To read Diagnostic Trouble Codes (DTC's) the test connector for the EEC system must be used. This connector is known as the Assembly Line Diagnostic Link (ALDL) connector on vehicles with EEC-IV ignition equipped engines, or the Data Link Connector (DLC) on all other models (EEC-V), is located in the passenger compartment. It is attached either to the underside of the instrument panel, and is accessible from the driver's side of the vehicle, or it is under the hood near the power distribution box.
The connector is trapezoidal in shape and can accommodate up to 16 terminals.
See Figure 1