Divine

Okay, yet another problem for you guys (I love this place)

I'm sorry for the looong story leading up to this, just scroll past the break to get to the main point and skip the drama...

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I bought my Max from a college girl a in Feb.- check engine light was on (yeah yeah, I know I bought a car w/ CEL on, but I trusted her ) She says that she had just had a diagnostic done and it was because the O2 sensor had just gone out, so I had her bring down the price on the car to $4500 from $5000 and figured I could just replace the thing easily...

Well, I hadn't found the .org yet, and had no clue that you could pull codes on a Max yourself. So I paid $30 to have a diagnostic run on it (AutoZone here dosen't do it free anymore) to see which sensor is bad and it gives me these codes...

P0135- O2 Heater CKT Bank #1 Sensor #1
P0325- Knock Sensor #1 Malfunction

A bad knock sensor too? - Well, I later found out that the KS code can show up as a ghost code, but w/ the mileage (158,000) I figured I'd replace that too and it turned out to be craked.

As for the O2 sensor, I was now looking to see where Bank 1 Sensor 1 was located and found a site which apperently does not apply to Maximas (can't find the URL now) that said Bank 1 Sensor 1 was the front Left Sensor.

So I toodle down to AutoZone and bought their last Front Left O2 sensor - BOSH OEM replacement part ($84), and ordered the KS from NAPA ($180).

In the mean time I find Maxima.org and these forums and find out you can reset the ECU and pull codes yourself.

After I got the parts, and spend a whole day at my mechanic's house changing the KS and O2 sensors, also cleaned the fuel injectors and changed the oil- We reset the CEL and I go on my marry little way...
Well, On the way home the CEL pops back on! I get home and pull the codes and get:

09 01 - front right htd O2 sensor heater

OMG- Now I find out that it is the front RIGHT that's out, not the LEFT that we just changed!- So I call all over town and no place has this part in stock and only NAPA will special order it for me- I get them to match AutoZone's price and order the Bosh OEM Replacement O2 Sensor.
When I go to pick up my part today, they hand me a NAPA Brand O2 sensor, which looked way different from the Bosh that was in the car, the guy there tells me "well it will work better than a Bosh, it's what Nascar uses"- I just say whatever and head over to have the thing changed.

Well, we go through all this and get the Front Right O2 changed and reset the ECU. The light was off on the first start, but on the second start it came back on.. pull the codes and get 09 01 again!!!
Reset it again and on the SECOND start again it pops back on the CEL. It keeps poppong up the CEL on the Second start w/ the same code.

We have checked the connections and I really do not think that the new O2 sensor has an out heater! The only thing that we can come up with is that there may be a problem w/ the ECU not even sending the signal to the heater to turn on, and then saying that it is not working- does that make sense? Could it have somethig to do with the NAPA brand sensor (doubt it)? I'm all out of Ideas and energy at this point.

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To get to the point for those who did not want to read the long story above...

I got code 09 01 for the front right O2 sensor heater, replaced the whole thing and I'm still getting the code on each SECOND start after resetting the ECU. Would this then be a problem with the ECU itself since there should be no problem with the New O2 sensor?

Please give me any advise or opinions you have, Thanks so much for your time and help!

Divine

Today I took out the Napa O2 sensor.
Replaced it with the old one from the front LEFT (which shouldn't have been bad if we changed the wrong one first time around) tried reseting the CEL. Once again on the SECOND start CEL comes back on. We tried unplugging the battery to see if that would reset it. Nope CEL on the second start again. So, the last thing that will prove that it cannot be the Sensor giving the code is to get a brand new Bosh/ OEM in there, which will happen as soon as they get one in.

Do you think it could be possible that the girl who had the car before me could have ran it for so long with the CEL on for the O2 that it somehow burned into the computer's memory?

Ever heard of anything like this happening before?

Anyone have any ideas that may help me out?