Circuit Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
This diagnostic monitors the signal from the CKP sensor A. The crankshaft position (CKP) sensor is a magnetic generator type sensor, producing an alternating current signal. The CKP sensor signal increases in both frequency and amplitude as the engine speed increases. The CKP sensor sends this reference signal to the powertrain control module (PCM) to indicate the crankshaft speed and position. This reference signal is used by the PCM to calculate fuel injection pulse, establish top dead center (TDC) for ignition timing and where to start ignition coil and injection sequencing. There will be no spark or fuel delivery if there is no CKP sensor signal from either CKP sensor.