O2 sensor codes. Three at once (P0131, P0141, P0151)
Saw my first check engine light in the two years of owning the car. 102k miles 2004 e320.
Read the codes and there were three:
P0131 - pre cat bank 1 o2 sensor low voltage
P0141 - post cat bank 1 o2 sensor heater circuit malfunction
P0151 - pre cat bank 2 o2 sensor low voltage
My question is it likely for all three sensors to fail at once in a day? I find it odd.
Is there anything else that could have caused these codes to pop before i start replacing sensors?
//EDIT
Called one of my friends who is a mechanic at a BMW dealership and he said it may be the battery without me even mentioning anything about the battery.
Have had this problem for a few months with it, where if it sat for a day or two without being driven i would get a "Battery protection: Convenience functions temporary unavailable" warning that would go away after driving for about 10 minutes.
Could a dying battery lead to a failure in the O2 sensors readings?
//EDIT 2
Took the car out for a drive after 5-6 hours. CEL is gone. Will keep monitoring.
Thank you very much!
Last edited by zaezzz; Apr 18, 2018 at 01:48 AM.




Bring up the voltage on the instrument cluster (internet search). If under 12.1 at rest and engine off, check the main battery and replace if necessary.
Thank you for your response.
As for what is going on now. I went and bought a new battery about a month ago. Still kept on driving with the old one for about two weeks to take notes of the behavior of the car. The CEL would go on at random times, during a long drive, or a 100 ft after starting to drive, and not on every drive, maybe every third. It would sometimes go off when the car sat overnight, sometimes it would not.
I replaced the battery after two weeks, seemed fine for a couple of days and then it started again. CEL on after driving for 4-5 minutes, sometimes no CEL after driving the entire day.
Also the old battery was checked at Interstate, it was a little weak at startup dropping to 10.5V or so. The alternator performed fine holding the voltage at 14.0V-14.2V.
Called a friend of mine, will bite the bullet and replace all O2 sensors hoping it will solve the problem.
He is saying it may have started happening due to bad gasoline. I told him i filled up at arco a couple of times and he's saying it's probably due to that.
Time will tell, hoping for the best.
Thank you!
Last edited by zaezzz; Jun 22, 2018 at 05:57 PM.

Have not checked the aux battery. Might be a good idea.
Today i read the codes again after a CEL light, does not look too good:
P2082-08: Left 02 sensor, before cat : Short circuit in the signal line (P0151)
P200F-08: Right 02 sensor, before cat: Short circuit in the signal line (P0131)
P207F-01 Left 02 sensor, before cat: Aging, correction variable exceeded: Delay time too long (P2098)
P200C-01 Right 02 sensor, before cat: Aging, correction variable exceeded: Delay time too long (P2096)
P20C2-04 Right 02 sensor, after cat: Open circuit in sensor heater line (P0141)
P2009-08 Right 02 sensor, after cat: Heating capacity is too low(P0141)
I have this bad feeling that the person that replaced my engine mounts... after seeing him use a crowbar to push things around may have had something to do with this. Don't want to blame, but it's a feeling..
Have to leave now, will dig more later.
Thank all for your insights!
Will update once the sensors are replaced.
On a more positive note, a couple of weeks ago my radio started cutting out every 5-15 seconds for anywhere from 1-10 seconds. After digging for days and taking apart everything in my trunk i finally isolated the problem to the busted tele aid module which i ended up bypassing with one of those optical bypass loops. Radio now works great. Super happy!
Also, whilst taking apart my trunk i found the cause why my Dynamic seats where not working. The cause was a cracked hose going from the air pump to the air reservoir which i removed, shortened and plugged back in. The seats now work great as well.
Thank you all for your responses! Learned a lot about my car in this past week.

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Thank you for your insights. Wish i had more time to replace them one by one.
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Update: Got all 4 sensors replaced at a cost of 600$ in parts and labor. Engine light gone, made the trip without problems and car is still running fine after about 4000 miles.
edit: maybe I’ll start with the primaries




