Monitored Circuits

The Powertrain Control Module (PCM) contains electronic circuit monitors that monitor fuel, vehicle emissions, engine and ignition system performance. Monitors use information from various sensor circuits for system monitoring. Monitors do not indicate a specific component failure, but do indicate an implied failure within a specified system, and that the problem must be diagnosed. If any monitor detects a problem affecting vehicle emissions, a Diagnostic Trouble Code (DTC) will be stored in PCM. The following monitors are used.

EGR Monitor
Engine Misfire Monitor
Fuel System Monitor
Oxygen Sensor Monitor
Oxygen Sensor Heater Monitor
Catalyst Monitor
EVAP System Leak Detection Monitor

The PCM will erase DTC once Malfunction Indicator Light (MIL) is turned off. Once MIL is turned off, PCM must pass diagnostic test for most recent DTC for 40 warm-up cycles on normal operation, or 80 warm-up cycles on engine misfire monitor or fuel system monitor.

NOTE: A warm-up cycle is defined as engine is started, an increase of 40°F in engine coolant temperature exists after engine is started and engine coolant temperature increases to at least 160°F.