Jumper cables hooked backwards!

odd I thought it was usually the donor car that gets zapped with cables that are backwards. I would start in checking all the fuses in the fuse box and pulling relay's to check from the relay box. Why so few miles on the car I mean that car is 7 years old and hasn't even been driven 2000 miles a year.

 

Generally this is a serious and expensive error. You may be lucky, but the odds are not good. Start by looking at the main fuse, then work your way out from there. Reversed polarity will often fry one or more of the ECUs. Pretty much the only thing you can do is replace them if that happens.

Tom

 

Do you have any manuals for the Prius?

Do you have a scanner to read the ECU codes?

Bob Wilson

 

Although I still consider myself to be a Newbie, -- just got my 5K mi. service --
and am electricity challenged, from what I've read here on PriusChat and
numerous other forums, you are in one of the few "Avoid This At All Costs"
situations.

I have read that you can reset the CPU's by entering then exiting the READY
condition three times in quick succession. If it works, this might get your MFD,
etc. back on line. Then of course a trip to Tyota service to have them check
the error codes. (If you have access to a ScanGauge, you could get a
preliminary readout.)

With any luck, Hobbit, Patrick Wong, Bob Wilson, or one of the other e-smart
posters will log in with heavy duty advice.

 

I suggest that you carefully inspect all fuses to see if you can find any that have blown. If so replace them.

Note that you have two fuse boxes on either side of the engine compartment and a fuse box on the side of the dashboard that you can see when the driver's door is open. I would not worry about the relays.

Then disconnect the 12V battery for a few minutes so that any trouble codes stored in the ECUs will be cleared. Then reconnect a well-charged (or new) 12V battery, and see if the car will start.

If not, then I suggest that you have your car towed to a Toyota dealer so that the DTC can be retrieved. The DC to DC converter within the inverter is a likely item to have been damaged with a botched jump-start, since it lacks protection against this eventuality.

Sometimes the main fuse will blow. However it appears that this did not happen with your car since some circuits still have power.

The consequences to Prius of an incorrectly-performed jump start are quite high, so I recommend that all owners learn how to do this and not allow a well-meaning but careless third party to render this service. Better yet, keep the 12V auxiliary battery in top condition at all times so that a jump start is unneeded.

 

The consequences to Prius of an incorrectly-performed jump start are quite high, so I recommend that all owners learn how to do this and not allow a well-meaning but careless third party to render this service.

Repeated with bold, for emphasis. Because Toyota has not included polarity protection for the Prius computers, we must manage this ourselves.

 

I would think you could go to a junk yard and get what is fried at a fair price. But reversing the cables is very bad. You should always be the one in control of the cable and have the other person double check you before the last connection is made. Red-12v+ black =12v-

 

If you can get the Prius to READY, measure the voltage across the 12V auxiliary battery. It should be ~13.8V if the DC to DC converter is working correctly.

If the voltage is lower, that is evidence that the DC to DC converter is not working. DTC P3125 will also be logged if that system has failed.

 

OUCH!! Holy sparks and battery acid spray, Batman!
Yes, Boy Wonder there are still people who shouldn't play with electricity!

In the days when generators where still found in cars, folks with alternators were told not to jump start their cars from a generator. Something about the generator not be regulated enough to prevent frying the stator in the alternator.

There are a number of things you could have fried having jump started your car the wrong way. Does the Prius have a fuse-able link? This is normally a safety feature that prevents excessive voltage from traveling the wrong way. Starter relay, again I'm not sure if the Pruis has one.
If you needed a jump start in the first place is the little battery bad, is the alternator working properly?
I agree with the advice already given, check the little battery, replace it if need be. Definitely leave the little battery disconnected for a few hours, then hook it back up and try to start your car. Checking the fuse's is also a good idea, could help to find what circuit you might have problems with.
Check as much as you can or have some one who knows cars check as much as the can for you. Taking this problem to the dealer is going to cost a few big dollars, sounds like a flat rate job....

 

Most likely the main fuse but if you replace it & it blows I see Gen1 Inverters on eBay all the time from $200 to 500. Also you could actually fix the problem with a fuse replacement and not know it if you have a bad aux battery in the mix. Don't jump that battery again replace it & the fuse. But Inverter replacement is easy compared to the front clip. You sound pretty courageous I mean handy. I'd take a shot at that before I'd go to the dealer. They will hose you. Also the $150 investment on a Scan Gauge sold here is money well spent as it can read other cars codes too.

 

No starter relay because theres no starter.

 

This is why I got a 700 amp jump-start box from Canadian Tire. I'm far more likely to pay attention to polarity than a well-meaning but clueless helper, I have access to the box anytime, and it claims to have polarity reversal protection built in

As more Prius cars enter the fleet, to replace less fuel efficient vehicles, we can expect more of these reports. Toyota should have engineered polarity-reversal protection into the car

 

Yes. The individual ECUs probably have diode protection in their power circuits. I have not seen a requirement to replace every ECU in the Prius after this incident occurs.

However if the DC to DC converter had diode protection, that would require big diodes that can pass 100A of current. A silicon diode has a ~0.7V voltage drop, which would result in a large power loss when the current flow is high.

 

What's the maximum current that ever normally flows from the converter to the 12V battery?

But the only point that really needs protecting is the 12V+ jump point under the hood. A 50V PIV diode there, cathode connected to the original jump point, anode normally unconnected and serving as the new jump point, should protect everything (assuming that one never bypasses it by getting direct access to the battery) and not introduce any diode drops during normal operation. I'm guessing that a diode rated at 50A would be sufficient.

 

As was stated earler, no starter relay. Hmmmmm....have to find out how they spin the ICE to start it. Maybe power from the MGs.

Alternator? Hmmmmm..... again. Does the Prius have one? I thought the MGs generated all of the electric current.

Still learning stuff, Bob

 

Since the fuse between the battery and the DC bus is 100A or 120A, I assume that Toyota expects the "normal" current will be some level below that.

Note that the OP has a 2001 which does not have the jump terminal under the hood. Hence this trouble was caused by hooking up the jump cables incorrectly to the 12V auxiliary battery in the trunk.

I agree that a diode could protect the 2G dedicated jump terminal and not cause any problem with normal operation. However if the 2G battery were to be jumped directly at the terminals, the same problem could occur unless a diode was inline between the battery and the 12V bus, which would cause the voltage drop that I previously described.

 

MG1 is used as the starter. MG1 and MG2 do the job of the alternator.

Tom