Hi everyone, my 2005 prius with ~140k miles, suddenly stopped working with no warning when leaving a parking lot. The triangle of death, check engine and exclamation point lights all lit up. At the same time the engine started revving more than it should have with little or no power going to the wheels. It would still turn on and off and go into drive or reverse but aside from the engine revving the car stopped moving. I used a couple different OBD2 readers after getting it towed home and got two sets of fault codes. The Innova 3120 reader showed these codes: POA60 (twice), POA78, and POA7A. I then tried using a Launch professional 123x reader which gave these codes: POA60 (twice), C2318, C1241, C1259, C1300, and C1310. I've tried to do online research to figure out what all of these codes likely mean and I'm thinking its all related to the inverter, although some codes refer to the hv system or auxiliary batter, I'm thinking problems with the inverter would affect those systems and possibly throw those codes. I have previously replace the hybrid battery with an OEM replacement about 30k miles ago and replaced the inverter cooling pump about 10k miles ago. I just pulled the car apart to get the the inverter and see if there was any obvious connection issues. I didn't think to check the inverter cooling pump before that but since the codes didn't refer to over heating I'm thinking that is an unlikely cause. Everything in the inverter looks pristine with no corrosion or obviously faulty connections. Any advice would be greatly appreciated. I tried to look up diagnosing problems with the inverter but haven't come up with much and am pretty hesitant about the big voltage since I don't have high voltage gloves. I disconnected the 12V and hybrid battery safety plug and waited for any remaining charge to dissipate before removing the cover for inspection. Thanks so much for any help! I would love to have my car back ASAP
The best place to get information about what your trouble codes mean is from the repair manual for your Prius (more info), where you avoid the hazard of internet searches mixing you up with code meanings that apply to different cars. If you are going to do internet searches, it helps to know that there isn't ever a letter O in a trouble code; if you do yor searches for the correct codes P0A60, P0A78, and so on, using the digit zero, you are likely to get more and better search results. There are some codes that are pretty common knowledge around a Prius. C1259 and C1310 are codes from the brake ECU that only tell you it knows about codes from the HV ECU. So you don't worry about the C1259 or C1310, and just look at what your codes from the HV ECU mean (the P0 codes you've got here). C1241 and C2318 are both complaints about low supply voltage in the 12 volt system (one complaint from the brake ECU, one from the transmission control ECU, respectively). The "transmission control ECU" is the glorified name for a circuit whose job is to move one metal piece in and out of the "park" position. Those codes don't always mean a 12 volt battery problem (they can also mean wiring or connector problems delivering the power to the brake ECU or the skid ECU), but when you've got the same complaint from two different ECUs, that's a pretty strong hint to check the battery voltage. There might not be anything in particular wrong with the 12 volt battery, other than if the car will not go READY and charge it, you've just been pulling its voltage lower and lower all the time the car has been on. Probably needs a good long charge. The powertrain codes you have are for the motor current sensors for MG2 (P0A60), the motor control circuitry for MG2 (P0A78) and for MG1 (P0A7A). For all of those codes, there are a bunch of extra 3-digit "INF" codes that will tell you more about where to start the diagnosis, if you have access to a scan tool that can read them. The motor-generators are an essential part of the Prius transmission; if the car isn't able to control them, no power can get from the engine to the wheels, just as you've described. In Gen 1 and Gen 2, the inverter/converter assembly just contains the brawn of the operation, and the brains of MG control are in the HV ECU inside the cabin. Low-voltage wiring between the two carries the raw sensor data to the ECU and the PWM control signals from the ECU to the inverter. When you look your codes up in the repair manual (more info), you will find procedures for troubleshooting all that. It's pages and pages and pages; it will help you a lot to get those 3-digit INF codes, because with them you can eliminate a lot of those pages of troubleshooting without having to work through them, and you'll know which sections to focus on.
I think I have a similar problem with my 2008 Prius Touring. got 254k. now. the engine(inverter) doesn't seem to be charging the hybrid battery. Normally a/c drains battery to a point were ICE starts and charges to a safe level usually 3-4 bars. It's just not doing it. When accelerating to cruising speed or getting on the freeway usually ICE is on and Hybrid system provides EV power while battery is used and recharged constantly leaving 2-6 bars depending on rad conditions, etc. Now my Prius EV Battery only stays at one bar, critically low and car accelerates very slowly using only the engine power obviously. But when I accelerate depressing the pedal more than approx half way demanding power, the car doesn't respond and a "wooosh" like sound comes from the engine bay, and feels like if the "transmission" were slipping and not moving the car, to put it in some sort of way. What I find weird is that while I coast towards a red light it does charge a little more like usual, and it does charge normally while braking. So when I get off the freeway to a red light, I do get normal charge, and it doesn't deplete that fast, right after getting going the car responds and accelerates normally, the "woooshing" sound almost disappears even though I can still feel and hear it if I demand full power. I haven't checked for codes yet, but the check engine has come on and off. I checked for codes on last oil change before this started to happen and that code was related to the catalytic converter which I haven't changed. I don't have any other lights on, like the triangle of death or the Hybrid system warning light. I'm more inclined to think this is related to the inverter rather than the Battery pack. But then again, I'm no mechanic. Can someone please advice or comment. For sure I'll take it to a Toyota master tech hoping to get an answer. But a guidance is always welcome.
