Diagnosis Code

[BISCUT]

Old thread on Nissan Sentra 1.8 O2 sensor replacement. Posted this on that thread but probably won't get seen so posting here.

After battery reset and new O2 upstream the check engine light came back on. I get 2 codes. One is EVAP (Po455 8) and may be due to the gas cap not seeming to fit correctly. New gas cap ordered.

Second code is P2A00 0 Bank 1 which is 02. My gas mileage is 31 mix and 35 highway so it's working. Before the new O2 it was around 18 MPG mixed driving. Bank 1 is upstream and Bank 2 would be the downstream O2 correct?

Surprisingly there were no other codes on the complete scan. I figured there would be a few!

 

[Leo99]

Since you have an inline 4, you only have bank 1. If you had V6 engine, one side of the V is bank 1 and other side is bank 2. In other words, Vx engines have two upstream O2 sensors.

Reset the code and see if it comes back. Maybe it will take your computer a few miles to learn the new trims.

 

[The Critic]

Since you have an inline 4, you only have bank 1. If you had V6 engine, one side of the V is bank 1 and other side is bank 2. In other words, Vx engines have two upstream O2 sensors.

Reset the code and see if it comes back. Maybe it will take your computer a few miles to learn the new trims.

Clearing the codes is not always adequate. On Nissan's you need to use a scan tool to also clear the mixture ratio self-learning value after any O2 or A/F sensor replacement.

 

[Leo99]

Clearing the codes is not always adequate. On Nissan's you need to use a scan tool to also clear the mixture ratio self-learning value after any O2 or A/F sensor replacement.

Can you pull a fuse or disconnect the battery to force a relearn?

 

[The Critic]

Can you pull a fuse or disconnect the battery to force a relearn?

Not sure, I have never tried. For Toyota, disconnecting the battery cables does reset the fuel trims.

 

[BISCUT]

Once I clear the 12-18" of snow off the cars and snow blow the driveway tomorrow morning I will disconnect the cables and reset the code and see what we get.