Chasing Down A P3140

The safety interlock circuit is open. Usual culprit is the orange service safety plug that gets pulled out of the battery. Not only does it have to be put back, its handle has to be fully folded down and pushed lengthwise, to close the interlock switch.

 

I got a P3140, even with the service plug installed correctly. After a little fooling around, I figured out that the contacts on the microswitch that detects when the service plug is "in" got crudded up. Blowing into the switch fixed it.

You can take the switch off without pulling the whole traction battery out of the car, as long as you have a real short Phillips screwdriver. I used a 1/4" hex bit on its own as a tiny screwdriver.

The microswitch has a short 2-wire harness that goes into a connector on the outside of the traction battery. If that harness or connector got beat up, you might also get P3140. You don't have to take the battery out to see this; just open the trunk, take off the fuzzy lining if needed, and look.

You can also get P3140 if you have been fooling around with where the MG1 and MG2 wires bolt to the inverter, under the hood. If all you did was a traction battery swap, though, you wouldn't have touched those connections at all.