Saw this article at
https://www.tirebusiness.com/article/20 ... ibe-owners. I haven't had the problem or assessed the reasonableness of the remedy, but I thought I'd post it up in case it might help someone here someday
Clogged evaporator drain may be problem for Pontiac Vibe owners
The owner of a 2003-10 Pontiac Vibe may come into your store complaining that the check engine light and/or VSC lamp comes on intermittently. With a little detective work you may find trouble code P0607 and/or P0138 logged in the PCM. According to General Motors Co., the problem usually surfaces in high ambient temperatures with the air conditioning system on and is most likely due to water entering the pre-cat O2 sensor's electrical connector. A clogged evaporator drain is the true villain. Drying the connector and clearing the drain should eliminate the trouble.
Begin the fix by removing the small side panel cover just to the right of the accelerator pedal. Now pull the carpeting back to access the O2 sensor connector. Separate the connector halves, dry the terminals with compressed air, fill both connector halves with silicone grease, then reconnect the two halves. To complete this portion of the repair, pull the carpeting back into position and reinstall the side panel cover.
Now turn your attention to the evaporator drain. Start by putting the vehicle on a lift. Locate the drain hose, then use a coat hanger or compressed air to clear the blockage. To complete the fix, lower the vehicle, start the engine, turn the A/C on and make sure condensation flows freely from the drain hose.