Two months ago,I got a CEL light,and the car started bucking under acceleration. A scan from Autozone showed a Code P0340,the Camshaft Position Sensor. I changed it out and the bucking has stopped,but the CEL light didn't go out. I had a shop clear the code but within a matter of a minute,it came back on. I went back to Autozone for a scan,and-yep,same code,same sensor. The car is due for an inspection by the end of October,and I can't have that CEL light on. So,what could be the cause of this?
Side note,strangely enough,the code appears twice on the sheet AZ gave me under the "Error Codes Read" box. Why would it appear twice?

 

P0340 is for the circuit, not necessarily the sensor. Did you replace the sensor on the intake or exhaust, they are both on the driver side. This code is for intake.

Is this the 2.2 or the 2.4?

 

There are 2 camshaft position sensors. P0340 indicates the intake. Note that the fault is in the circuit, not necessarily the sensor itself. There are 3 other codes that are for the sensor itself.

It appears twice because 1 is for the first time it popped up, but did not trigger the CEL and the second for when it did.

What year and engine?

 

RJ,the sensor just above the oil filter cap is the one I changed.

Donbrew,its a 2007 2.4

The only other sensor I saw in a diagram is the crankshaft position sensor,that's below. To me,there's a difference between a crankshaft and a camshaft. Then again,GM engineers have overthinked the plumbing numerous times...

 

Yes, of course there's a difference between a crankshaft and a camshaft. There is a sensor for each camshaft. There are codes for a bad sensor, this code unfortunately is not so specific. Now you check the rest of the circuit. I would start with a visual inspection of the wires for fraying or touching something hot; and of the connector, checking for loose or bent pins.

 

I’d also look for a dirty or loose ground wire

 

and rodents....

 

You were looking at a 2.2L diagram, in 2007 they did not have camshaft sensors., and the code means something different.

The sensor above the oil cap is the cam sensor. Did you replace it with a crank sensor?

This thread is about a 2006 2.2L, but in post #2 you will find a diagram that is pertinent to a 2.4L.
https://www.chevyhhr.net/forums/prob...-ecotec-59398/

 

That might be it,as I had to make 2 trips to the auto parts store. The first sensor they gave me had a receptacle for 3 wires,and the connector on my car has 2. I went back and showed them,and they looked up on their computer,then went in the back for a few minutes,and gave me the sensor with the correct receptacle for my connector. Maybe they goofed? And if the bucking went away that would mean the sensor is working,despite it throwing a code? And did GM,is all their bonehead wisdom,make 2 sensors look the same yet are different somehow?
And if that's the case,how do I tell the difference between a cam sensor and a crank sensor?

 

Camshaft position sensor

NEW Camshaft CAM SHAFT POSITION SENSOR CPS FITS 2006-2010 BUICK CHEVROLET PONTIA

Crank shaft position sensor