2012 Infiniti M35h Transmission Lag

[muayad925]

Hey I have a 2012 Infiniti M35h with a lagging transmission, it lags mostly when its in hybrid mode and its trying to down shift and get into a higher gear to speed up,and occasionally it kicks into gear when you give it power. Its really noticeable and its really annoying. I took it to the dealership and they applied all updates and changed the transmission fluid, that helped a little bit but its still there. They said it doesn't seem like theres any internal damage to the transmission.

I dont know what else it can be, they preformed the tsbs. Any one else have this issue or know what it could be?

[Ilya]

Welcome to the forum.

And welcome to the one issue that plagues many of us. My M56 does the same thing sometimes. And other times it runs like a raped ape. No one can figure out what it is.

[muayad925]

Well thats reassuring to know that Im not the only one with this issue, has anyone ever had to replace their transmission due to this issue? Or has it ever became worse?

[Ilya]

Well thats reassuring to know that Im not the only one with this issue, has anyone ever had to replace their transmission due to this issue? Or has it ever became worse?

I'd say negative on both counts. Never heard of a transmission being replaced cause of this and I've had this issue pretty much since I've owned the car so it's been a couple years...hasn't gotten better or worse.

You might want to try resetting your ECU, etc. (there is instructions on how to do that on this sub-forum) and start there.

[ArmedAviator]

My observations on the lagged transmission shifting (downshifting, primarily if not always) seems to be the nature of the automatic beast. Some gears can be changed very quickly, by just pressuring a line to engage a second clutch in a gearset. Others require a clutch of one gearset to disengage while the clutch of another gearset carefully and precisely at the same time. If this isn't done correctly, the clutch pack of one will burn up very rapidly. This is usually where the programmers are careful to not let the end user screw things up so the transmission has it's time to get the job done before commanding more torque again.

The lag really depends what gear your in when you want to get the downshift and how much torque you're commanding (via the accelerator). If you ask for alot, it seems to completely ignore giving you any until a downshift shift has been completed. Again, normal for an automatic with a smart ECU controlling engine torque output to prevent warranty claims from "stupid end users."

[muayad925]

I reset my ECU, and it is running smoother now, but the lag is still there. Its annoying but bearable, really love the car and cant find one that comes close to it so ill deal with it I guess.

[ivntng]

my buddy is having a similar issue with his LS430, but given that it's a much older car he replaced a bunch of components in his transmission but still no luck. he reprogrammed his ECU and it improved but by very little. His next step is that he's going to replace his ECU.. going to cost him about $1100 for the ECU alone.

[Bazza.]

I'm having a similar problem.
from coasting to light acceleration is the worst of it. Feels like it's gonner stall then boom. far too much power or it drops a gear when it's not needed.

As far as I can tell by connecting a OBD tester it's a confusion between the accelerator / throttle sensors and the gearbox. i.e. the accelerator peddle is at 40% before hybrid mode kicks the engine in but the throttle body's are almost closed at 3.5%. Then when the engine kicks in the throttle body's momentarily close before re opening to the requested setting. (lag) At the same time the gearbox reads the accelerator at somewhere between 40-50% and can assume more power is needed, so indeed drops a gear.

This is all guesswork that I haven't really got to the bottom of yet as the Infinti dealers in the UK just keep giving the car back to me as no codes are showing so they cant find anything.

I think the answer is to re calibrate the accelerator position sensors and to somehow stop the throttle lag so that the engine kicks in with the throttle open to the required power rather than closing and opening again. But how to do that is beyond my knowledge.

Or, I'm going a bit nut's........

......Help........

[goat35]

Have you gotten the software update done at the stealership???

This is a recall and I know my dealer danced around it for a while until I had my (inside) guy tell me about it and I requested it.

It took two days but didn't cost me a dime. Call and ask about it.

[Ilya]

Have you gotten the software update done at the stealership???

This is a recall and I know my dealer danced around it for a while until I had my (inside) guy tell me about it and I requested it.

It took two days but didn't cost me a dime. Call and ask about it.

Recall? Only for the hybrid or across the board? Any idea what the 'task' was on your invoice/receipt? This lag is not THAT common but happens often enough where it annoys me. It's totally random. Can go weeks without experiencing it.

[Malbec 56 Beast]

My M does it and so does the G, I think 7 hearts is to many and Infiniti doesn't have the software down. I was giving my son a ride somewhere and I told him how much I hate the hesitation. He said that his friends MB C63 does the same thing. The M has been getting worse lately but as was said above they usually run like raped apes for sure.

I'm getting my trans fluid service on Saturday I'll let you know if it helps.

Andy

[Ilya]

Trans fluid didn't seem to help me. It just makes me drive in manual mode so I control the RPM's and gears...which certainly is more fun.

[goat35]

Have you gotten the software update done at the stealership???

This is a recall and I know my dealer danced around it for a while until I had my (inside) guy tell me about it and I requested it.

It took two days but didn't cost me a dime. Call and ask about it.

Recall? Only for the hybrid or across the board? Any idea what the 'task' was on your invoice/receipt? This lag is not THAT common but happens often enough where it annoys me. It's totally random. Can go weeks without experiencing it.

This is a recall for only the 2012-2015 hybrid.
The timing between the wet/dry clutch pack and transmission causes a shudder and delay sometimes when switching between electric and engine power.

I never got a receipt just a 2 day loaner ex35 sadly

Here's a link to the current recalls for the car

https://www.cars.com/recalls/infiniti-m35h/