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95 SL320 Oxygen sensor and Oxygen sensor probe

My 95 SL 320 has an Oxygen sensor mounted before the Catalytic converter and another one which is called an Oxygen sensor "Probe" after the Catalytic converter. Some months back the CEL came on and code P0141, "O2 sensor heater circuit bank 1 sensor 2" was displayed. I cleared the code and everything appeared to be OK for a while. The CEL came back on again yesterday and I am planning on replacing the Oxygen sensor before the Catalytic converter. I have reason to believe that it is the one that has the heating element. Now I am curious about the function of this O2 sensor "Probe". MY 129 service DVD does not appear to address this part. At least I have not been able to find it yet. Any tips will be appreciated, Thanks Peter

Reply to
Peter W Peternouschek
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You have OBD-II setup... they measure the before and after cat exhaust to gauge the performance of the cat converter. It seems that your O2 sensor died because of the heating element inside the O2... these sensors are self heated to get fast and accurate performance when cold.

Reply to
Tiger

Unfortunately the problem appears to be intermittent. I am still trying to verify which of the two O2 sensor causes the problem. I was able to do some more investigation within the 129 DVD ETM section. There is reference to an O2 sensor 1 before TWC and an O2 sensor 2 after TWC. I can only assume that TWC refers to the catalytic converter. O2 Heater activation occurs at ECT (engine coolant temp) >80C for O2 sensor 1(before TWC) and

Reply to
Peter W Peternouschek

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