OS2 Heater Circuit?
 

Hello,
I have a 96 SL320 with 133k on it. The MIL came on just as I pulled in the driveway tonight on my way home from happy hour. I took out my scanner and up came the code P0141. "Current for Oxygen sensor heater is outside the limit (approx 0.2-2.0 A) for longer than 2 secs. I am confused as it says OS2 heater circuit malfunction. Do I replace the OS2? Do these things have heaters in them? Any ideas? Thanks for your help!
Brian

Correct wiring is white wires are heater circuit and they are direct connect back to ECU.
You are looking for 1.2-2.2 A draw, so an amp meter in series will be the test.
My suspect would be the heater connector plug under the passenger side rug.. check it for good connection and dirt..this will also be easy access for test point.

Aurthur, thanks for your reply. I replaced the o2 sensor behind the cat, this is what the book said was malfunctioning per the code on the tester. I checked all my wires and they were fine. I cleared the code after repair and it has been 1 full week and no check engine light. This is the second repair I have done using my scanner and I am amazed at how easy this has been. I am glad I have an MB publication though, the generic publication that came with the scanner really doesn't tell you enough to know exactly what sensor is acting up, so I have been very lucky. 134k miles and still going strong with my 104! Thanks again and I really appreciate you being so helpful to myself and everyone else around here, I have learned so much from this forum.
Brian

B
Thank for the Thanks.
..as Cramer would say "BooYaa !!"

That is stock market slang for "Very Good"..

similar situation
 

I have a similar situation MIL lamp is on.
I Scanned for code and was provided with PO161 - (o2 sensar heater circuit malfunction) the sensor I am told is bank 2 sensor 2.
Freeze frames mode shows for bank 2 -3.9 short term and .8 long term..
The car cleared the cel itself..
What is my next step.


s

Rick,
If it cleared itself then I would just let it be until it comes back. When it does just replace the Oxygen sensor that has the bad heater circuit in it. That is all I did. I only have 2 OS2 sensors, but I think your V8 will have 4, My book doesn't have a definition for PO161 since it is only for the inline 6, not the V8. Good luck!
Brian

Thanks Brian,
The check engine light is off and code is storred..
Do you think I should try to clear the code??