Electronic Control Unit (Ecu)

The ECU consists of a microcomputer, inspection light, a diagnostic mode selector, connectors and wiring for voltage signal input, voltage signal output and power supply. The unit is not serviceable and should not be opened. Inspection light is provided on side of unit so system operation can be checked. The control unit contains memory and logic circuits that enable it to interpret sensor inputs and control various engine systems.

Continuous fused battery power is provided to ECU terminal No. 58 (No. 46 on G20). Battery power to drive ECU internals is provided through the ECCS relay which is energized by the ECU when the ignition switch is turned to the ON position.