10 volts when key is "on" position

[Stunt'nSlide]

when my car is completley off the battery has 12 volts. when I put the key in the "on" position it's only at 10 volts. is that normal?

[KOME]

Your battery should be at 12.6 volts minimum to start with.

But not entirely sure on your question. It depends on what loads start to engage when you turn the switch.

Also, you didn't exactly say if it's causing a problem or not.

[Stunt'nSlide]

Your battery should be at 12.6 volts minimum to start with.

But not entirely sure on your question. It depends on what loads start to engage when you turn the switch.

Also, you didn't exactly say if it's causing a problem or not.

well my car has a hard time starting. but even before that my car had really bad idle and is throwing code 13, 21, and 32. I was checking the voltage on the ignition coil when the key was on and it only said 10.2 volts so I checked my battery and it said 10.2 volts also. but when I turn the key off my battery has 12.9 volts

[Superaison]

try another battery?? yours maybe going bad

[mr2thomas]

sounds like yours is bad. Basically with key on, you open a circuit but your battery is so weak it experiences voltage drop.