the check engine light came on in my mercury mountaineer that read low heated and heated oxygen sensor for the sam sensor. what can cause this

Can you post the code cuz that description im not aware of. Is it a heater circuit code for a oxygen sensor?

p0152 heated oxygen sensor bank 2 sensor 1 and p2197 lack of heat oxygen sensor bank 2 sensor 1

Replace the sensor. bank 2 sensor 1 is sensor before the converter on the drivers side.

http://www.ebay.com/itm/2003-2004-MERCURY-MOUNTAINEER-NTK- NGK-O2-OXYGEN-SENSOR-/350412935212? pt=Motors_Car_Truck_Parts_Accessories&hash=item51963d102c&vxp= mtr

P0152 MERCURY - O2 Sensor Circuit High Voltage Bank 2 Sensor 1

Possible causes - Faulty Front Heated Oxygen Sensor Bank 2 - Intake air leaks may be faulty - Exhaust gas leaks - Front Heated Oxygen Sensor Bank 2 harness is open or shorted - Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection - Inappropriate fuel pressure - Faulty fuel injectors

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed- end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

When it sets a heater circuit code circuit for just one sensor ya just put the sensor in it they are not expensive and there is no need for extensive diag.