Drivers of 2012 Chevy Colorado or GMC Canyon pickup trucks with inline engines may complain of a screech or howl from the drive belt along with a rough idle.
In some cases, the Check Engine light may also be on, with trouble code(s) P0106, P0014 and/or P0017 stored in the PCM.
Two possible causes for the trouble are a defective camshaft actuator solenoid or excessive crankshaft end play due to a worn thrust bearing, reports GM.
Begin your investigation by removing the camshaft actuator solenoid. As noted in the illustration, the solenoid has three grooves with oil feed holes. Groove No. 1 supplies advance pressure to the cam actuator; groove No. 2 supplies pressurized oil from the oil pump while groove No. 3 supplies retard pressure to the actuator.
What's not obvious are the three fine screens in the grooves that prevent small dirt particles from entering the cam actuator. If any of the screens are clogged or missing, replace the solenoid, change the oil and filter, then start the engine and see if the symptoms are still present.
If the cam actuator solenoid looks good, check the crankshaft end play. Normal end play should be .004-.015 inch. If it's off by .001 inch or so, it's not a big deal. Just replace the cam actuator solenoid, change the oil and filter and you should be done with the fix. If the crankshaft end play is way out of spec however, say .050-inch, the thrust bearing is worn. Your only two options are to replace the complete short block or install a new crankshaft and bearings.
Note that GM recommends replacing the short block because it will be tough getting out all the thrust bearing material left behind in the engine, which will either damage the new crankshaft and bearings or cause the trouble codes to reset due to the tight tolerances in the cam actuator.