2015 INFINITI Q50 Power Train Problems

Transmission valve body failed while driving which caused shifts to be limited. It could have caused an inability to shift at all, which is a safety issue. This issue has been inspected and confirmed by an independent shop. No warning signs were present before the failure. Furthermore, this issue is well known to Infiniti. It’s caused by breakdown of the transmission fluid overtime, causing a reduction in the cooling capacity of the fluid. But Infiniti says that the fluid should be lifetime. This overheating causes the TCM on the valve body to fail. If it failed while I was going at a highway speed I could have been injured.

The car just slowed down super fast on freeway almost got rear ended. It would not go past 3rd gear. Poor acceleration. Could have caused a huge accident. I got it diagnosed and they said it is valve body/speed sensor/tcm and they said this is a COMMON problem for 2015 Q50. I replaced this part 2 years ago and here we go again. Shop diagnosed and said this tcm (transmission control module which is in the transmission) but they have to change whole transmission. Everything happened all the sudden then check engine light came on.

i’m reporting issues with the valve body on a 2015 Q50. I have had to replace the valve body already at cost of $1700. Many others have had same issue as this is a common defect with the TMC part. This needs to be addressed as a recall.

The contact owns a 2015 Infiniti Q50. The contact stated while driving 40 MPH, the accelerator was depressed; however, the vehicle failed to shift into gear properly, with the check engine warning light illuminated. The vehicle was able to be restarted. The vehicle was taken to an independent mechanic, where it was diagnosed that the transmission valve body had failed, and the transmission needed to be replaced. The vehicle was not repaired. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 94,150.

Mileage: 94,150

Just over 1 week ago, I was leaving a parking lot and driving back to my home when my car wouldn't accelerate past about ~10-15 miles per hour and wasn't shifting gears. When I took my foot off the gas pedal, the gear just dropped immediately from above third to first gear and the car shook. I first noticed this when already out of the parking lot and pulling off from a median onto the road, with no engine light or other warnings. I quickly pulled into the turn lane where there wasn't traffic and turned the car off and back on. It was the same but luckily I was in eyes view of my apartment, so I drove under 10 mph and made it home. I took the vehicle to a transmission service center and the error code that came up on the computer was (P0500 - Vehicle Speed Sensor A), which the service center said is an issue with the "valve body" inside the transmission, specifically the "TCM - Transmission Control Module" that sits on top of the valve body. I contacted multiple Infiniti service centers and they all confirmed that the valve body for my vehicle (part# 31705-x133a) is back ordered by over a month and could be longer until they have it. They do not sell the Transmission Control Module separately. The valve body was quoted to me for $2200 for the part alone. I attempted to install an aftermarket valve body and a new error code came up on the computer (PO720 - Output Speed Sensor Circuit). I kept the original valve body and will hold onto it. Doing some more research, this appears to be a common issue with the Infiniti Q50 - [XXX] In addition to the reddit thread above, a quick google search for Infiniti Error codes P0500 and PO720 point to multiple sources indicating the same common experience and outcome. My vehicle has 110k miles and users in the reddit comments are also reporting the same issue with the TCM Transmission Control Module occurring between 85k - 100k miles in all cases. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Transmission intermittently will not shift to the next gear. Sometimes will not shift from first gear, other times will not shift from 3rd gear. Sometimes no issue at all. It is intermittent and no warning to when the issue might happened. It happens when trying to accelerate and has put me in an unsafe situation trying to accelerate on the highway or around town.

Air bag light suddenly said “passenger airbag off”. Don’t have to brake to switch gears. Steering at times feels a bit off.

Transmission failure without warning!!

Transmission, Transmission Valve body, speed sensors. After transmission shifting issues while traveling the interstate I had to have the car towed to the dealership. After the multi point inspection was performed serveral recommended itmes related to the ongoing performance and SAFETY of the vehicle listed below: Transmission $10,446.65 Transmission Valve Body $3693.92 The diagnostic code P0720. Attached is the service bulleting stating they know this will happen and when it does here's how to fix it. Yet they have never recalled the defective transmission. When I contact Infiniti consumer affairs they simply say that they cannot help me because the vehicle does not have warranty. If i had warranty then I would not be reaching out to them for assistance in replacing the transmission.

While driving on the interstate and coming over an overpass there was unavoidable debris located in the road. Immediately after passing over the debris there was a loud noise followed by jerking and the RPM's revved up almost like the car was in neutral. I let up off of the accelerator and then tried to accelerate again. The car would not go faster than 30mph and will not shift out of 3rd gear. I had the car towed to the dealership and the diagnostic codes reflected vehicle speed sensor and there was no physical damage that was visible under the car. I was told that the problem was in the transmission and that it would need to be changed and given an estimate that totaled over $10,000. I was also told by the service advisor that this is a known issue with the Infiniti Q50. After doing researching this a common problem and the consumer is having to pay out of pocket if the warranty has ended. This incident could have ended badly while doing 70mph on the interstate and the car just quits moving. With all of the complaints that I have read over in regards to the transmission issues yet no action has been taken to investigate this problem. It is obliviously a manufacturing issue and the consumer should not have to pay out of pocket for defective transmissions. This luxury car was not a cheap purchase. Very disappointed that with so many cases an investigation has never been done. Infiniti should be held accountable and a recall should be issued for this problem. I will not stop until I can get through to someone that can help.

Valve body goes bad after a few hundred miles every time. fluid enters the tcm causing it to go bad. the tcm could be welded back on but dealer just replaces the whole transmission

I received a recall notice (folded information card) from Infinity in the mail in about August 2024 regarding Recall NHTSA 24V-470-R24A7. I also received an email from Infinity on August 28, 2024 with Subject "Your Q50 is due for Important recall repairs " and noted it stated Recall Code R24A7/R24A5: NHTSA 24V-470: Recall Description Q50/Q70 Prop Shaft. I contacted Infinity to schedule the repair and received a confirmed email service appointment for October 4th 2024. When I arrived at the dealership the service department told me they did not have parts but would change my oil and do other service for a fee. All I wanted was the recall fixed. In total I've been to the dealer 3 times and been always told that they have not received parts from the manufacturer. Today I called Infinity Consumer Affairs Department at 1-800-662-6200 and spoke to "Dennis". He did little but talk in circles and did nothing to provide information and when the recall would be fixed. Since I was getting no information and he was not listening or helping I told him I was ending the call and calling the NHTSA, which I did and spoke with Tyronda. Confirmation number for call she gave me is [XXX] for our call. After my repeated efforts and complaints, Infinity appears to have no interest on fixing the vehicle recall they first advised me of in August, only seemingly "going through the motions" as slow as possible. My car is not fixed after about 4 months and they have done nothing to contact me as to when it will be repaired. That is my complaint INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Transmission valve body failed and is a common problem for 2014-2016 I was on a busy road and the car threw check engine light and wouldn’t accelerate any more. I risked my safety and others because I was stopped in the middle of the road and lots of commuters passing by and the vehicle was fully registered and inspected by the state prior that happened but it’s a common problem that you’ll never know when it will fail.

Valve body went out with 89k miles and had to get transmission replaced.

The valve body/TCM shorts out on the car unexpectedly and can happen at any time causing the car to be unable to go past third gear. This is an known problem with 2014-17 Infiniti Q50 & there is a service bulletin issued by Infiniti associated with this problem published in November 2019. This vehicle was inspected by Infiniti dealership and they confirmed the issue. There was no warning light or prior to this event. After the failure this codes popped up P0720. Repair was ~$3500

The contact owns a 2015 Infiniti Q50. The contact stated that while driving at an undisclosed speed, the vehicle stalled. The contact was able to drive the vehicle off the highway and park the vehicle. The contact stated that the failure occurred while the contact was driving on a busy highway. The vehicle was towed to the dealer where it was diagnosed with transmission valve body failure. The contact was informed that the transmission valve body needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 74,000.

Mileage: 74,000

My engine light came on at 115,946 miles causing my vehicle not to accelerate or shift properly which could have resulted in a accident. The vehicle was diagnosed at local Nissan dealership with code P0720 and P0500 stating vehicle need a transmission. Prior to this diagnose this vehicle was diagnose twice by a Nissan and Infiniti dealership concerning the shifting and acceleration issues but could not duplicate the issue at the time. I see where numerous car buyers are stating they’re having the same issues with the Infiniti brand at low miles and high miles.

My car would not accelerate over 40 mph randomly after work. Once i noticed and tried to shift to a lower gear the car did not shift gears at all. When these things first happened there was no indicator lights on. The next morning the check engine light came on and the code pulled was P0720. After finding a repair shop to look further into the issue I was advised the car needed a new transmission to fix the issue. $4,000+ for the repair and as i google the issue I see that this is a common issue and it seems to always happen unexpectedly side note: also should be a recall on driver side blend door.. i almost died this summer due to cold air only blowing on one side in the middle of summer in 100• degree weather.

$2000+ to fix but not recalled for Yet Way too more than thousand Infiniti Owners has had the same issue with Valve Body Code:P0720

The contact owns a 2015 Infiniti Q50. The contact stated that while driving approximately 50 MPH, the vehicle began to overheat and smoke was present coming from under the hood. After stopping to inspect the vehicle the contact opened the hood and flames were present in the engine compartment. The contact immediately extinguished the flames using water. The vehicle was later towed to the local dealer. The cause of the failure was not yet determined. The contact indicated that prior to the fire the vehicle had also experienced transmission shifting failures and the front driver's side and passenger side seat belts were locked in the retracted position and could not be used. The cause of the failures was not determined. The manufacturer was not notified of the failures. The failure mileage was 80,000.

Mileage: 80,000

My car has 60,000 miles on it and multiple mechanics as well as the Infiniti dealership tell me it needs a new transmission. $8,000. It will not shift above 2nd gear. I took the valve body and manifold out of the transmission and was surprised to find that the output speed sensor plug is actually a dumby plug that connects to nothing. I've had cars with hundreds of thousands of miles on them still driving with the same transmission they were born with. I've rebuilt a lot of engines, but never had to replace a transmission, especially not after 60,000 miles. Any, I searched the internet and noticed that it's a very common problem with this vehicle.

The speed sensor on car seems to have failed unexpectedly while driving over a bridge. The car would barely move and could have become a dangerous situation for multiple people had it been typical traffic. The issue seems to be that although the sensors are corrupted, the entire valve body or transmission must be replaced to solve the issue leaving the car inoperable. The car is currently at a repair shop. The engine light did come on shortly after. PLEASE ISSUE RECALL. https://static.nhtsa.gov/odi/tsbs/2019/MC-10168892-0001.pdf

I was driving perfectly fine and i stopped at a red-light. I went to accelerate and the car wouldn't shift out of first gear and then check engine light came on. I pulled over and scanned the codes, it showed code p0500. After bringing to shop and reading thousands of different things from people who own the car online all said the same thing. Transmission valve body is shot. I almost got rear ended when i let off the gas because the engines rpms were so high casuing quick engine braking.

The car was being driven on a normal day and while in gear and driven the car stalled and would no longer shift automatic. The car will not come out of 3rd gear. Took the car to repair shop and was told is a known issue with this model and even the transmission or transmission valve body needs replacement. Infinite will not issue recall and I have reach out to corporate on the issue the repair want 8,000 to replace transmission the car is out of extended warranty that was purchase on the vehicle I’m only the second owner of the car well maintained and should not be having this issue of a self maintained transmission with a vehicle worth 25,000 wen brought.

The valve body/TCM. Yes the vehicle is available for inspection. The valve body/TCM shorts out on the car unexpectedly and can happen at any time causing the car to be unable to go pass third gear. This can occur on the freeway, or when trying to avoid an accident. This is an known problem with Infiniti’s & there is also an service bulletin associated with this problem. This vehicle has be inspected by the dealership and they confirmed the issue. There are no warning light or and thing prior to this event. After the failure this codes popped up P0720 & P0500. This occurred on Aug 13, 2022

The vehicle would not shift above 3rd gear. I was driving down interstate and got off the exit and the shifting acted up. We were able to get home but this is clearly an issue that NHTSA has identified and this should be a recall. I have copied the link below. https://static.nhtsa.gov/odi/tsbs/2019/MC-10168892-0001.pdf

Valve body completely went out. This happens on most Infiniti’s per my transmissions specialist I took it to. He suggested I contact you.

My Car Suddenly Stopped In The Middle Of The Road With A Check Engine Light. I Have a P0720 & P0500 Codes Indicating A Vehicle Speed Sensor & Output Speed Sensor Failed While Operating . This Cause My Transmission To Fail And Not Shifting. I Am On My Way To The Dealer Now . Hopefully Infiniti Will Do The Right Thing And Fix It . At 56,000 Miles A Transmission Should Not Fail . Unexpectedly Almost Causing A Car Collision . No Prior Warning Was Provided By The Car . The Car Just Suddenly Failed . This Is A Very Serious Safety Concern .

While driving my Q50 on the highway at around 65mph my car automatically down shifted to 1st gear. It was a really hard shift, so hard I thought someone rear ended me. To down shift that quickly on the highway placed me in a very unsafe position. My car almost came to a complete stop without any notice to the vehicle behind me. Someone could have rear ended because I didn't hit my breaks. Thank God the car behind me was pretty far back, because if they had been a little closer, they would have hit me.

I WAS DRIVING MY INFINITI Q50 and puled up to a light. When it turned green I proceeded when I noticed my check engine light comes. It won't shift past 3rd gear. it seems to be in limp mode but there was a tractor trailer barreling down on me. So I get to 35 MPH and ride the side of the road. Once I got home I did a search and apparently there are A LOT of issues with this transmission. Most indicated it was the valvebody and that it could cost upward of $2,500.00 plus there is a back order on them. This is my only car and can't have it tied up to long. I have an appointment to have it diagnosed this coming Wednesday, 06/09/2021. I can't drive it or I will burn up the transmission. If there is such a large problem I would think this would have a recall on it. My car only has 65, 624 miles on the clock. This needs to be addressed. I am hoping for a miracle when it gets diagnosed but with all the evidence out there about the bad transmission in these cars I am expecting the worse.

On 5-25-2021 while merging into traffic on busy I-75. My 2015 Infiniti Q50 did not change into a higher gear as it should have causing the vehicle to not accelerate and lose power then the check engine light came on a few seconds after failure.This failure of the vehicles drive train placed my wife’s life and my life in extreme danger in which we were not able to accelerate with the flow of traffic and was nearly ran over by several semi tractor trucks. The vehicle is in the repair shop for the transmission valve body failure and replacement. I’ve looked this issue up online where numerous owners of this type vehicle have complained and described this as a common problem with these vehicles.

MY CAR PAUSE AND JERKS THEN STOPS. THIS IS THE SECOND TIME THIS HAS HAPPENED AFTER BEING FIXED. THE MECHANIC SAID THEY HAD A RECALL ON THE 2016 MODELS FOR THIS BUT NOT THE 2015 BUT HAD TO CORRECT MANY OF THE 2015 MODELS. THE CHECK ENGINE LIGHT CAME ON AFTER IT STOPPED. I WAS ON THE INTERSTATE THE LAST TIME WHEN IT STOPPED. I AM AFRAID THAT IT MIGHT HAPPEN AGAIN WITHOUT ANY WARNING. THIS IS A LIFE THREATENING DEFECT THAT INFINITI NEEDS TO CORRECT ASAP.

TL* THE CONTACT OWNS A 2015 INFINITI Q50. THE CONTACT STATED WHILE DRIVING APPROXIMATELY 70 MPH, THE VEHICLE JERKED, SHIFTED GEARS, REDUCED SPEED, THE ODOMETER FLASHED, THE CHECK ENGINE WARNING LIGHT ILLUMINATED, AND THE HEATING AND AIR CONDITIONING SYSTEM WENT FROM COLD TO HOT. THE CONTACT GOT OFF THE NEAREST EXIT AND PULLED OVER AND WAITED A WHILE BEFORE CONTINUING TO DRIVE HOME TO PARK THE VEHICLE. THE CONTACT STATED THAT A DIAGNOSTIC CODE READER RETRIEVED DTC CODE: P0720 (OUTPUT SPEED SENSOR). THE CONTACT CONTACTED INFINITI OF TAMPA (4600 N DALE MABRY HWY, TAMPA, FL 33614; (813) 694-1579) AND WAS INFORMED THAT THE CAMSHAFT NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT MADE AWARE OF THE ISSUE. THE APPROXIMATE FAILURE MILEAGE WAS 65,000.

Mileage: 65,000