Main Relay (Computer/Fuel System): Description and Operation

ECCS Relay:

PURPOSE
The Electronic Concentrated Engine Control System (ECCS) relay provides operating power to the Engine Control Module (ECM).

OPERATION
Battery voltage is supplied to the relay whenever the ignition switch is in the "ON" or "START" position. The relay is grounded through Pin 16 of the ECM. When the switch closes, Pins 49, 59 and 109 of the ECM, mass air flow sensor, crankshaft position sensor and the closed throttle position switch all receive battery voltage.

NOTE: Pin 16 of the ECM also grounds the ignition coil relay.