The Check Engine Light may illuminate due to an O2 sensor heater fault. Most commonly the affected O2 sensor will need to be replaced to correct this concern.Google+
Car Problem Reports
Lexus GS300 Check Engine LIght With Code P0135, P0141, P0155, or P0161
Lexus GS300 Problem
Average Mileage: 109,105 mi (62,500 mi - 165,000 mi)
Visitor, 1998 Lexus GS300, 100,000 mi
check engine light on. Replace the o2 sensor...still the light stays on.
Visitor, 2002 Lexus GS300, 101,000 mi
the O2 sensor was replaced
Visitor, 2004 Lexus GS300, 110,256 mi
Vsc and check engine light on. Advanced auto said bad o2 sensor.
Visitor, 2000 Lexus GS300, 120,000 mi
Check engine light came on after refueling, then driving for 40 miles. OBD-II reader shows P0141.
Visitor, 2002 Lexus GS300, 98,340 mi
Diagnosed as a PO 141 02 heater B1S2. Not yet fixed.
Visitor, 1999 Lexus GS300, 98,000 mi
check engine light came on. code P0155, just had oil change.