Electronic Control Module (ECM)

The ECM maintains proper spark and fuel injection timing for all driving conditions. The ECM monitors input signals from the following components to control Electronic Spark Timing (EST):

• C(3)I Ignition Module
• Coolant Temperature Sensor (CTS)
• Manifold Air Temperature (MAT) Sensor
• Mass Airflow Sensor
• Park/Neutral Switch
• ESC Module
• Throttle Position Sensor (TPS)
• Vehicle Speed Sensor (VSS)

Under 400 RPM, the ECM will start injector timing as soon as the C(3)I ignition module receives a cam signal, synchronizes spark timing, and controls fuel injection timing.

The C(3)I ignition module controls spark timing during this period. Over 400 RPM, the ECM controls EST. It also changes fuel injection timing to a sequential mode (provided a camshaft signal is received).