59 of the
740 complaints filed about the Infiniti Q50
are about the other systems —
8% of everything owners reported.
The worst model year for it is 2015.
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 complaint #11756528 — an unverified report by a vehicle owner.
The serpentine belt on my 2018 Infiniti Q50 Sport became contaminated with oil immediately after dealer turbo replacement at the end of August 2025, causing the belt to slip, shred, and be pulled into the engine. This resulted in sudden loss of essential engine functions and poses a significant safety hazard. This failure was caused by improper repair at the dealership.”
NHTSA complaint #11701863 — an unverified report by a vehicle owner.
My vehicle has been stalling and burning/leaking oil internally for some time now with white smoke coming from the rear. Well Infiniti sent a post card and stated that the emission warranty is extended for 120,000 miles which my vehicle has had the issue for some time and it was already over 120k miles at the time of the loss. The issue Infiniti reported in their postcard is, you may experience issue with the turbocharger, Overtime there is a possibility for the turbocharger thrust bearing to wear and leak oil internally. The most likely conditions you will experience are excessive white smoke from the exhaust, MIL-On an in rare cases reduced engine power or damage to the internal components. My vehicle is experiencing all these issues reported and the company, Infiniti, knows this is an issue and did not issue a recall the extended warranty instead, most people will not qualify for which will require people to thousand of dollars replacing the turbocharger assembly and engine control model. I got a quote and was told 8000 dollars unfortunately I cannot have repairs done. I believe it was January 2025 when the post card came from Infiniti identifying the issue
NHTSA complaint #11700285 — an unverified report by a vehicle owner.
Car is showing a p0720 code which is an issue with the valve body. The car will not go past 3rd gear. This is a known problem with this vehicle. Infiniti is not issuing a recall. The car won't run and the consumer is having to foot the bill for the repair when they know it's an issue with the vehicle and the transmission.
NHTSA complaint #11696543 — an unverified report by a vehicle owner.
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 complaint #11664950 — an unverified report by a vehicle owner.
I was driving down the highway leaving the barbershop and my car wouldnt go over more than like 55 mph and I got a flashing green symbol beside my check engine light which had just came on when the AUTO (Stop/Start) light did. once I got home turned it off and turned it back on the for a second the light doesn’t come on but once you drive it maybe a quarter of a mile or less it come back on and the car wont function properly again
NHTSA complaint #11663542 — an unverified report by a vehicle owner.
Driver has noticed ignition delay. Cause is unknown. Tire change is due. Cause is regular wear and tear. Vehicle inspection can be scheduled. Delay places safety of passenger at risk. Unknown if problem has been reproduced or confirmed by a dealer or independent service center. Tires were inspected by Discount Tire on November 26, 2024. Place key close to ignition message is frequently displayed on dashboard.
NHTSA complaint #11628183 — an unverified report by a vehicle owner.
The locks on the car automatically keep locking all day long and drain my battery, I have had to have my car jump started and recently towed to Infiniti dealer and they are stating there have been known issues with this electrical problem with rain getting into the sunroof and deteriorating the lines that short out the other systems. I have a bumper to bumper warranty that I took out with the Infiniti Dealership but they are stating only part of the repairs will be covered by the warranty and not the sunroof part and that will cost me $1,300 to fix. If this is a known problem, how is this not a recall and why do me, the consumer, have to pay out-of- pocket for something that is a known issue with the sunroofs on these Infiniti's? Can someone please contact me regarding this issue asap. It started when my car was at Infiniti's body shop in September getting repaired from a hit and run to my vehicle that required replacement of rear left back panel and rear left back passenger driver door (that had nothing to do with this issue) and when I picked the vehicle up they had to jump start my car. They had my car for a month and nothing prior to this was wrong with my vehicle. I don't know if someone left my sunroof open and it rained or what happened since this repair, but now I am having the issue with the car locks automatically/continuously locking and draining my battery. I read online that there is a button that should be available on the dashboard to shut off the automatic locking system, but the dealer has not mentioned this and is stating I need all this electrical things done to my car that will cost over $3,000 and that the sunroof part is not covered. This is absurd and not trusting what I am hearing from the dealership. Please advise asap. Thank you for your time!
NHTSA complaint #11621012 — an unverified report by a vehicle owner.
Power steering failed while driving in parking lot looking for parking spot. Unable to turn wheel without hitting parked car. I was able to drive to end of the lot where there were less cars. Noticed that I was able to turn wheel so long as didn’t step on brakes. The steering wheel was also off alignment. This happed on a Saturday evening, next day car was fine all the warning were off. Spoke to service person explained what happened. He basically said if the car is running fine they can check it out but may not find the problem. Since the car was running fine until it wasn’t. Car was parked in garage turned on the car all warning lights go on. Made appointment for 4/3/24 drove car to dealership which is not to far. The warning lights still on and no power steering. Analysis many DTC codes found related to this system:B2512 4WAS SIG: C1B9000 DAST SYSTEM: C1138 4WAS CIRCUIT & C1A04 ABS/TCS/VDC CIRC. Correction Recommended to perform DAST calibration first before performing further diagnosis. COST $539.15 . They also did Multi-Point Inspection items requiring immediate attention Engine Air Filter COST $94.99 GRAND TOTAL $641.64 out of pocket. 4/3/24 picked up car. On that evening drove the car and as I’m pulling up on drive way power steering goes out again. I managed to get the car in garage. Once I’m in push button to close garage doesn’t work and car dies no power at all. Able to get car started by playing with battery cables. On dealership notes car was there 30 miles ago. Now they say wrong battery size. That battery was replaced by them on 2/28/22. Also the battery just past Multi-Point 2 days ago.New battery cost $232.78 now out of pocket $874.42.This is now 4/10/24. Drove that evening and front splash guard fall off had to tie wrap to hold whatever pieces are left. Took it to dealership they took no responsibility. I will need to replace it. I have all my receipts from them they are the only ones who have worked on my vehicle.
NHTSA complaint #11583692 — an unverified report by a vehicle owner.
I was in my car waiting my for complex security gate to open when I heard a loud noise. I got out of my car to see what it was and turns out my sunroof exploded. For no reason. No rock or item hit my car nor was the car in motion. It was also not from the heat as it was 60 degrees outside. I called my warranty and they refuse to cover it because it is glass. I am reading many others with this same issue. How does a 6 year old car have the sunroof explode??
NHTSA complaint #11573206 — an unverified report by a vehicle owner.
My car started acting weird, fob wasn’t working correctly, doors repeatedly lock nonstop and drained battery. I took to Infiniti and they said it’s water damage from my sunroof drains. It damaged my BCM. Infiniti has quoted me 3,700 dollars to fix. I’ve done lots of research and this seems to be a very common problem with the Infiniti q50 models. I believe this is a manufactured defect. This could of left me stranded because car wouldn’t crank.
NHTSA complaint #11573027 — an unverified report by a vehicle owner.
My vehicle was stolen by theives using some kind of device to gain access because I have both key fobs that came with the vehicle but somehow they were able to gain access and start it and drive off. I believe this is a security and safety concern for Infiniti vehicles. it should not be easy to steal a locked, secured vehicle.
NHTSA complaint #11568300 — an unverified report by a vehicle owner.
Unknown- Vehicle left the highway and crashed into a tree in a ravine and then was fully engulfed in flames. Both occupants were DOA after the fire was put out.
NHTSA complaint #11564456 — an unverified report by a vehicle owner.
Sun roof drain is clogged which has caused my carpets to go wet literally puddles, could potentially damage my electronics in car this is an ongoing problem for thousands of Infinitis. I am in a group on Facebook and I can literally scroll and find hundreds of Infiniti owners complaining about their carpets and how Infiniti dealerships charging thousands of dollars to repair. I’ve been holding off to get this fixed in hopes that I’d find someone to assist me with a lower price but nothing
NHTSA complaint #11555335 — an unverified report by a vehicle owner.