Sensor question DTC

I have a 1995 C220 Merc Benz. 136k miles.
The check engine light came on and the DTC code is PO141. On the internet PO141 indicates O2 sensor heater circuit malfunction ( Bank 1 Sensor 2)
I am not very knowledgeable in cars. So I apologize for any questions that appear basic.
1. What does "O2 sensor heater circuit malfunction" mean? Does this mean that heater is broken ? Does this mean that just the sensor needs to be replaced or does it mean that other work needs to be done ?
2. What is the part number so that I can price it on the internet?
3. How much should a mechanic in the SF Bay Area,CA charge for replacing this sensor ?
Thanks, Tasleem
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Oxygen sensor is used to monitor if the engine burns the fuel efficiently and completely. There is one (sensor 1) before catalytic converter and another one (sensor 2) after. On V engines (V6, V8, etc.), the exhaust comes out from two sides so there is bank 1 and 2. Your car has only one side (bank 1) and two sensors (1 and 2).
The O2 sensor operates in high temperature. Before it is hot enough, the computer will use more fuel which wastes gas and produces more pollutant. Therefore, a heater is built into the sensor so it can reach high temp pretty fast. P0141 means that built-in heater is not working as designed.
Heated O2 sensor usually lasts about 100k miles. Yours is already ahead of most. The front (#1) sensor may need replacement soon (if it has not been replaced yet).
Solution: replace the sensor and reset the check engine light.
The sensor is about $70 to $100 each on the internet. Check AutoHausAZ.com. It is close to you. Buy the exact fit, not the universal one (cheaper but more labor). The removal/installation is roughly an hour. If your car layout is similar to C280, the sensor 2 is hidden on top of the exhaust pipe. It can be felt but not seen. Once I found the location, it was an easy job (with right tools).
Tasleem Khanna wrote:

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