odd surging at idle

[20LTZ13]

ok so for awhile now my sonic surges when the a/c is on when the vehicle is idling. i took it into the dealer and they replaced multiple clutches in the transmission advising there is a tsb related to the problem. the issue is still present with no real change after the repairs. I took the vehicle back in and they tried resetting my shift parameters and cleaned the throttle body and still the problem is ongoing. has anyone else experienced this before?

2013 ltz 1.4t

 

[bdub]

my 2015 1.4t auto does this sitting in park with the a/c on it will randomly rev a bit and then die off if that's what you are referring to.

 

[20LTZ13]

yes, mine does that as well. but the surging is violent enough that people in the car behind me can see the car lunging and passengers in the car can feel it and always ask "umm what the heck was that"

 

[20LTZ13]

and also it mostly does it when the trans is in drive. its way less noticeable when its in park

 

[Chevrolet Customer Care]

ok so for awhile now my sonic surges when the a/c is on when the vehicle is idling. i took it into the dealer and they replaced multiple clutches in the transmission advising there is a tsb related to the problem. the issue is still present with no real change after the repairs. I took the vehicle back in and they tried resetting my shift parameters and cleaned the throttle body and still the problem is ongoing. has anyone else experienced this before?

2013 ltz 1.4t

Hello 20LTZ13,

We understand how frustrating reoccurring vehicle issues can be and we'd like to apologize for the inconvenience you have experienced regarding the multiple repairs on your Chevrolet Sonic. Please send your VIN, mileage, contact information, and involved dealership in a private message. I'd be more than happy to investigate this matter and work toward a possible solution.

I look forward to your message.

Jasmine F
Chevrolet Customer Care

 

[20LTZ13]

pm sent, thanks for the help!

 

[2014 Blue RS]

Same here. Most noticeable when the car is cold and sitting a stop light in gear. Solution for me is to put it in neutral until the light turns green. Other people have noticed it (which I hate).

When the engine is warmed up it happens but it's very subtle and I probably only notice it because I've already been made aware that it does this when it's cold. No one else in the car would notice.

 

[20LTZ13]

Same here. Most noticeable when the car is cold and sitting a stop light in gear. Solution for me is to put it in neutral until the light turns green. Other people have noticed it (which I hate).

When the engine is warmed up it happens but it's very subtle and I probably only notice it because I've already been made aware that it does this when it's cold. No one else in the car would notice.

that's exactly the way mine is. It doesn't seem to surge nearly as bad once it gets warmed up.

 

[StickyToes]

Yup, mine does it, too. Dealership technician can't replicate it, so they don't want to tear into it unless it acts up for them. I've kept a log of the incidents.

 

[JoeyWonderRS]

Mine makes a hissing sound, almost like microphone feedback at around 3k rpms when the ac is on. Anyone else get this? I have a '15 RS

 

[Hawkdsl]

To explain what is happening here, it's usually the IAC (Idle Control Valve), or some other like sensor. The ECM looks for drops in idle, and will compensate for it through the IAC or TPS. This keeps the engine from stalling when you did "power on demand" things like turn the steering wheel without moving, and running the A/C.

The simple solution would be an ECM calibration if a sensor is not defective. Changing out clutches made your dealer some warranty money I think.

Anyway, the bottom line is, it is a normal function of your car.

 

[20LTZ13]

To explain what is happening here, it's usually the IAC (Idle Control Valve), or some other like sensor. The ECM looks for drops in idle, and will compensate for it through the IAC or TPS. This keeps the engine from stalling when you did "power on demand" things like turn the steering wheel without moving, and running the A/C.

The simple solution would be an ECM calibration if a sensor is not defective. Changing out clutches made your dealer some warranty money I think.

Anyway, the bottom line is, it is a normal function of your car.

If its normal wouldn't every sonic do it? And the previous dealer replaced the clutches in reference to a tsb about the trans not shifting into neutral when coming to a stop like its designed to. Either way its annoying and embarrassing and honestly if its not corrected ill probably get rid of the car.

 

[drarkan]

Mine does it once in a while, i am curious if its related to the air intake filter not getting enough oxygen (ie needs to be changed) and causing a low idle which then makes the IAC to kick in.