Description & Operation

The center of the EEC-IV system is the Electronic Control Assembly (ECA). The ECA receives information from various sensors and switches. Based on information received, the ECA generates output signals to control engine and transmission operation. The EEC-IV system controls 3 major areas of engine operation: air/fuel mixture, ignition, and emission control. In addition, the system controls A/C compressor clutch operation, idle speed and transmission solenoids. The system has self-diagnostic capabilities.

The engine control system consists of the ECA, sensors, switches and solenoids. In order for the ECA to perform properly, it must be kept constantly informed of engine operating conditions. The engine sensors supply the ECA, via electrical signals, with specific information required to determine engine operating conditions. The ECA will then send out electrical signals to control air/fuel ratio, emission controls, idle speed, ignition timing and transmission solenoids.

Perform all possible test steps under TROUBLE SHOOTING in AUTO TRANS OVERHAUL - FORD AOD article. If referred here by trouble shooting charts or testing procedure, proceed with self-diagnostics. Some circuit tests in this article may also be used by the experienced technician to help bench test and diagnose solenoids. Transmission fault codes are only output in the KOEO Self-Test.

NOTE: In addition to transmission fault codes, engine-related fault codes may be output during QUICK TEST procedure. These fault codes pertain to engine performance and must be repaired first, as engine performance will greatly affect transmission operation. For information and testing procedures of engine-related fault codes and components, see TESTS W/CODES - EEC-IV article in ENGINE PERFORMANCE section.