09 M35x Limp Mode - 2500 rpm limit [SOLVED - bad battery]

Forum for Infiniti M35 and M45, and Nissan Fuga owners.
mattd860
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Joined: Sat Jun 03, 2017 7:22 am

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I drove my 09 M35x couple hundred city miles yesterday on back roads in Connecticut. Weather was cool and rainy. Near the middle of the trip I filled up at an Exxon gas station (93 Octane) on a busy road but in a not so nice area of a small city that I was in at the time. Continued to drive another 30-40 miles and several hours later when all of a sudden the car went into limp mode without any SES lights or any other warnings. During this time the engine would not rev above 2500 rpms and transmission shifted very erratic and rough. I pulled off into a school parking lot then stopped and restarted the engine several times but nothing changed. I called a tow truck and waited about 30 minutes for it to arrive but as it arrived I decided to start the engine for hahas and to my surprise it was no longer in limp mode and I was able to rev the engine higher than 2500 rpms.

I informed the tow truck driver about all this and he suggested I take it for a spin up and down the street which I did. During this time the car ran perfectly so the driver suggested the car was fine and cancelled the tow.

I then drove 30 more miles to the nearest Infiniti dealership using mostly back roads during rush hour. This took me about an hour. Upon my arrival the dealership ran the codes and looked over the car but all they could find was a low voltage code that may or may not have been related to the incident. So they sent me on my way with a clean bill of health and suggested it was just a fluke. I then drove another 40 miles home without any issues at all.

Could the issue be related to the gas I used? Being that the station was in a very rough neighborhood I wonder if the premium gas I filled up with rarely gets used and may have accumulated moisture. But if the gas was indeed no good would it have taken 40 miles and several hours later to become a problem or would it be more instantaneous? Like I said I drove the car for several hours after filling up and during this time I started and stopped the engine for lunch among other things.

Or was the limp mode a sign of things to come like the dreaded oil seal on the rear timing cover?? If that seal has failed would it cause an intermittent limp mode or would it be permanent?

I’m hoping it’s just bad gas or a fluke but I feel very unsettled about driving the car since I fear that at any moment it will do this again.

Any suggestions?


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Ilya
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Hmm that's an interesting one. I can't say I've ever had gas have that much of an impact on car performance. You could get some pre-detonation and such with certain gas but a full limp mode? Don't know. That's an odd one. You could try running a can of something like Seafoam through the gas tank...

mattd860
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Joined: Sat Jun 03, 2017 7:22 am

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Does the engine in an 09 M35 have the potential for the rear timing cover (oil galley) gasket failure like on the g35s and g37s?

mattd860
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Joined: Sat Jun 03, 2017 7:22 am

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It happened again yesterday and I think I might have figured it out. Once again it went into limp mode where the engine wouldn't rev above 2500rpms and the transmission shifted really erratic and hard BUT, right before it happened I was traveling very slow up a rather steep hill. At the top of the hill was an intersection with a stoplight that doesn't stay green for too long so the traffic was moving slow. Anyways, on the hill I felt the transmission shift a little off and then bam - limp mode. Come to think of it, when it happened earlier in the week I was also on a hill except I was traveling down it.

So my theory is that I'm low on transmission fluid. When I'm on a steep hill the sump goes dry and the ECU and/or TCU realizes this so it forces the car into limp mode to prevent further damage.

When I turn the car off for 15+ minutes the fluid returns to the sump and when I restart the engine everything is good to go.

I'm bringing the car back to the dealer on Monday for a scheduled appointment where they are going to check the transmission fluid level. If the level is fine then I'm at a loss - Although a healthy transmission is never a bad thing :). If the fluid level is low then they I'll have then fill it up but then the even bigger question is why is it low? There are no external leaks.

It's a catch 22. Do I want to find out that my transmission is failing so I can solve the limp mode problem or do I hope the transmission is fine and keep dealing with this mysterious problem?

Question - if the transmission fluid was ever low enough to cause problems, wouldn't it through a SES (CEL) light on the dash?

mattd860
Posts: 39
Joined: Sat Jun 03, 2017 7:22 am

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I was wrong on all accounts. The problem was a bad battery. I brought it back to the dealership to see if they could diagnose the limp mode problem and while they were signing me in and checking the mileage the car literally died in the service area. A swarm of mechanics came crawling out of the woodwork in an attempt to get it started but all failed and ended up pushing the car into the garage area. They replaced the battery and car is now running smooth and strong. I've driven 300+ miles since the battery replacement without any issues. Apparently the old batter was original to the car so it was ten years old.

I also had them check the trans fluid just for hahas and that is obviously fine.

EdBwoy
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Thanks for the update. I would also keep an eye on your charging system, a healthy system should be able to mostly keep the car on if the engine is running.
Check belt, pulley, alternator itself and also the wiring/connections.

FYI, low fluid doesn't typically trigger the CEL or any codes.
Read this link and follow the discussion down a few posts to see what you could experience if your fluid is low - post6791092.html#p6788496


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