2015 INFINITI Q50 Owner Complaints

While operating the vehicle, the transmission suffered an abrupt failure resulting in Diagnostic Trouble Code (DTC) P0720 (Output Speed Sensor Circuit). Further diagnostic inspection revealed a complete internal failure of the integrated valve body assembly, which houses the Transmission Control Module (TCM), solenoids, and output speed sensors. The failure caused an immediate loss of gear selection, restricting the transmission to 3rd gear ("limp mode"). Attempting to accelerate beyond 3rd gear causes violent vehicle shaking, severe hesitation, and an inability to maintain traffic speeds due to the TCM losing signal input from the speed sensors and solenoid circuits. This total valve body/TCM failure creates a critical safety hazard. Sudden restriction to 3rd gear without warning on highways or during turn movements leaves the vehicle unable to match surrounding traffic speeds, creating an immediate risk of a rear-end or side-impact collision. The vehicle has been strictly maintained according to manufacturer schedules. Because Nissan/Infiniti designed the TCM and speed sensors as an integrated unit inside the hydraulic valve body, a sensor failure requires replacing the entire valve body/TCM unit—a repair quoted at over $3,000, with complete transmission replacement exceeding that cost. This valve body/TCM failure mode is widely documented among Infiniti Q50 owners sharing the RE7R01A 7-speed automatic transmission platform, indicating a widespread electronic and mechanical defect that threatens driver safety.

NHTSA ID

11756528

Incident

Aug 8, 2026

After starting the car the steering wheel jumps off center and the steering is all over the place. have to start the car again and the steering wheel jumps the other direction. I strongly suggest this is exactly what the June 13, 2016 NHTSA campaign number 16V43000 the software may reduce steering ability and increase risk of crash.the direct steering system my experience an error at vehicle start up altering the vehicle steering responsiveness and turning radius. Exact problem with this car. This car has been recalled for the driveshaft break NHSTA 24V470000

NHTSA ID

11753148

Incident

Jun 2, 2026

DIRECT ADAPTIVE STEERING EXPERIENCEING AT START UP ALTERING THE VEHICLES STEERING AND RESPONSIVENESS AND TURNING RADIUS DOES NOT WORK AND IS INCREASING THE RISK OF A CRASH. VERY UNSAFE TO DRIVE. THERE IS A RECALL 16V430000 ON THIS VERY PROBLEM. HAVE BEEN TOLD BY DEALERSHIP AND NISSAN MOTORS THAT MY CAR IS NOT ON THE RECALL AND I WILL HAVE TO PAY MY SELF TO GET FIXED AND TO SEE IF THAT IS THE PROBLEM. READING THE NHTSA CAMPAIGN NUMBER:16V430000 THIS IS THE EXACT PROBLEM WITH THE DIRECT ADAPTIVE STEERING SYSTEM ON THIS CAR. I BELIEVE THIS SHOULD BE COVERED BY THE RECALL!

NHTSA ID

11751944

Incident

Jul 21, 2026

While driving my 2015 Infiniti Q50s, the transmission suddenly suffered a catastrophic electronic failure, causing the vehicle to immediately drop into "limp mode." This resulted in a sudden and dangerous loss of acceleration while operating in traffic. A diagnostic scan revealed trouble codes P0500 and P0720 (Output Speed Sensor circuit). However, following Infiniti's official Technical Service Bulletin (TSB ITB19-040), the actual failure was the Transmission Control Module (TCM), which is permanently integrated into the transmission control valve body inside the transmission. Because the speed sensor cannot be replaced independently of the integrated module, I was forced to pay out-of-pocket to replace the entire transmission control valve body assembly and have a dealership program the new unit. This is a widely documented, premature failure on this vehicle platform that creates an immediate highway safety hazard when the vehicle drops power without warning.

NHTSA ID

11750490

Incident

Jul 7, 2026

DAS issue that I have been dealing with for two months now, issue is still not resolved even after taking out a personal loan for 6k to fix the modules at Douglas Infiniti, waited weeks for the modules, they replaced the modules, did the calibration but a new issue is happening where I'm losing control for a split second and the car would either pull to the left or right egregiously. I took it to back to Douglas Infiniti for the issue, they found code C13E9-00, cleared the code and did the calibration again only for the issue to happen again once I was close to getting home. Spoke with Martin the advisor and he is saying that he thinks its an issue with the rack and pinion and not a software issue. I bought the rack and pinion from infiniti's wholesale direct website, the rack and pinion came from Infiniti of Winston Salem, so it's an OEM rack and pinion, he said I should take it back to the shop where I got it installed and have them check their work, even though they were able to calibrate the system once the new modules were installed, certify their work and give me back to the keys to the car only for the issue to happen again. Took it back to DriveWorks Auto Center in Union, NJ and they couldn't find any issue with the rack & pinion, said I need a wheel alignment thought, went and got a wheel alignment. Driving home from work yesterday on [XXX] going down the hill and the car steering went out momentarily and the car started pulling to the right, straightened the wheel and now I was swaying to the right. I have a case open with Infiniti Consumer Affairs INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11745913

Incident

Apr 1, 2026

The valve body on these cars are useless. Driving down a highway and cant shift out of 3rd gear almost had a car re-end me. Today I am driving and the ECU is not responding I see the check engine light on then I'm like not again. This would be the 3rd valve body I replaced. First I replaced the whole transmission thinking that is what I needed and advised that the valve body and the transmission are one. Yet no they come in parts. Anyways today I am waiting to get home, but the car is not reading my key fob why? Then the ECU and code U0100 is popping up. Something new and turns the car off. The shifting that happen earlier was just a light bulb of I already knew what is wrong. I felt the car shift with a hunch so I looked at my dash board and saw the check engine light again and was like not again. Please not again. Now on the dash board I see AWD and chassis issue. Then online I am told electrical problem and or ECU module not reading correctly. Like what is up with these push to starts. They are becoming a headache. I need to know just why I am replacing my valve body now for the 4th time???? This all can cause an accident that my car randomly slows down.

NHTSA ID

11737881

Incident

May 14, 2026

The transmission speed sensor has failed needs a new valve body. It seems like a very common problem with this car and it’s a $3000 fix according to my mechanic. I think there needs to be a recall issued considering everybody on this website is reporting the same problems.

NHTSA ID

11731441

Incident

Apr 14, 2026

The contact owns a 2015 Infiniti Q50. While driving at various speeds, the transmission was slow to shift. The vehicle failed to properly accelerate while depressing the accelerator pedal, and the check engine warning light remained illuminated. The vehicle was taken to a local transmission mechanic to be diagnosed, and it was determined that the gear ratio and speed sensor inside the transmission valve body were faulty, and that the valve body needed to be replaced. The valve body was replaced, and the failure was repaired; however, one week later, the failure reoccurred. The vehicle was taken back to the mechanic, and it was informed that the transmission needed to be replaced. The vehicle was not yet repaired. The manufacturer and local dealer were not contacted. The failure mileage was 99,000.

NHTSA ID

11722204

Incident

Oct 1, 2023

Mileage

99,000 mi

Transmission Control Body. Lost of speed during driving which put me in danger of being hit from behind on the highway. The car was scanned and came up the code P0500 and P0720.

NHTSA ID

11718621

Incident

Feb 12, 2026

The door lock of the driver's door is stuck in the locked position and the door cannot be unlocked or opened. It will not unlock using the key fob, nor with the manual control inside the door, nor with the emergency key from outside the car. This could trap an inured driver inside the car in the event of an accident. The car has not yet been inspected by anyone. There was no warning lamps or messages prior to the failure. Earlier that same day the door failed to open while in gear but did so when I shifted to park. As this car was very recently purchased by me and I am still learning about it, I failed to recognize this a symptom of an impending failure. Regardless of that warning, total failure occurred the same day. As a graduate engineer who has worked in engineering related fields for more then 50 years I can recognize that a failure mode such as this is both a health and safety hazard to occupants in the event of an accident and a design defect that should not be allowed to be sold to the general public. Thank you for any consideration you give this complaint.

NHTSA ID

11703560

Incident

Dec 5, 2025

Was making a left turn when the steering stopped working and the motor lost power, the adaptive steering quit working after approximately 15 mins. I started the car and it was working. Went a half mile made a right turn and it went out again. Shut off the motor tried to start it and could not. 20 mins later it started and has been working since. Dealer couldn't find the problem and wouldn't fix it, they also said that their were no recalls but I know that is not true. Infiniti had a law suit brought against them for the adaptive steering issue. If they fixed it why doesn't it work right.

NHTSA ID

11689862

Incident

Sep 10, 2025

Unknown. Started to make left turn steering made loud banging noise then lost all power. Stepped on gas pedal would not go lost steering control and coasted to a stop. Adaptive steering went out. Almost got hit by on coming traffic.

NHTSA ID

11686782

Incident

Sep 10, 2025

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.

NHTSA ID

11684079

Incident

Aug 16, 2025

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.

NHTSA ID

11683201

Incident

Aug 24, 2025

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.

NHTSA ID

11681660

Incident

May 1, 2025

P07200 code came up, transmission is no good because of a cheap sensor that's impossible to fix. seems to be very common and very inconvenient

NHTSA ID

11681641

Incident

Jan 23, 2025

Adaptive steering clicks and looses control. Steering wheel jerks back when self aligning. There was a recall for this I believe in June 2016. For 2015 infinity Q50’s but my VIN says that it wasn’t recalled but is the exact description of what is happening.

NHTSA ID

11674949

Incident

Jul 20, 2025

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.

NHTSA ID

11672262

Incident

Jul 9, 2025

Mileage

94,150 mi

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)

NHTSA ID

11664950

Incident

May 26, 2025

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.

NHTSA ID

11663166

Incident

May 22, 2025

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

NHTSA ID

11655792

Incident

Apr 21, 2025

Transmission failure without warning!!

NHTSA ID

11655236

Incident

Mar 14, 2025

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.

NHTSA ID

11649578

Incident

Mar 20, 2025

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.

NHTSA ID

11649291

Incident

Mar 7, 2025

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

NHTSA ID

11647122

Incident

Aug 11, 2015