1999 Q45 throwing codes 138 and 139

[maxnix]

What exactly was involved in the reset?

[poweroptions]

I don't 100% understand these cars, but it involved the length of time activating the rear O2. It was in Infiniti Sewell for less than 45 minutes when it was driven back out of service to me.

[maxnix]

Interesting as I don't understand activating the O2 sensor. Either it works, or kind of works, works poorly, or doesn't work due to wear.

Wonder if it was unplugged?

Both primaries? Secondaries? All 4?

Did your mileage drop suddenly recently?

Curiouser and curiouser.

[poweroptions]

Brian, I did have decreased fuel economy. The car usually gets 22-24 mpg and it had dropped to 17-18 on the highway and was not as peppy as usual. The Infiniti fellow said the ECM was reprogrammed. I might have used the wrong term earlier when I said ECU. Whatever they did it has it's pep back.

[maxnix]

If I recall correctly, there was a TSB about that issue. Don't have them with me so cannot verify. Impressive if they reflashed it with the Consult II.

What does it say on the RO?

[poweroptions]

It says DTC/ECM reset N/C

[96Qowner]

This is the TSB:

http://www.infinitihelp.com/Ow...8.htm

[maxnix]

No page A2.

[poweroptions]

WOW! What great service from you NICO guys! I'm turning my mechanic George onto this site as he is a Nissan man. We are into our old Fords,TBirds,Lincolns but he convinced me to go Japanese after my Mercedes 500S drove me to the poor house. What a crap car it was. When Mercedes said it needed a whole new wiring loom for $8000 at 72K and the A/C set me back $5000 and broke again 2 weeks later. I dumped it and lost $$$$$$. NEVER AGAIN Mercedes Benz!!!

[attofarad]

I wanted to say THANKS to everyone and their input. Infiniti reset the ECU and 500 miles later no stumble and no MIL "on". Tech said this is a usual problem with 99-01s and there was no charge. They luved my car and were blown away with the condition it is in. Wanted me to trade it in but I said no way. I'm due a new pickup next. patrick

Well, that is what a recall service like this should cost, no money and little of your time. I asked my local Infiniti dealer about the TSB, and they wanted $150 to see whether it applied to my girlfriend's QX4 (I know it does). I didn't have it done, and I will not be buying an Infiniti in the future, as long as this is the only dealer around here.

[maxnix]

Many dealers in the Bay area. Need to find a good one. If it is out of warranty, owner must pay for diagnosis. Don't know why this would be news.