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Basic Diagnostic Procedure

NOTE: Subaru Select Monitor (SSM) or an OBD-II general scan tool must be used to perform basic diagnostic procedure. Follow scan tool manufacturer's instructions for proper operation. Communication with vehicle's on-board computer is through the OBD-II Data Link Connector (DLC). See Figure .

After performing procedures in BASIC DIAGNOSTIC PROCEDURES article, this is the starting point for utilizing the self-diagnostic system for determining computer-related problems. After performing necessary tests as described in the basic diagnostic procedure, if no codes are indicated and driveability problems still exist, see SYSTEM TESTS  .

NOTE: Check for applicable Technical Service Bulletins (TSBs) before proceeding. DO NOT perform the following procedure if driveability conditions are not present. DO NOT turn ignition "OFF" during the following procedure or clear DTCs unless instructed to do so.
  1. Verify customer complaint and conditions under which fault appears. Attempt to start engine. If engine starts, go to next step. If engine does not start, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).
  2. Check to see if MIL (CHECK ENGINE) light on instrument cluster illuminates, indicating a system fault. If MIL (CHECK ENGINE) light illuminates, go to next step. If MIL (CHECK ENGINE) light does not illuminate, go to SYSTEM TESTS  .
  3. Turn ignition "OFF". Prepare Subaru Select Monitor (SSM) by inserting appropriate diagnostic cartridge and connecting diagnostic cable. Connect SSM or OBD-II general scan tool to data link connector (DLC). Turn ignition and scan tool on. Retrieve diagnostic trouble codes (DTCs). If any DTCs are stored, save freeze frame data using scan tool, see FREEZE FRAME DATA  , then go to next step. If no DTCs are stored, although MIL (CHECK ENGINE) light is illuminated, go to SYSTEM TESTS  .
  4. Perform required repair by using procedure associated with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If an automatic transaxle DTC is set with other codes, perform basic A/T checks and repair other DTCs first. Basic A/T checks consist of transaxle fluid level, differential fluid level, transaxle fluid leak, differential fluid leak, stall test, line pressure test, transfer clutch pressure test, time lag test, road test and shift characteristics only. See appropriate AUTOMATIC TRANSAXLE OVERHAUL article in AUTOMATIC TRANSMISSIONS.
  5. After repair, perform clear memory function. See CLEARING DIAGNOSTIC TROUBLE CODES  .
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