Powertrain Control Module: Notes

Powertrain Control Module (PCM) is located under the air cleaner assembly. For illustration of PCM location, see COMPONENT LOCATIONS in SELF-DIAGNOSTICS - 4.6L DEVILLE & SEVILLE article.

The powertrain has electronic controls to reduce exhaust emissions while maintaining excellent driveability and fuel economy. The PCM is the control center of this system. The PCM monitors numerous engine and vehicle functions. The PCM constantly looks at the information from various sensors and other inputs, and controls the systems that affect vehicle performance and emissions. The PCM also performs the diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the Malfunction Indicator Light (MIL). When the PCM detects a malfunction, the PCM stores a Diagnostic Trouble Code (DTC). The problem area is identified by the particular DTC that is set. The PCM supplies a buffered voltage to various sensors and switches. Review the components and wiring diagrams to determine which systems are controlled by the PCM.

The following are some of the functions that the PCM controls:

• The engine fueling.
• The Ignition Control (IC).
• The Knock Sensor (KS) system.
• The Evaporative (EVAP) emissions system.
• The Secondary Air Injection (AIR) system (if equipped).
• The Exhaust Gas Recirculation (EGR) system.
• The generator.
• The A/C clutch control.
• The cooling fan control