Electronic Control Module (ECM)
The ECM monitors and processes data from various sensors, and sends output signals to fuel and ignition system components. ECM diagnoses out-of-range signals. A faulty signal causes ECM to turn on CHECK ENGINE light. Faulty signal records are stored in ECM memory and can be retrieved as fault codes.
The ECM is similar to those in various other General Motors vehicles. To adapt it to specific applications, each ECM is fitted with a replaceable Memory Calibration (MEM-CAL) chip. Manufacturers may update MEM-CAL chips to repair driveability problems.
NOTE:
Components are grouped into 2 categories. The first category covers INPUT DEVICES, which control or produce signals monitored by the ECM. The second category covers OUTPUT SIGNALS, which are components controlled by the ECM.