Red car w/!, charging error, VSC, ABS, (!), power steering fail in 2007 Prius after winter weather

I recently got stuck at the bottom of an icy hill in my 2007 Prius without chains. Eventually I got up the hill, but not without some considerable time spent spinning the wheels and changing steering direction too fast.

It drove fine after that until a few days later, today, when shortly after starting to drive (~5 mins after starting to drive), a tone sounded, "Problem" flashed across the display, and the following warning lights appeared:

• Red triangle w/ exclamation point
• Charging system error (red battery icon)
• VSC: Vehicle stability control
• ABS
• (!): tire pressure
• Red car w/ exclamation point: hybrid vehicle ECU logged a DTC
• Emergency brake light

IMG_0650 by Curase posted Jan 20, 2017 at 5:15 PM

IMG_0651 by Curase posted Jan 20, 2017 at 5:15 PM

On another thread, someone said this pattern of warning lights meant that "the skid control ECU is having a fit". I'm guessing my winter-weather indiscretions are to blame?

As I drove home, the power steering failed. It automatically shifted into neutral twice. The second time I shifted it back into drive, it seemed to have more trouble making the transition, like it couldn't get enough power to do so.

The car has ~190,000 miles on it. I bought it used. It's never been in a significant accident. I usually drive it at least every 2-3 days I'd say.

I ran the battery DIY outlined here. In ACC mode, the unloaded voltage is 12.0V (low). When I press the power button again without pressing the brake, the voltage decreased further to ~11.6V and then steadily decreased from there. When it reached ~10.5V, I turned the car off completely. I did not try to start the engine. Does this mean that the battery is getting old but is probably still good for now, but there's something wrong with the charging system?

Could it be an inverter coolant pump failure, as suggested in this thread?

What should I do? How should I diagnose the problem? What are the problem and the solution likely to be?

Many thanks in advance!

 

Important Info:

Thank you so much, andrewclaus and dolj, for your advice and expertise! I understand that regardless of whatever else may be going wrong, the 12V needs to be replaced urgently. However, I'm a full-time student on an absurd shoe-string budget, so I need to do the most important repair first. TBH, I really can't afford even one repair right now, let alone two.

That being said, I checked the inverter coolant pump in both IG-on and Ready mode and I did not see any turbulence. I'm not 100% sure whether there was any movement while in Ready mode. However, when it was in IG-On, I verified that the coolant pump fluid was definitely not moving at all. I shone a flashlight on the surface of the fluid, and the reflection of the beam was completely clear, so no turbulence.

Does this mean that the inverter coolant pump probably needs to be replaced?

Also, I realize this is a foolish question, but what are the risks of driving around a little longer with a 12V battery on the fritz? What's the worst that could happen?


Physics nerding-out:

Btw, the inadvisability of spinning the wheels in icy conditions makes a lot more sense to me now that I've reviewed static and kinetic friction, traction, the physics of aggressive groove snow tires, etc. as andrewclaus suggested (I'm studying physics for the MCAT anyway so I'm taking the opportunity to deep learn).

Several people have noted that this problem is unlikely in cold weather conditions. Here's my guess as to why this case may be an exception. When I spun my wheels, I released a lot of energy as work done by the car on turning the wheels. However, the car couldn't get traction, so the wheels didn't do any work on the road (Work = Force x Displacement, so 0 Displacement means 0 Work). Energy is conserved, so instead of doing work on the road, all that Work was lost as heat (ΔE = W + q). Most of the heat probably went to melting the snow, but a fair amount probably heated up the internal components of the car itself. Maybe that damaged the inverter coolant pump. Sound plausible?

 

Just checked. It says there are no open recalls for this vehicle.

I'm certainly willing and interested in fixing it myself. However, I have no experience and almost none of the tools, so I'd have to buy most of the tools. I'm also worried about making a mistake and killing my car.

In Ig-On mode, I can hear a faint, steady humming noise when I put my ear up to the side of the inverter. I'm not sure if it was the pump, the inverter, or something else. Definitely didn't hear any bubbling sounds or anything like that I associate with an aquarium pump, just that faint hum. Is that enough information to tell if the pump is drawing power, or not really?

I tried to raise the car up high enough that I could get under it to listen to the part itself directly using the lift I have for changing tires. However, when I raised it too high I heard a breaking sound, maybe from the lift or the under side of the car. Then I noticed it said "maximum working load 800 kg". I think the weight of the '07 Prius is about 13,000 N, and 13,000/9.8m/s^2 = 1,300 kg, so the lift can only support about half the weight of the car. I got worried that if I went under the car with the lift it might fail while I was under it and crush me, so I aborted that mission.

I will attempt that as soon as I can. We've almost gotten stranded a few times already because the car wouldn't start.

I just googled "motor electrical failure". I saw a list of risk factors for it, and I've got at least 3 or 4 of them, so you're probably right.

Also that makes sense to me that the coolant fluid would probably absorb most of the heat from the tires spinning. Now that I think about it, coolant probably has a specific heat about as ridiculously high as water's if not higher.

 

This quote from another thread about bleeding the coolant is giving me hope that my inverter pump might actually still be working:

"Open the hood and put your ear down behind the drivers side headlight. Take note of how quiet the inv pump is when its running. Like an aquarium pump. Remember that sound...tone."

I didn't really hear any noise at all when I was just standing over the open hood while in Ig-on, but once I put my ear up to the side of the inverter as described here, I did hear that quiet humming tone. I'm working on learning the procedure for bleeding the inverter coolant fluid.

 

Yes, it is.

 

For sure, and thanks for checking, all these terms and concepts are new to me and I'm a complete newbie.

 

Thanks.

This is my understanding of the situation so far, please tell me if this is right.

One possibility is that the pump is fine but there's a pocket of air trapped somewhere in the system which is resulting in no fluid flow through the system, right? If so, bleeding the inverter coolant system to remove the trapped air is the solution.

However, another possibility that can't be ruled out is that the pump itself may be busted, no?

I know that I should fully drain and refill the inverter coolant regardless, I'm sure it's overdue. But to start with, could I just bleed the system without replacing the fluid just to remove any trapped air? If that's really the problem, that should fix it, shouldn't it?

Here's my understanding for what the procedure for bleeding the system to remove air pockets without replacing the fluid would be. It's a modified procedure based a YouTube video. Does this sound right / like a reasonable minimum viable solution to start with?

1. Remove radiator cover(?).
2. Remove inverter coolant reservoir lid and place clean funnel in opening to reservoir.
3. Remove rubber cap on air bleed nipple to the right of where the hood latches in front of the inverter.
4. Attach plastic tubing to nipple and place other end in the funnel. The funnel end of the tube should be exposed to open air so that air bubbles trapped in the fluid will escape, and only coolant will fall back down the funnel into the reservoir.
5. Loosen the nut below the nipple with a 10mm closed-end (box) 12 point or 6 point wrench.
6. Press power button twice w/o brake to enter IG-ON mode.
7. Coolant should flow in a dribble from the end of the tubing into the funnel.
8. You can squeeze the hose going into the inverter, below the inverter between the inverter and the front of the car, to get more air out. You can squeeze the plastic tubing to increase the velocity of the air bubbles.
9. Once air bubbles are no longer visible in the hose and the pump isn't making any hissing or gurgling noises, gently just tighten the nut. Do not over tighten.

 

Thanks for telling me this. I was wondering about this because in the video I saw on replacing the fluid, the guy said there was a hissing or gurgling sound when there was trapped air, and I didn't hear anything like that.

I'll take a look at your pump replacement tutorial in a bit and see if I feel up to it.

 

I've decided to hand this over to a professional. I have to get back to studying. But this has been a very educational process. I'm very grateful for your guys' expertise and help. I'd like to start doing my own maintenance in a few years when I have the resources for it. It seems like a fun hobby.

In case anyone with a similar problem finds this thread, here are my notes about how to repair and maintain the inverter coolant pump system, including how to replace the pump and how to flush, bleed, and replace the coolant fluid. These guides apply to any 2004-2009 Prius (second generation).

This thread by Patrick Wong is an authoritative guide to how to replace the inverter coolant pump.

The third post on this thread is a procedure for flushing the inverter coolant pump system of debris. This is only necessary if the drained coolant contains debris. See Patrick Wong's notes in Post 7 before attempting.

Here's a fast and cheap method to bleed the inverter coolant system of air bubbles without using the plastic tubing that the standard method calls for.

Here's a video about how to replace the coolant fluid and bleed the system of air bubbles (standard procedure with tubing).

I wrote a transcript of this video for quick reference, which I've included below. It may be useful to newbies like me. Keep in mind that there may be mistakes in the transcript, so do not use it as your only source of information! If anyone spots any mistakes, please let me know and I'll change it. Required tools and materials are bolded.

1. Remove radiator cover. Search this thread to learn how.
2. Raise the front end of the car with an appropriate jack. Search forum if you don't know what kind of jack you need to do this safely.
3. Place a bucket under the pump to catch fluid.
4. A wrench with a 24mm socket or a 15/16ths socket (24mm is the best fit). Set ratchet of 24mm socket to loosen. Loosen and then remove drainage nut w/ bucket or plastic pan underneath. Keep top on reservoir at first. This prevents fluid from gushing out too fast.
5. Then remove reservoir cap to increase drainage rate.
6. When drainage slows to drip, blow on open reservoir to get last bit out.
7. Put back drainage nut using a torque wrench set for 29 ft/lbs w/24mm socket. Set ratchet to tighten.
8. Put a clean funnel into the opening of the reservoir.
9. Slowly pour pre-measured 0.5 gallon of Toyota SLLC coolant into reservoir. You'll need about 0.5-1 gallons of coolant.
10. Remove rubber cap on air bleed nipple to the right of where the hood latches in front of the inverter.
11. Attach plastic tubing to nipple and place other in the funnel. This end of the funnel should be exposed to open air so that air bubbles trapped in the fluid will escape, and only coolant will fall back down the funnel into the reservoir.
12. Loosen the nut below the nipple with a 10mm closed-end (box) wrench (a 12 point or 6 point one should work). Use a 12mm wrench to hold the body of the bleeder valve, or you may twist it off its mounting.
13. Coolant will rise from the nipple through the tube
14. Press power button twice w/o pressing the brake to enter IG-ON mode. The level of coolant in the reservoir will lower. Immediately but slowly refill with more coolant.
15. Coolant should flow in a dribble from the end of the tubing into the funnel.
16. Squeeze the hose going into the inverter, below the inverter between the inverter and the front of the car, to get more air out of the system. You can squeeze the plastic tubing to increase the velocity of the air bubbles.
17. Once you've drained out all the air and fluid stops passing through the hose, gently just tighten the nut. Do not over tighten.
18. Look at fluid in the reservoir through the opening. You should see turbulent, swirling movement of the fluid. Put back the top of the reservoir.
19. Disconnect the plastic tubing from the nipple after tightening the nut. Replace the plastic cap.
20. Put back the radiator cover. Slide it over the hood release handle first.
21. Put back fasteners for radiator cover.

Let me know if you spot any mistakes here or there's any other threads or guides that should be added.

Thanks,
Owen

 

Thank you! Seemed like the least I could do.