This is indicating an oxygen sensor high voltage. -This is an emissions fault. Go to YouTube and lookk at everything concerning that code and your car, it is not simple.
The engine model serial code for the 1998 Toyota Supra 12092108.
O2 sensor circuit high voltage (bank 1 sensor 2)
under the driver side and after the pre catalytic converter ( the second sensor). regards.
Trouble code P0340 means:Camshaft position sensor circuit malfunction
Trouble code P0505 means: Idle Air Control System
Trouble code P1300 means: Igniter Circuit Malfunction No. 1
Trouble code P0172 means: System Too Rich (Bank 1)
Trouble code P0401 means:Exhaust gas recirculation flow insufficient detected
The color code is on the sticker which as attached to the of the car from driver's side.
Trouble code P0446 means: Evaporative Emission System Vent Control Circuit
Trouble code P0441 means: Evaporative Emission System Incorrect Purge Flow
Try this http://www.fixya.com/cars/t4081403-98_toyota_camry_srs_airbag_trouble_code