History:
SES light cam on 2001 SE Auto, took in for repairs, replaced oxgen sensor and reset ECU.
codes are:
P0138 - Heated Oxygen Sensor 2 Circuit High Voltage (Bank 1)
P0139 - Heated Oxygen Sensor 2 Circuit Slow Response (Bank 1)

1 week later light came on agian, took it in any the said they (Local Nissan Dealer)needed to upgrade software in ECU. They did that.

1 week later light back on again. Then went off the other day, now is back on again the this time the day before I have to have the emissions tested.

Question:
IS there something else that they should be looking for, other psossible solutions for these codes, i.e. ground wires( my wifes eratic driving)
Help has this happened to anyone else.

 

Did your service order SPECIFICALLY say what they did, ie which 02s were replaced and what version software they reflashed?

Here is what they should have did:
http://maxima.theowensfamily.com/tsb/NTB02-051a.pdf

 

It does state that they replaced the B2 O2 Sensor part number 226A-4L713
and reset MIL check light.

There is no mention of what software was flashed

 

So, they only changed one?

I'd print out that TSB and go in there and verify they followed it EXACTLY, ie replace both and reflash the ECU. To make sure you have the latest ECU reflash, ask them to print out the before and after ECM part number.

By your description, they didn't know about the TSB the first time and maybe the second time, they failed to read the TSB and follow it verbatim. My guess at least.