My Prius is not well :( Check Hybrid System Msg

He's only getting the ECU.

This is exactly what we try to warn people about. When the 12v fails, it throws off codes. Dealer techs know nothing about diagnosis, they know how to read their code machines.

And like I also mentioned their "test" of it being ok, is a joke. Buy a multimeter...

Just go buy a battery, install it, and be happy! Otherwise you are going to get a whole bunch of new parts and be off the road for a while all for no reason.

 

Ah...I stand corrected. Still, glad its going to be covered by warranty.

 

Agreed with OBDII almost a domino effect. Looks like the real culprit may have gotten away. I have often thought about a plug in LCD volt meter for the accessory jack. Another reason to buy a ScanGuage II when I get the money.

 

The battery is usually about $180USD. And dealer techs are trained to read codes, look them up in the database, and find the "solution". Like you going to the doctor and the nurse technician operating on your because your symptoms match some rare tropical disease they found on webmd.com.

At least you are under warranty so it isn't costing you anything. But keep in mind, everytime they change a part, they bill Toyota corporate for the warranty work including their labour at the marked up rate. So they make a profit for replacing a part under warranty that doesn't need replacing.

 

If the HV ECU had failed the car would not move. I believe they're wasting your time and Toyota's money

Do you not know anyone with a multimeter? Because that would clear this up instantly if you get a reading of under 10V in the morning before starting the car.

 

Good to know you all are ASE master certified Toyota MDT techs. Perhaps you all should just diag your own cars. If you all refuse to believe dealer diag (granted everyone is not always right, techs are still human, we do make mistakes) why buy a car that at some point or another will require a dealer visit?

 

Yes, a good diagnosis is one of the reasons we go to dealers.
Can you tell me if TMC/TME do verify (later on) the "failed" components recovered under warranty?

 

As a tech I am sure you are aware of the sub-standard quality of many around you. I know the ones around here learn on the job. One of my acquaintances (sister's friend's brother) worked for a dealership and he never received any training. He was trained on the job with real customers cars and issues. It wasn't a big deal because after you hook up the scanner and it says "the problem is XYZ", you go and fix part XYZ. Doesn't work so well when the problem is the computer not powering up fully to correctly diagnose the situation and this is where most techs are lost.

I have no way of knowing if you are a good tech or not. I would hope you are. But judging from those I have seen and visited, I can diagnose my car better. When I ever need to go in and have a repair, I will tell them what I need and they will efficiently provide. Works out ok for me.

 

Could the component being replaced cause a 12V battery to go very low overnight?

 

With that test, I'll bet you a pint of Guinness, it's a failed 12V battery.

Might there be something else/also wrong? Sure. Will their diagnostic system work while there's a bad 12V battery installed? No. Has the slow bureaucratic Toyota revised all their diagnostic procedures to read "Step 1. Check 12V battery. If OK, goto Step 2..." No.

The G3 Prius batteries are CRAP. Not just small...crap. They spend their lives with a constant 13.8 V on them when it's running. No flaky alternator that drops out at idle when the A/C is on. No 600amp draw to start the motor. No 160F+ temperatures in the engine bay. 13.8V, nice steady DC all the time...and in the shade.

All they're called to do is boot a couple computers once in a while. And they still fail after about 18 months.

Problem is, there's no starter (to turn slow and warn you), so you don't know it's bad until it's totally shot, and can't even supply 10 amps to boot an ECU. Then when it does fail, the computers act all weird at bootup...bad for a car where the computers have full authority for everything.

Suggested test for everyone: Put it in ACC. Turn the A/C blower on high. turn on the headlights. Roll down both front windows simultaneously. If they both go down with the usual vigor and verve, you're ok. If not, you have a bad 12V battery and need to replace it ASAP.

 

I'm no "ASE master certified Toyota Tech", but I am an Electrical Engineer.

The HV ECU has filtering on it like every other ECU in any car. It is possible that one of the components (like a filter capacitor) was stressed and became a short. It can happen, and it actually just happened to me yesterday on a board I was working with (completely unrelated to Toyota or vehicles in general). When it happens the capacitor basically becomes a very low resistance resistor and pulls a BUNCH of current. If the input supply is current limited to a current rating less than the current needed to violently explode the capacitor (and therefore stop being a short and become an open) then it will just draw maximum current limited power.

So possible? Yes.

Probable? No.

A 2000hr/105C cap is common. At 35C you get about (2000 * (2^7))hours life, or just less than 30 years of constant 24/7 usage. In the automotive industry super long life caps are generally used and these numbers inflate even higher.

 

The original 12V battery was probably OK, but it was just not sized for the pattern of usage in your taxi. The two way radio and registration computer take enough power to run the battery down while the car is not in READY. The standard battery was never designed for such service.

Police cars typically have heavy duty alternators and batteries. When they retire police cars, they remove the police radios, patch up the bullet holes, paint over the police insignia, and auction them off, primarily for use as taxis. So your typical Ford Crown Vic taxi comes equiped with heavy duty alternator and 12V battery.

You can replace the 12V battery with another one of the same type, but the demands that you're placing on it will probably wear it out in another 18 months. A yellow top Optima battery will last longer in such service. Leaving the car in READY while you're waiting for an assignment will help with the battery, but use a small amount of extra petrol. If there is an issue with "no idle" rules, the Prius never idles. If the engine is running while the car is stopped, it is doing so to recharge the HV battery or to warm up. The "no idle" rules were written without an understanding of hybrids, and really shouldn't be applied to the Prius. The Prius already does an automatic "no idle" function whenever the car is stopped.

Take a look at http://priuschat.com/forums/gen-ii-...f-while-you-cant-drive-weeks.html#post1302460 for something you could do while the car is out of service.

 

Hokay, I'm both a shade tree mechanic and an Electrical Engineer. And getting to be a bit of an old codger by now.

This bit about, "The dealer tested the battery and it was OK", coupled with "With the car in standby, the windows sure take a long time to go up and down" really bothers me.

Back in the days before computers and hand-held whatchamcallits became standard, ye olde-tyme gas station mechanics had a little box, sometimes on a cart, sometimes not. Attach wires on the box to the battery terminals, rotate a couple of big selectors, and press a button: Needles would swing back and forth and the guy/girl could tell you if your battery was toast or not. Said box could also read battery voltages well enough to detect a bad cell. Other configurations would check if the alternator was up to snuff and so on. Every service station had one of these, and they weren't scams: You could walk in there with a perfectly good battery and alternator and end up with the regulator getting changed out.

My understanding with the battery tester was that they would dial in the cranking amps for the battery in question and verify that it could deliver that kind of current into a dummy load. (If it could, but the engine wasn't turning over easily, the next step was to look at the starter, etc.) So, let's say the Prius does have this crap battery and the one you have is going bad. A tester like this would have no problem figuring out that the battery capacity is shot. Heck, it's the same test as you and the windows going up and down, but with needles instead!

So, what is the dealership using to figure out if your battery is good or not? Diagnostic codes? If so, Wrong Answer. The right way to test a battery is under load.

The couple of times back when I was a poor starving sailor in the military and had Issues with my car's electrical system I would wander by a service station and ask for a test. The mechanic would go, "Sure, Mack!", haul out the cart, attach the wires, and push the button. I gave him $10 for his trouble (back in the 70's, that'd be around $60 nowadays) and went and replaced the battery elsewhere.

So, if you're going to replace the battery anyway, forget about all this and just do it. But if you're feeling curious, find an old time mechanic in town somewhere and see if the old box on the cart is in the back. Dial the cranking amps number down to the minimum and see what the battery has to say.

KBeck.

 

A DVM replaces that giant cart

 

Those testers are still around:

http://www.princessauto.com/worksho...300/60/30a-wheel-style-manual-starter/charger

 

If I'm not mistaken he means a giant manual non-auto ranging, non-digital multimeter, not just battery charger. I have a battery charger like that though, on wheels 300A start capability. Love it.

 

There is a possibility to add additional 12V bus supported by other 12V battery just to supply energy to your cab related stuff. The simple relay circuit will separate that bus when car is OFF or in ACC mode to save OEM battery.