Self-Diagnosis Function
WARNING: This page is about a different car, the 1988 Subaru RX, 1988 Subaru GL-10, 1988 Subaru GL, and 1988 Subaru DL. However, it is still accessible from the selected car via links, so may be relevant.
The SPFI control unit receives input information from various sensors and produces output information for driving the fuel injector, fuel pump, etc. Also, it examines all input and output information and compares it to predetermined values or ranges. If a predetermined level is not satisfied or a fault is found, the warning light is illuminated.
The self-diagnosis function has four modes. U-check mode, read memory mode, D-check mode and clear memory mode. See TROUBLE SHOOTING CHARTS in this article. Two connectors (read memory and test mode), two lights (ESC and oxygen monitor) are used. The connectors are for mode selection and lamps monitor type of problem.