Codes p0138 and p0139, ecm reprogram ?

[kenko95]

I have a 2000 I30 (170K) and the SES light came on few weeks ago. I had the codes read at autozone and p0138 and p0139 came up. They told me that its the o2 sensor. I researched on the web and I also read the TSB and it tells you to 1. replace 2 o2 sensors (red & white) 2. reprogram ecm

Couple questions

Can i replace the o2 sensor and clear the codes myself(I can borrow the tool from Autozone) or do I have to have the dealer perform the reprogram of the ECM($125)?

Will the SES light go off by itself after I replace the o2 sensors?

Is there a benefit to having the dealer reprogram the ECM?

Is it necessary?

My car has never been to the dealer for service before. I do all the maintenance myself. (the ECM has never been reprogrammed). One thing I did couple days before the ses light came on, I replaced all the spark plugs to NGK iridiums (it was cheaper than the OEM ones I usually use)

I hope someone can shed some light on this reprogamming of the ECM subject.

I have also noticed poor gas mileage. I think the systems default is to run rich.

I already bought the o2 sensors from a infiniti dealer from the internet.

Thanks in advance for you help.
Modified by kenko95 at 12:50 AM 7/22/2006

[fanedandu]

same scenario happends to me but with 4 pins Bosch spark plugs after 2 mos. of replacing them. No answers to your questions yet. I have only p0400 & p0138 code by Autozone reader.

[maxhopper]

I was under the impression that the ECM reprogram was neccessay if you had codes P0420/P0430 for the precats (but I could be wrong). Can you copy and paste the TSB into this thread? It'd be most helpful.

Yes the SES should go out after replacing the faulty O2, and the car goes though a drive cycle and sees the proper values.

You are correct about the defauly running rich with an O2 failure.

[fanedandu]

I just replace the WHITE sensor, the engine "feels" better - no fine vibrations in steering wheel/body on idle. The SES is still on......after a mile of driving....I remove the + whire from battery (..like a comp. reset)...didn't work...so remains to try the screwdriver or autozone methode. Mine is 1999 I30.

[maxhopper]

The ECM screw reset should work for you.http://vbxmaxima.8m.com/ecu.html

[kenko95]

Here is the TSBhttp://www.infinitihelp.com/Ow...7.htm

The above site has all the bulletins posted but not much of posts to read and learn.

Anyways, I just decided to replace both sensors at home and I didn't want to wait for the SES light to go off, I went to autozone and they cleared the codes for me. So far so good.

The only thing I'm worried about is whether there is a benefit to having the ECM reprogrammed by the dealer. Will it give me better gas mileage?

[maxhopper]

Thanks for linking the TSB. I would go ahead and have the ECM reprogrammed. Since it doesn't specify what values it would change, it's hard to tell what benefits would be gained.

[fanedandu]

in short: O2 white wire replaced (code p0138); SES light still ON after deconecting for about 2 hours the + from battery; went to Autozone (best of the best!!!! store) re-check the codes (I head p0400 & p0138) ....remains only p0400....BINGO! we just reset the p0400 by the handheld reader..... SES went OFF & after a day is still OK! but.....the stearingwheel fine vibrations are still present.... maybe is normal....