There are several diagnostic trouble codes (DTCs) that can trip a check engine light on a Subaru Forester. Any Subaru Forester manufactured in 1996 or later has
OBDII (on-board diagnostics 2) system. Many parts stores or local repair shops may scan and read the codes in your Subaru Forester for free with the hope that you'll purchase parts or have your Subaru Forester repaired there. Nowadays, small hand-held
code readers and erasers can be purchased (for as low as $40 to $50) at many local auto parts stores (or online auto parts stores) for the do-it-yourselfer.
Open the driver's side door of the Subaru Forester and look under the dashboard on the left-hand side of the steering wheel (although certain year models may require looking on the right-hand side of the steering wheel).
Plug the OBD II code reader into the DLC and then turn the ignition key to the key-on/engine-off position. This position is two forward clicks in the ignition that will power the Subaru Forester's electrical components without starting the engine. This will also provide portable power to the
OBD II code reader.
Plug the code reader/eraser into the DLC and turn the ignition key on to the key-on/engine off position. The
code reader/eraser will turn on, powered by the battery of the Subaru Forester.
Turn the ignition key two clicks in the ignition. This should be the accessory position (also known as key-on/engine-off) which provides power to the electrical system without the engine running.
