Engine Control Module (ECM)Modes of Operation

The engine control module (ECM) is responsible for maintaining proper spark and fuel injection timing for all driving conditions. The electronic spark timing (EST) is the method the ECM uses to control spark advance. The ignition module is integrated inside the ECM, and the primary coil ON/OFF is directly controlled by the ECM. To provide optimum driveability and emissions, the ECM monitors input signals from the following components in calculating ignition spark timing:

• The crankshaft position (CKP) sensor
• The throttle position (TP) sensor
• The engine coolant temperature (ECT) sensor
• The manifold absolute pressure (MAP) sensor
• The intake air temperature (IAT) sensor
• The vehicle speed sensor (VSS)
• The knock sensor (KS)