Circuit Description

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating catalytic converter damage is possible.

Conditions for setting this DTC are as follows:

• Misfire total is 12 counts or more.
• TP sensor angle has not changed more than 8 percent in one second.
• Engine run time is more than 15 seconds.
• Battery output 9-17 volts.
• Engine coolant temperature between 20°F and 254°F (-7°C and 123°C)
• Engine speed is 469-3400 RPM.