Data Link Connector: Description and Operation

Diagnostic Connector (STO/STI):

The self-test output and self-test input connectors are both used while performing the electronic engine control Quick Test diagnostic procedure with either a Super Star ll tester or analog voltmeter. When the self-test input connector is jumped to ground, a signal is sent to the electronic control assembly activating the ECA self-test mode. The self-test output connector is used for retrieving output signals from the ECA which appear as numbered codes on the Super Star ll tester or needle sweeps on the analog voltmeter. Codes retrieved from ECA memory represent a malfunction within the EEC system, Fig. 12.