The checking procedure is applicable only to 2006 and earlier models, as 2007 and later models require special equipment and procedures. For 2010 and earlier 1.BL and 2012 and earlier 2.0L models, the Camshaft Position (CMP) sensor is located at the right rear corner of the cylinder head, with the electrical connector positioned above the injector for cylinder No. 1. In 2011 and later 1.8L models and all 2013 and later models (except for 1.4L models), two camshaft sensors are utilized, located on the top trans axle end of the valve cover. For 1.4L models, the intake camshaft sensor is found at the trans axle side of the cylinder head. The CMP sensor signals the PCM when the No. 1 cylinder is at Top Dead Center (TDC) on its compression stroke, allowing the PCM to fire the injectors in the correct sequence and timing. To check the sensor, back probe terminal 2 of the CMP sensor electrical connector using a suitable probe, then connect a voltmeter to measure the sensor output voltage at idle (800 rpm) and at 3000 rpm, which should fluctuate between zero and 5 volts at both speeds. If the CMP sensor does not function as expected, it should be replaced. For replacement, unplug the CMP sensor electrical connector, remove the sensor mounting bolt, and take out the CMP sensor(s) from the cylinder head or valve cover, with installation being the reverse of removal.