Arrgh...accidently shorted 12v battery briefly...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SFGiant-and-Plugin-Fan, Mar 20, 2011.

  1. SFGiant-and-Plugin-Fan

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    I touched the positive post of the rear battery to frame and recieved a brief spark. Now car starts, but after driving a mile got red triangle, (!) and VSC displays. Also, MFD is blank. Is there a fuse I may have blown?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Was the car IG-OFF when you shorted the 12V battery's positive terminal? If yes then I do not think you have to worry about a fuse being blown.

    If the car starts, that shows the 120A MAIN fuse located at the positive terminal fuse block is OK. However if the car was READY when you did this short, then you may have blown the 100A DC/DC fusible link which is located within the main relay/fuse box near the inverter. It is one of several links that live within a 5" long plastic box with a clear cover and white bottom. The fusible link assembly is not "user-serviceable".

    The non-functioning MFD may be an unrelated issue, if all other instrumentation is working.
     
  3. SFGiant-and-Plugin-Fan

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    Thanks. The car was off, The MFD has come back, but I continue to get the red triangle, exclamation point and VSC even after unplugging the battery for a few minutes. I talked with a long time Prius owner who thinks it is a low battery. I bought it used last year. It is a 2005 with 130,000 miles and I see no indication on the service record that the battery has ever been changed. Voltage reading is 12.4 standing. Is that low? Is it safe to drive? If so, I'll take a careful, low mph 12 mile drive to my Toyota mechanic tomorrow.
     
  4. SFGiant-and-Plugin-Fan

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    Everything is back to normal now. Disconnecting the battery did not work (codes came back), until I disconnected, then hooked up my wife's car battery to the Prius battery before trying to start. That seemed to convince the Prius computer that all was OK. I then was able to turn my car off and on without any warning displays. Also, my battery charge level does not seem to be far off average according to the postings I've read. I am 12.4v standing, 12.2v aux mode and 14v ready mode. This seems to be fairly normal. In doing the battery research I found another Prius feature I was not aware of, diagnostic mode. This car is a never ending stream of gizmos and gadgets. Never ceases to amaze me.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The voltage readings are OK. The 14V when READY shows you that the DC/DC converter is working (and that the DC/DC fusible link is OK.) Glad to hear that your car is back to normal now.

    For reference, a fully-charged 12V AGM battery in new condition will measure 12.9V out of the box. Discharged would be around 11.9V.
     
  6. SFGiant-and-Plugin-Fan

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    I made a sharp turn today and red triangle, (!) and VSC came back on. Got home and checked battery voltage directly with meter and readding was 12.7 standing but around 11.9 under load (aux mode with headlights). Diagnostic mode reading agrees, 11.9v.

    The car has 130,000 miles on it. I bought it used so I'm not sure if the battery was changed, but there is not record of it being changed on the car fax or the Toyota maintenance report. I made an appointment to have a new battery installed tomorrow. Meanwhile, I am trickle charging the current battery over night.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It's a good idea to replace the 12V battery to rule that out as a contributor to other issues. It apparently is 6 years old, and is probably marginal.

    I suggest that you check the inverter coolant reservoir for fluid turbulence when the Prius is READY. If you don't see this, the inverter coolant pump is not running. That would be a more likely reason for seeing the warning lights that you mentioned above.
     
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  8. seilerts

    seilerts Battery Curmudgeon

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    If you plan on serious modifications like the Enginer kit, you really need a scan tool that will read trouble codes. AutoEnginuity works well for Gen II, and is the next best thing to Techstream Lite, but is pricey at $400 or so. But it will show you everything that is happening in the system, and has bi-directional functionality, such as turning on the HV battery fan. I have the AutoLink CAN OBD reader as well as AutoEnginuity. The Autolink is an excellent value at around $60, and is surprisingly versatile. I loaned it to my stepfather recently, and he was able to read freeze frame data when the IMA light came on in his Civic hybrid.
     
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