dedman

I have a 2015 Q40 - standard 7 speed trans. Just had the speed sensor replaced and the shop that replaced the components reprogrammed the transmission. Since they reprogramed the car shift points seem to be the same as they were before. There is an issue when shifting from 3rd ->4th gear and again when shifting 4th -> 5th. The transmission shifts and the RPMs drop as they should, then there is a uptick in RPM - maybe 3-500 RPM for maybe a second - and a delay in acceleration and then the RPMs drop back to normal and the car carrys on down the road as expected. No clunk or any significant sounds. I believe that there is a clutch between the engine and the trans that is engaging during this time - which is apparently normal operation - but the shift is much different than the shifts prior to the reprogram. (If I switch the car to manual mode there is no delay when I make these shifts by hand, so I don't think that there is a physical issue with the trans or engine - I suspect that it is a tuning issue with the transmission program. Also - if I mash the gas and run through the gears quickly this delay does not occur... Or maybe it is just minimized.)

Just wondering if anyone else has experienced this? I know that there are new/different shift programs released from Infiniti/Nissan from time to time - so maybe there is a fix out there?

I have owned 3 G37s and I can tell you that this definitely doesn't feel normal. Anyone have ideas on how to fix this one?

Diesel_Haphazar

Why did you have the speed sensor replaced? What else was replaced when the shop did the speed sensor?

socketz67

Was the TCM replaced? TCMs get toasted on these cars then throw codes indicating that its the speed sensor.

Diesel_Haphazar

Even if the valve body/TCM was replaced along with the speed sensor, it's plug and play. There's no programming necessary.