My wife has a 2011 HHR LT, don't recall the miles but I think it's over 130k.
This year its been acting up in that the speedometer will act erratic even at a stop, sometimes when moving from a stop, it'll stall and die and the only code is from an anti theft sensor. I've replaced the sensors on top of the motor and it was OK for a few days but then was right back at it. Just a few months ago she took it in for the ignition recall thinking that was the problem and it was OK for a week but nothing has fixed it. Is this a common issue or does a legit mechanic need to get hands on it? I've even tried cleaning the throttle body to no affect.

As a side note, we know there's a transmission leak from the previous owner who boogered the pan install but would that make a water trickling sound on acceleration if the fluid is low?
If this post is dupe, I apologize, I simply don't know what search terms I'd use to find pointers in this forum.

 

It could be the speed module on the transmission isn’t getting fluid. Water gurgling is usually the coolant in low and air got into the system.

 

That for the response. My immediate thoughts are adding/replacing Trans fluid and checking the coolant, add as needed, correct?

 

If the coolant is low in under the rad cap, burp the coolant

https://www.chevyhhr.net/forums/how-...-system-60614/


To check transmission fluid, you remove the 11mm plug on the passenger side , it’s full when fluid drips out, check it warm and on a level surface. Or if the pan gasket is leaking anyway

https://www.chevyhhr.net/forums/how-...-change-58325/

 

Have you checked the battery? The alternator? The AC compressor?
Any CheckEngineLight you forgot to mention? Any strange sounds? Any work done just before this started?

 

the speedometer receives information from the transmission - you need to look for a goblin there!

Well, check the electrical contacts to clear your conscience