Circuit Description

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

The Crankshaft Position (CKP) sensor is actually 2 sensors within a single housing. There are separate power, ground (reference low) and signal circuits connecting both sensors to the Powertrain Control Module (PCM). The PCM supplies 12 volts to the CKP sensor. The PCM can use 3 different modes of decoding crankshaft position. During normal operation, the PCM performs an angle based calculation using both signals to determine crankshaft position. The dual sensor allows the engine to run even if one signal is lost. If either signal is lost, the PCM switches to a time based method of calculating crankshaft position. If the system is operating in Time A mode, the PCM is using only the signal from sensor A. Time B indicates that the sensor B signal is being used. If the lost signal is restored, the PCM will continue to operate in Time A or B mode for the remainder of the current key cycle. The PCM will automatically revert back to the Angle mode on the next start-up if the fault is not present.