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.

Crankshaft Position (CKP) sensor sends pulses to Powertrain Control Module (PCM) when the reluctor teeth rotate past the sensor. PCM uses the pulses to synchronize ignition and fuel injection operation. The PCM also measure interval between each pulse to determine if an excess change in crankshaft speed has occurred. A misfire causes an unwanted change in crankshaft speed. A certain amount of crankshaft acceleration or deceleration is expected between each firing stroke. If crankshaft speed changes are more than an expected amount, PCM will interpret this as a misfire. If 2 percent or more of all cylinder firing events are misfires, emission levels may exceed mandated standards. PCM monitors blocks of 200 engine revolutions and counts the number of misfires in each block.