Monitored Circuits

2003 Chrysler 300M BaseSECTION Monitored Circuits

The 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 indicate an implied failure within a specified system, and that problem must be diagnosed. If any monitor detects a problem affecting vehicle emissions, a DTC will be stored in PCM memory. The following monitors are used.

  • Misfire Monitor
  • Fuel System Monitor
  • Oxygen Sensor Monitor
  • Oxygen Sensor Heater Monitor
  • Catalyst Monitor
  • EVAP System Leak Detection Pump Monitor

After 3 good trips, PCM will turn off the MIL. At that time, the PCM will automatically switch the trip counter to a warm-up cycle counter. The PCM will erase DTCs after 40 warm-up cycles (80 warm-up cycles for fuel system monitor and misfire monitor) if the recent malfunction does not reoccur in that time. For additional information on good trips and warm-up cycles, see TRIP INDICATORΒ .

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

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
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  • β€’ You are not confident in the next step or safety outcome.