I have a Toyota Tacoma 2001 and my car won't start off the battery under the hood. The battery is brand new and has a full charge. It's been working perfectly for 3 months since I installed the new battery. Today it's like the car is not getting a connection to the battery. When I put the key in I get lights as normal, but when I try to turn the key everything shuts off and only 2 dash lights work. I would think it's just a starter issue, except when I hook up a portable jumper it starts up just fine. The battery voltage is at 12.8 and I was wondering if this seems like a solvable issue.

  • Did you check the alternator?
    – Shobin P
    Sep 22, 2015 at 11:37
  • 1
    Take the battery back and have it tested. It is possible it has become defective. Most auto parts stores can check your charging system too.
    – CharlieRB
    Sep 22, 2015 at 20:53
  • 1
    please don't call Tacoma a "car". I am deeply offended
    – amphibient
    Sep 22, 2015 at 21:29

2 Answers 2


Take the cables off of the battery and clean the terminals. You have a bad connection on one side or the other which is not allowing full power to get past. When you place the jumper onto the system, it is directly fed to the cables and allows the vehicle to start. Along the same lines, it could also be that one of the two battery connections is not completely tight ... same result as being dirty or having corrosion.

  • It is very important that the terminal clamps be reasonably tight. I think mostly the torque spec is around 45 in/lbs. I have had a situation a long time ago when the battery wasn't releasing charge precisely because the clamps were not tight enough. oh, the dielectric grease as well
    – amphibient
    Sep 22, 2015 at 21:42
  • @amphibient - If regular post batteries, I just use high pressure grease right out of the squeeze tube. Coat the entire surface of the terminal. I realize there aren't that many post batteries used in new cars ... Sep 22, 2015 at 22:55

The fact that battery has a good voltage would suggest that there's an open circuit in the battery. The battery is full of current it just can't come out. If your battery polls are clean and terminals are tight, then that's definitely the problem. The battery has to be changed

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