think you can get the individual inverter components loose piece. You might be able to reverse-engineer it enough to replace them with something you can get, or buy another inverter that failed for a different reason and make one good one out of two bad ones. If you're playing this game, it's a good idea to keep a bicycle in the trunk, or at least carry a quarter for the phone booth make sure you always have your phone charged and with you, until you know your fix worked.

That's up to you. If the car thinks the inverter isn't working, you may not get any action out of the traction motors - you'll be down to about 75 horsepower from the gasoline engine, and you won't have any regenerative braking. If you're driving on city streets, the lower power is probably not such a big deal. The regular friction brakes will still stop the car, but the ABS might not work, so be careful if it's wet, snowy, or icy. Out on the Interstate, it depends on the local traffic and your driving style. If you have to do 85 mph in the slow lane just to keep up, or if you often find yourself having to stomp on the gas so you don't die when a big chrome RENILTHGIERF looms in the rear-view mirror, then you might want to stay off the Interstate with it.

 

hello Prius owners,

I just got a 2006 Toyota Prius with 93,000 miles for $4,000. A deal that seemed too good to be true, so I bought it. 2 weeks later I get a check engine light, the triangle of death, VSC and the breaking light system. The following codes I received were:

C2318
P3000
P0A80
P3014

I was hoping I didn’t have to change the battery since I didn’t want to spend $1,000+ on parts. I also noticed from other forums that dealerships are asking for $4,000+. Anways, any advice as to what I should do? Most likely looking for the DIY route. Thanks for your time!

Ps. First time poster

 

This saved my life man! I had COMPLETELY forgot to push it down