Computers and Control Systems

Diagnostic Reference Values:

1. Diagnostic reference values are based on engine warmed to normal operating temperature.
2. Key On Engine Off (KOEO) and hot idle values are recorded with the vehicle in NEUTRAL (M/T) or PARK (A/T).
3. Before proceeding with timing checks, the monitor must be calibrated to base timing. Base timing equals 10 degrees.
4. Use third gear for 30 mph values and fourth gear for 55 mph values for vehicles equipped with a manual transmission. Use DRIVE for the 55 mph values for vehicles equipped with an automatic transmission.
5. Reference values shown in the charts may differ between vehicles due to component tolerances, driving conditions, weather, etc. These values were recorded at approximately 600 feet above sea level and ambient temperatures ranging from 50 to 70 degrees Fahrenheit. Some EEC-IV devices are temperature dependent and their values may vary greatly. Other values are calibration dependent and may also vary.