Infiniti P0420 P0430 and P1610 after battery replacement

May 10, 2005
Jupiter, Fl
A friend of mine took my FX45 on a trip. While they were away, the battery died. They had the car jump started and took it to an auto parts store that replaced the battery for them. On the way home the SES light came on. They also said that after the battery was replaced, the car died in traffic, but then restarted. Also at a restaurant about 500 miles from here the car cranked, but wouldn't start. After going inside and calling me, they walked back outside and it started normally and they finished the last week of their trip. They drove 800 miles after the battery replacement, they said the gas mileage seemed the same.

When I got the car back, the SES light was still on with codes for P0420, P0430 and P0610 (or maybe P0611). The car has just a hair over 200K on it. It seems unlikely to me that both cats would go bad at the same time. Also, the NATS error seems odd. I looked around for obvious vacuum leaks, etc. I have not looked at the battery closley yet, aside from making sure the terminals were tight - the receipt shows that it is another AGM battery comparable to the one that had been in it for the last 5 years or so.

I tried swapping the MAF with a known good MAF and reset the codes. Within a few miles, the P0420 and P0430 were pending.

Is there any common thing that causes this? I'm not generally one to blame the last guy who worked on it, but I would like to eliminate anything that could be related to the battery swap or from being jumped. The only other things that come to mind are a vacuum leak or something similar that is common to both banks, or maybe a bad ground somewhere.

Watching real-time data as I drove, I didn't see anything out of line. The front 02 sensors are wideband, so I can't directly compare them to the rear.

At idle, the car smells kind of rich. It seems to run perfectly. Pulls strongly to redline in the first few gears. My inclination was that there isn't any sort of blockage on either side.

Coolant temp sensor was reading about 90c, which seemed reasonable. Air temp was reported correctly. short and long term fuel trims seemed to be in range, but that doesn't mean the whole system could be out of whack due to a bad sensor reading.

His only thought was that they drove very easily for a few thousand miles compared to my normal trailer towing and higher speed driving.

Any suggestions? Do I ignore it at 200K? To be honest, one of my few concerns is how close the front cats are to the exhaust ports. I don't know if this is one of those Nissan designs that cat material can get sucked back into the engine if they fail.

Also, the NATS thing seems odd. I don't want to get stranded somewhere.
V6 or V8 I don't believe those motors had the cat suck back problem....
That was the 4 cylinder motor issue.

If your fuel trims short and long term are good... That's a positive sign.

Though your cats could still be going bad. Mine were shot at 240,000 miles and replaced. If my memory is right the first code showed up a little after 200,000- miles.

My car is a 2008 Nissan Altima VQ.
My 09’ Camry had the dreaded “death code” or P0420. Replaced aft cat O2 sensor and cleared light. It passed PA Emissions fine, Infiniti build the catalysts out of chewing gum, bailing wire and a prayer to the automotive gods. At the milage the OP mentioned, no, likely doesn't have the catalyst brick ingestion problem. Likely, the catalyst is simply tired.

Swap out the post catalyst 0² sensors first. If it doesn't dial in to normal and lights the MIL, it's going to be the catalyst(s) that failed. I've personally never seen a Nissan with over 170k on the clock that didn't have a lazy convertor.
Lazy is fine. I just don’t want ceramic dust eating my engine. We don’t have emission tests here. It surprises me that both of them literally went bad at the same exact time, although I guess they’ve lived pretty similar lives.
Is it possible that as the battery died they had mis-fires. un burnt fuel will eat the cat in a heart beat if they are old. got to remember, these cats are 3 stages, first stage gets rid of direct combustion gases, the next stage cleans up what the first stage sent, and the third, cleans more. the rear cat only monitors the efficiency of the first, but can contribute to fuel trim tweaks in closed loop operation. i don't see ceramic junk getting back i your engine, unless there is a physical hole or leak that messes with back pressure in the exhaust.
Is there any common thing that causes this? I'm not generally one to blame the last guy who worked on it, but I would like to eliminate anything that could be related to the battery swap or from being jumped

Was 12 volt power maintained to the vehicle ECU and BCU and other electronic modules while the battery was disconnected?