2009 Vibe AWD A/C on causing warning lights?

[eriksenz]

We have a 2009 Pontiac Vibe AWD and the Check Engine, Traction Control, AWD, and VSC off (flashing) lights all come on after the Air Conditioning has been used for 20+ minutes and after heavy rains. If you turn the AC off, 2 startups later lights go off - or after a couple drives after heavy rain (if it's no longer raining). When the lights are on the car runs totally normal.

When this first happened we got the codes scanned at Advanced Autoparts and it ran as P0138 (Crank position sensor high voltage bank 1 sensor 2), P0335 (crank position sensor), and P0607 (Control module awd light on). But shortly after the lights went out and by the time we got to the mechanic there were no codes to scan. A few weeks later the lights were back on and when our mechanic ran it he only got the code for an engine control module error.

The fact that it's so linked to moisture has me second guessing an issue with the ECM... If anyone has any thoughts or suggestions on how to fix this I would really appreciate it!

2009 Pontiac Vibe AWD, 155k miles, located in New England area.