I have had a recurring problem for at least a couple of months now.

I am driving along merrily, the red triangle pops up randomly, the car goes into limp mode, electric motor working only, top speed of 10 mi/h. If I disconnect the aux battery for a few minutes, the car drives again, but not for very long. The longer I wait, the longer the car will drive before the same thing happens again.

Thinking about it, this has only happened when I started the car after a few days in the garage, parked for a while, then went on my way again. I have driven 50 miles with no problems without parking. Today, I have driven less than 12 miles, but parked for 2 hours after 6 miles, and had to limp home for the last half mile.

Does anybody have any ideas? I initially assumed the P2122 and the P2138 codes were because of the limp mode, but maybe not?

PS.: I have posted this on Priuschat too.