Got a CEL not sure what it means... need help!

[BlueBeast22]

So today driving back home I just happened to be looking at my dash when I noticed a CEL pop up. The car didnt drive any different, I wasnt getting on it just driving normally. So I happen to have a OBD2 scan tool in my car so I hook it up while im driving and the code was P01040 I belive, and it said 02 Sensor CKT no activitiy (bank 1 sensor 2). Not sure what that means but the car was running normal with no issues even with the CEL. I checked my o2 sensor and everything seemed to be fine. The only thing I've done to the car in the past week was change the spark plugs... maybe the connector for the coilpacks came undone? anyways any help would be appreciated.

 

[Captain KRM P5]

typically a "no activity" signal means the sensor is no longer functioning. you could use a voltage tester and see if there is any electrical activity. this code on many cars signifies that the ECU is not getting a signal from the o2 sensor.

 

[BlueBeast22]

yeah well the car is running fine, and I know if the o2 sensor was bad the car would be running like s***. Maybe it was just a glitch or something?

 

[122 Vega]

The second O2 sensor has nothing to do with how th e car runs, the AFR is determined off of the first O2 sensor in the manifold. The second only determines if the cats are present and working. If however you continue to drive with the CEL on, it will go into "safe mode" and run really rich to protect the engine. It will usually do this after about 150 miles with the CEL on.

You've been catless for awhile without a CEL, then it's possible if you changed type or heat range of spark plug the car would be running different for long enough for the CEL to be tripped. I'd just reset it then see if it comes back.

Britt

 

[BlueBeast22]

Yeah I used the same type of plugs though, NGK BKR7E copper plugs. Not sure but I do have a mil eliminator on my 2nd o2 sensor on the downpipe because im running catless, and Ive never had a CEL because of that. Anyways I erased the code and it hasnt come back so far.