The 2.2L engine doesnt have a camshaft position(cmp) sensor.
CIRCUIT DESCRIPTION This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition control module (ICM) detects when #1 or #3 cylinder has fired on its compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output, the higher output is always at the event cylinder. The ICM sends a CMP signal to the powertrain control module (PCM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the PCM can accurately time the operation of the fuel injectors. If the PCM receives an intermittent CMP signal from the ICM, the CMP Resync Counter on the scan tool will increment. When the PCM cannot use the information from the CMP signal, DTC P0340 will set. CONDITIONS FOR RUNNING THE DTC The engine is running.CONDITIONS FOR SETTING THE DTC The PCM does not detect any change in the CMP signal for 35 crankshaft revolutions (70 combustion events) when manifold absolute pressure (map) is at 55 kPa or greater.ACTION TAKEN WHEN THE DTC SETS
CONDITIONS FOR CLEARING THE DTC
If this DTC is determined to be intermittent, refer to Intermittent Conditions
Correct, there is no cmp sensor. what I provided above is straight from gm service manual for your vehicle. As it states, the cmp signal is sent to the on-board computer from the ICM(ignition control module). The ICM receives this signal from sensing circuitry built into the #1 and #3 ignition coils.
What you have to understand is that the code readers and definitions that Autozone uses are generic, which mean that they are generally applicable for all makes and models. But, they are not manufacturer specific for your particular make, model, and engine size.
The code definition for DTC P0340 for your specific vehicle and engine size is the one I provided.
Possible causes include:
The most accurate way to diagnose this problem is with a diagnsotic scanner with testing and live data capability in order to know which of the above is failing. If you decide not to have this done to determine problem, then you are left with replacing each part one at a time until problem is fixed, which will likely cost you several times as much as paying 1 hr labor for the diagnostics to be done. Then you can decide whether this is something you can repair yourself or not.