We have had a problem over the last couple of years of the G37 going into limp mode. I would change the brake light switch and got it working for several months until one day limp mode reappeared. since then I have topped of fluids, cleaned MAF sensors, cleaned throttle body,
changed plugs and etc. which would last for several weeks and go back into limp mode. I have read everything I could possibly find to try and solve this mystery. We do not have an Infinity dealer where we live, so we took it to the Nissan dealer and they could never see a code or CEL. My son is moving to Austin Texas and drove his car there and the car went into limp mode about six times and he would stop, turn off the car, wait five minutes, get going again and have it bounce back into limp mode again and again. I even installed a quick disconnect on the negative battery terminal to make it easy to disconnect the battery. He got up the next morning and drove it to the Infinity dealership (naturally it drove fine) They kept it and drove it fifty miles and it would never go into limp mode and still no codes or warning lights.They said the only way to fix it would be if it threw a code. Since he will be traveling back and forth from Louisiana to Austin for the next couple of Months, I told him to trade it even though he is about to start a new job and will need a reliable car. We hate it because his car looks great inside and out and runs really well when not in limp mode. He is thinking of trading for a low mileage QX50. Sad to have to get rid of a perfectly good car because they are unable to fix it, just hope the newer model doesn't start the same thing. Infinity needs to address this problem since it seems everyone is fighting the limp mode problem. Sure enjoyed the G37 sedan, sad to have to let it go.

 

There's nothing worse than an unreliable car, especially when another family member is trying to rely on it. But that is a super-weird problem because "limp mode" is the last resort that the car's computers switch into and should only happen in connection with several serious error codes, which your Nissan dealer would have found. So that makes it even weirder.

Tell us what happened when the car went into "limp mode". Any warning messages on the dash? Check Engine Light? Sudden slowing or stuck in 1st gear?

I think we can safely say that there's something seriously wrong with that specific car and not the entire Infiniti line of vehicles. Pretty sure you feel that way too because you're thinking about a QX as a replacement. If more people had been experiencing that exact problem you would have found an answer in these forums, or there would have been a recall.

 

Thanks for your comments and even though I drive a C7 Corvette for myself, I love that G37! Great styling, plush fine interior, and a V6 that screams when needed. The limp mode can happen at any speed and is totally random. My son drove his car from Louisiana to Austin Tx at 70 & 80 mph the whole way until 25 miles outside of Austin the car lost power and slows down even if you put it to the floor, the engine will not rev up. Once in town traffic it merely slow rolls to about 15mph . the only thing I have found to do is pull over and turn the car off for five minutes or so or remove the negative terminal off the battery to get it to reset the computer. But this has been going on for nearly 2 years and sometimes go for months without incident but seems to be getting worst. It never gives any warning lights, check engine light, or throw any codes out that a mechanic can see. I have googled the subject and read many similar experiences on this forum, there definitely is a problem. I talked my son out of the QX50 primarily because of that quirky transmission they have coupled with that little four banger. Infinity will remain one of our favorites and look forward to their future offerings and meanwhile I will continue to learn all I can about this limp mode syndrome in hopes of helping someone resolve it if it should appear in their car. Thanks for allowing me to vent a little.

 

Sorry to hear about your son's problem
I am assuming this was purchased as a used vehicle?
Prior to getting rid of it, next time he is near an Infiniti dealer, have the dealer run the VIN number to obtain the entire vehicle service history. Where was this vehicle originally purchased?
Was this vehicle ever involved in a flood with a "washed" title?
The problem could very well be in a wiring harness connector with a corroded pin?
Very time consuming to locate and figure out.
If this vehicle was originally purchased in another state and a search discovers any severe weather incidents, then yes, unless he has the time to inspect every wiring harness connector under the vehicle it may be best to just get rid of it.
Just my $.02
Good luck

 

hey sorry to hear on your woes..im just chiming in because i had a friend with a g35 that had vaguely similar issues and it turned out his car had been in a flood with previous owner..had to do a lot of digging, but somehow he found out..while it was not quite as bad as your situation, it was intermittent..however, he really loved the car..like in a questioning manner lol...and had a bunch of mods etc..so over time and multiple wiring replacements, the car eventually worked perfectly..so just fyi...Also, not sure on this and more knowledgeable people can chime in, but if you are unplugging battery each time, wont the codes get erased? good luck with it all and hope u resolve

 

He can usually reset the computer by turning the car off for five or ten minutes, then restarting. He has had infinity check the car when he has not removed the negative and they still were unable to see any codes and I have a blue driver that I used to check right away when it would go into limp mode and still no codes. Out of desperation, he traded his beloved G37 for a new 2021 Acura. Thanks for the input.

 

I'm having the same exact issue, and son was going to take the car to college. Now I can't rely on it, Infiniti dealer has had it 4 separate times and is unable to fix it. TB clean, flash ECU, swap MAF sensors and replaced intake that had a hole in the plastic. Still happening and super frustrating. 2010 w/ 145k miles

 

Just throwing a random throught out there, but do you live near fields or farmland? Any chance mice have been gnawing at wiring and chewing through things?

Maybe check for signs for mice (droppings or nesting ect) in airbox, hell, sometimes they get into the blower area where the cabin filter is. They really can cause havoc to a car's electrical components. Can happen during winter storage, or long resting periods, or even without long resting periods if you live near fields and farms.

 

I've had this happen, had to get the bank 2 wiring repaired because of mice. No shop seems to want to look at this possibility on bank 1 - og shop that fixed it, nor the dealer. All moneysucking scumbags. Im going to have to tear into the car and look for myself. You may be right. It is intermittent though unlike when the rodent damage happened the first place and the car wouldn't even start.

 

Sorry to hear that, that's brutal. I really hope that is not the case here, but now it seems a bit more like a possibility. Check your inbox, i hope any of that info is of assistance to you. If not, sorry, i wish i could be of more help. Its a disgrace that even the dealer won't help when you are willing to pay them to .

 

To add, check that the ground connections are clean, tight, and free from corrosion. The engine grounds on these cars is mediocre to say the least.