Battery jump fried ECU

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A friend of mine has a Prius. She had it jumped a week ago by AAA, after they jumped it, it drove but it went into limp mode.

She took it to the dealer and they determined the ECU was bad, including a knock sensor and a few other small things. Car drives fine now but AAA is telling her they didn't do anything wrong because their charge packs have reverse polarity protection.

Isn't the reverse polarity protection on the battery pack side only meant to protect the battery pack and not the car?
 
Doesn't sound like a reverse polarity issue. More like spikes on the line from the jump, maybe. Which the electronics should have been fine with, they get designed for that sort of noise.

IMO it's something else. Like a bad ground. Or the battery is loose, or it's just plain bad (why did it need a jump in the first place?).

Did she watch them do the jump? At any time did the guy say "oh crap!" and move the wires around? If all he did was hook it up and then it started, then the wires weren't swapped.
 
Originally Posted by supton
Doesn't sound like a reverse polarity issue. More like spikes on the line from the jump, maybe. Which the electronics should have been fine with, they get designed for that sort of noise.

IMO it's something else. Like a bad ground. Or the battery is loose, or it's just plain bad (why did it need a jump in the first place?).

Did she watch them do the jump? At any time did the guy say "oh crap!" and move the wires around? If all he did was hook it up and then it started, then the wires weren't swapped.


Not sure about that, all she told me was that they left the hood open during a rain storm and that after they jumped it the car was in limp mode and the dealer determined that there's no way a ECU can get damaged unless it was jumped wrong.

She's just wants to know if AAA's statement is any true. They said that it's impossible for their battery packs to cause any damage because if has reverse polarity protection
 
The jump only gets the vehicle started, does not charge up the battery. I could see the car being in "limp mode" with the battery not charged but would not expect it to damage the ECU.

Some jump packs can do 12 or 24V I wonder if 24V was used?

I think there is more to the story.
 
That's why we regrettably have to decline to jump anyone's battery. Too many bad things can happen, modern cars have a litany of small things that can be damaged. Fraught with peril.

Even in the rare case we jump one of our own vehicles I always make sure that I only run the jump vehicle for a few minutes, then shut it down before attempting to start the other one.
 
Originally Posted by dogememe
They left the hood open during a rain storm? How is that AAA's fault LOL.

Not sure the hood matters, you can pressure wash an engine (to some level) and it's fine. The connectors are waterproof. Many engines get wet from water going through the radiator in a rainstorm.
 
FWIW-- Had a dead battery on a '13 Kia Rio. Girlfriend had AAA so called someone to start it. They put + to - and the battery-jumper quickly drove off. Local dealer to which it was towed was able to get things going but the entire wire harness failed almost a year later--thousands of dollars. Kia refused to fix under warranty blaming it on the bad jump. I had been emailing the tow company about it for months, had a large file of unanswered correspondence, and AAA reimbursed me and took it out of the tow company's hide.

They informed me that the tow company had bought a web page/email combo but had never checked their email. There were quite a few "you wrecked my car" messages in there from all sorts of incidents. There was also a customer feedback panel on their web page full of vitriol. Again, never checked by the owner.
crazy.gif
 
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Wait, it drives fine now AFTER the dealer fixed it? Or it just went back to normal. Prius' will often go into limp mode due to voltage fluctuations in the 12v system. Unless they jumped it backwards I doubt they hurt anything.
 
Originally Posted by dogememe
They left the hood open during a rain storm? How is that AAA's fault LOL.


AAA left it open trying to find the 12v battery. So yeah it's their fault lol
 
Originally Posted by supton
Originally Posted by dogememe
They left the hood open during a rain storm? How is that AAA's fault LOL.

Not sure the hood matters, you can pressure wash an engine (to some level) and it's fine. The connectors are waterproof. Many engines get wet from water going through the radiator in a rainstorm.


That's what I was saying. I've driven my car thru ponds with no electrical issues. It's just what I've been told by the owner, I doubt anything was damaged from the water but there is no way a ECU just goes bad from a jump, unless the charging cable was mixed up. But they're saying the ECU just happened to fry itself and that It's not AAAs fault because their battery packs have reverse polarity protection. Even if they hooked up the terminals right they could have over powered the system...still their fault IMO. It's like if they towed an AWD vehicle with back wheels on the ground
 
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I'd take it to another dealer and get a second opinion. Too easy for the first shop to make a buck. There is probably a procedure to reset the limp mode. There is no way to collect from AAA. Check the fine print. They have it all covered.
 
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The Prius and maybe other hybrids have a different way to jump start a vehicle:

"Detailed Steps for Jump Starting a Hybrid Vehicle From Toyota



Step 1 and Step 2: Find the Jump Start Terminal Under the Fuse Box

Open the hood and locate the fuse block cover. It is a vaguely rectangular piece of plastic with a flat surface. Next, open up the lid covering the exclusively-used terminals used for jumpstarting a dead battery.
Image of the Prius Manual: Step 1 is to unclip the fuse box cover, which houses terminals specifically for jump starting the battery. Step 2 is to lift the cover and expose the terminals so you can safely jump your Prius.

Step 3: Connect the Jumper Cables
1.Clip the positive lead of the jumper cables to the jump starting terminal on your Toyota Prius.
2.Connect the other positive lead to the positive battery terminal of the assisting vehicle or to the positive terminal of the Quick-kick unit that will be providing auxiliary power.
3.Attach the negative lead to the negative terminal of the assisting vehicle's battery or Quick-kick unit.
4.Affix the remaining negative lead to a solid, unpainted piece of metal away from any moving parts and the exclusive jump starting terminal. Please use the below center photo as reference.

Image of the Prius Manual: Step 1 is to unclip the fuse box cover, which houses terminals specifically for jump starting the battery. Step 2 is to lift the cover and expose the terminals so you can safely jump your Prius.


Jump Starting a Prius, Step 3 as shown in the vehicle manual, detailing the battery connection steps: Connecting the positive leads, first connecting to the receiving car, then to the supporting car's positive terminals. Next, connect the negative lead to the assisting car, and then the other end to the receiving car on an unpainted piece of the frame.

Step 4: Jump Start the Hybrid
1.Start the engine of the assisting vehicle or turn on the Quick-kick unit. If you are using a second vehicle, gently start to rev the engine slightly and maintain that level for about five minutes to give the dead battery enough electricity to restart the Toyota Prius.
2.While the assisting vehicle is maintaining engine speed, start to spool up the hybrid system of the Prius by turning the power switch to the "ON" position.
3.Someone should be watching the indicator panel of the Toyota Prius for the "Ready" light to come on.

Step 5: Remove the Cables Properly
1.When the hybrid system has started, remove the cables in the opposite order you attached them. Follow this: 1.Negative lead attached to a metal piece.
2.Negative lead on the assisting vehicle or Quick-kick device.
3.Positive lead on the assisting vehicle or Quick-kick.
4.Positive lead on the jump starting terminal of the Prius.

2.Close the cover exclusive jump starting terminal.
3.Reinstall the fusebox cover by first hooking the cover onto the two rear tabs."


AAA most likely unknowingly of this separate jump start terminal just connected the jumper cables to the battery.
 
^^^^^ That sounds like the procedure for jump starting any vehicle with a battery outside of the hood compartment. It's to avoid the voltage drop from the remote battery location under the high current load of the starter motor to make it easier to jump start.

Automotive electronics exist in a harsh environment and are not fragile. It's hard to see how this is on the jump box.

My gut feeling is that a shop is trying to put an easy, expensive, and unneeded repair, off on someone else's money.
 
Originally Posted by SteveSRT8
That's why we regrettably have to decline to jump anyone's battery. Too many bad things can happen, modern cars have a litany of small things that can be damaged. Fraught with peril.

Even in the rare case we jump one of our own vehicles I always make sure that I only run the jump vehicle for a few minutes, then shut it down before attempting to start the other one.


Originally Posted by double vanos
Im with Steve SRT8: I jump start cars no more. The last thing I want is to jump someone's car and find out I damaged MY car!

This is more of a reason for everybody to do Battery Preventive Maintenance.
1) Posts - Keep clean
2) Acid/water level - Check
3) Voltage - Check
4) Alternator voltage output - Check
5) Battery Tender/Minder if it not going to be driven or during severe weather
6) Older battery (after so many years) - Replace
 
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Batteries still can need a jump. I went on vacation once, flew away for a week--and left the kids DVD player on in the backseat. Oops. One jump and all was fine.

Couple years ago my truck decided to have a dead battery. No door was left open, no idea why it was flat. Gave a jump and all has been fine since. Been about 2 years, and that is the original battery--it's now pushing a ridiculous 9 years of life!

I usually just replace the battery after it fails--when it gives grief, get enough jumps to get to Walmart, replace in parking lot. I've never done more than that in twenty years. Oh I did proactively replace wife's battery around the 5 year mark, when it started cranking slow in bitter cold temps.
 
Modern vehicles require a completely different method of jumpstarting. The first thing anyone needing a jump is to read their owners manual. It has very specific instructions on jumping that specific vehicle. Gone are the days of connecting neg to neg and pos to pos. One step I see that people often ignore (other than not reading the owners manual) is to turn on the headlights on the vehicle with the weak or dead battery. The reason for this is that the headlamps will absorb any voltage spikes and protect the ECU
 
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