I have a 2006 Chev. HHR with 104,000 miles and live in Windham, ME. The car runs great except when we drive through Baldwin, ME near the Saco River. We will be driving along and the door locks will unlock, the outside temperature reading will show — and the car shift into neutral for about 2 seconds. Then it goes back in gear, the temperature reads normal but the doors stay unlocked. If we lock the doors using the lock switch it will do the same thing two or three times then everything is fine. It has done this on three different days, different speeds and driving times. But it only has happened in the area of Baldwin close to the Saco River. We took it to our shop but they could not find anything wrong and could not get it to repeat the problem, They did not drive to Baldwin. No one we have spoken too has ever heard of this.
Can’t find anything about Baldwin that should do that. sorry.
My guess would be some kind of radio interference. Finding and eliminating it could be difficult.
This article about problems with the HHR key fob is pretty vague but might point you in some direction.
A call to the dealer might help.
You might try tuning your radio to am and see if you hear anything unusual when the problem occurs. Beyond that unless you have a friend with an RF spectrum analyzer you may never find the answer.
A very long shot, you could try filing a complaint with the FCC.