1998 Subaru Forester BaseFACTORY OEM SERVICE PROCEDURE

Electronic Control Module (ECM)

If a system malfunction occurs, a back-up system within ECM controls fuel and ignition system functions according to preprogrammed values (limp-in mode). This allows vehicle to be driven, but performance may not be optimal.

A self-diagnostic function allows ECM to store Diagnostic Trouble Codes (DTCs) in its memory. If a system fault occurs, Malfunction Indicator Light (MIL) will illuminate to inform driver of system problems and the appropriate DTC will be stored in memory. For further self-diagnostic system information, see TESTS W/CODES article in this section.

NOTE: Components are grouped into 2 categories. First category is INPUT DEVICES, which are components that control or produce signals monitored by ECM. Second category is OUTPUT SIGNALS, which are components controlled by ECM.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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