On-Board Diagnostics System

A: FUNCTION





The on-board diagnostics system is capable of detecting any trouble which has occurred in any of the following input and output signal systems.
The results of on-board diagnostics are displayed by flashing ATE Temperature indicator lamp.
- Repeated flashing at 4 Hz Error such as battery trouble
- Repeated flashing at 2 Hz Normal
- Output of trouble code Check faulty portion
- Continued lighting of lamp Error in inhibitor switch, idle switch, or wiring

B: OPERATION OF INDICATOR LAMP





On starting the engine, AT OIL TEMP indicator lamp illuminates as shown below. If any trouble occurs, the lamp continues flashing until ignition switch is turned to ON position (engine turned off).





C: TROUBLE CODE

D: SELECT MONITOR
Various data and ON/OFF signals being processed in the TCM can be monitored by connecting the select monitor to the select monitor terminal located under the instrument panel.

E: ON-BOARD DIAGNOSTICS (OBD) SYSTEM
- The on-board diagnostics (OBD) system detects and indicates a fault in various inputs and outputs of the complex electronic control. CHECK ENGINE malfunction indicator lamp (MIL) in the combination meter indicates occurrence of a fault or trouble.
- Further, against such a failure or sensors as may disable the drive, the fail-safe function is provided to ensure the minimal driveability.
- The OBD system incorporated with the vehicles within this engine family complies with Section 1968.1, California Code of Regulations (OBD-II regulation). The OBD system monitors the components and the system malfunction listed in Engine Section which affects on emissions.
- When the system decides that a malfunction occurs, MIL illuminates. At the same time of the MIL illumination or blinking, a diagnostic trouble code (DTC) and a freeze frame engine conditions are stored into on-board computer.
- The OBD system stores freeze frame engine condition data (engine load, engine coolant temperature, fuel trim, engine speed and vehicle speed, etc.) into on-board computer when it detects a malfunction first.
- If the OBD system detects the various malfunctions including the fault of fuel trim or misfire, the OBD system first stores freeze frame engine conditions about the fuel trim or misfire.
- When the malfunction does not occur again for three consecutive driving cycles, MIL is turned off, but DTC remains at on-board computer.
- The OBD-II system is capable of communication with a general scan tool (OBD-II general scan tool) formed by ISO 9141 CARB.
- The OBD-II diagnostics procedure is different from the usual diagnostics procedure. When troubleshooting OBD-II vehicles, connect Subaru Select Monitor or the OBD-II general scan tool to the vehicle.