Subaru 1998 Legacy Owner's Manual page 110

If this light comes on steadily or blinks while the engine is running, it may
indicate that there is a problem or potential problem somewhere in the
emission control system.
B If the light comes on steadily:
If the light comes on steadily while driving or does not go out after the
engine starts, an emission control system malfunction has been de-
tected.
You should have your vehicle checked by an authorized SUBARU
dealer immediately.
NOTE
This light also comes on in the following cases:
D The fuel tank is completely empty.
D The fuel filler cap is not tightened until it clicks.
If the fuel tank is empty, refill the tank as soon as possiblle. If you have
recently refueled your vehicle, the cause of the CHECK ENGINE warn-
ing light/malfunction indicator lamp coming on could be a loose or mis-
sing fuel filler cap. Remove the cap and retighten it until it clicks. Make
sure nothing is interfering with the sealing of the cap. Tightening the
cap will not make the CHECK ENGINE warning light turn off immedi-
ately. It may take several driving trips. If the light does not go out, take
your vehicle to your authorized SUBARU dealer immediately.
B If the light is blinking:
If the light is blinking while driving, an engine misfire condition has
been detected which may damage the emission control system.
To prevent serious damage to the emission control system, you
should do the following:
D Reduce vehicle speed.
D Avoid hard acceleration.
D Avoid steep uphill grades.
D Reduce the amount of cargo, if possible.
D Stop towing a trailer as soon as possible.
The CHECK ENGINE warning light may stop blinking and come on
steadily after several driving trips. You should have your vehicle
3-10