In order to meet Federal Exhaust Emission and Fuel Economy regulations, today's vehicles are equipped with highly sophisticated electronic engine control systems. These systems do not require periodic adjustments. The only services required on a scheduled basis are spark plug and filter replacement. Tune-ups, as we knew them, are no longer necessary.

Engine Control Computer

The computer receives information from a network of sensors and switches that convert engine operating conditions into electrical signals. Based on the information and instructions stored in the computer program, commands are then sent to three primary systems:

• Ignition System
• Fuel System
• Emission Control System

The sensors that monitor one or more of these systems include

• Mass Airflow Sensor
• Throttle Position Sensor
• Manifold Absolute Pressure Sensor
• Coolant Temperature Sensor
• Exhaust Oxygen Sensor
• Crankshaft Position Sensor
• Camshaft Position Sensor

Engine Diagram

1. Mass Airflow Sensor
2. Throttle Position Sensor
3. Manifold Absolute Pressure Sensor
4. Coolant Temperature Sensor
5. Exhaust Oxygen Sensor
6. Crankshaft Position Sensor
7. Camshaft Position Sensor