DTC P0135 - Front Oxygen Sensor Heater Malfunction: Condition

DTC is set when ECM voltage is greater than 11.5 volts when voltage is supplied to front oxygen sensor heater. When ECM voltage is less than 5.8 volts when no voltage is supplied to front oxygen sensor heater. Possible causes are:

• Front oxygen sensor.
• Open or short circuit between main relay and terminal "C" (Black/White wire) on front oxygen sensor.
• Open circuit between terminal No. 1T on Engine Control Module (ECM) and terminal "D" (Orange wire) on front oxygen sensor.