check your voltage output from your battery with the car running, it should be between 13 and 15volt, had the same problem altenator wasnt putting out, it was going bad, replaced altenator problem went away.
i had the same code 98 es300 turned out to be my altenator not putting out enough voltage. check you voltage form your battery it should be between 13.5 and 15.5v volts. changed my alternator problem went away. hope this helps.