The maintenance light on a Toyota 4Runner comes on when regular maintenance is required. This "Check Engine" light can also indicate a problem with a variety of vehicle systems. On the 4Runner, the light, located on the dash, is in the shape of an engine. To reset the light, first perform the scheduled maintenance and then use an OBD reset and scan tool, available from Toyota.
Locate the OBD port on the left side of the fuse panel of your 4Runner. There is only one port large enough to accommodate the plug of the OBD tool.
Connect the OBD plug into the OBD port on your 4Runner.
Turn the ignition key to the "II" position.
Wait for the maintenance light to go out.
