2015 Infiniti Q50

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.

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)

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.

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.

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

4/16/2023 Sunday 5pm With my wife and daughter in the car, I started the vehicle in my driveway and selected Sport mode as usual. Selected reverse and backed into our turnaround then forward to the end of our driveway. Driveway is approximately 4 car lengths long with a 20 ft long apron turnaround. Almost immediately after braking at the end of the driveway while waiting for passing traffic to exit drive, vehicle suddenly accelerated and I immediately pressed the brake as hard as I could to prevent driving into passing vehicles. I could hear the tires trying to grip/spin while I was fighting to press the brake harder to hold it t back. I then panicked and selected the gear shifter to anything other than drive and it immediately did the same in reverse. After getting in into park, I immediately selected Standard mode and the vehicle performed normal afterwards. There were no warning lights or anything to indicate any issues. Previously I had noticed minor intermittent issues of high RPMs when slowing or braking while in Sport mode but it would immediately correct itself. I have not had a chance to take it for inspection as it's now Monday morning April 17. We were all very shaken. Please advise.

My vehicle suddenly jumped then accelerated slowly and wouldn't get past 3rd gear while driving on I275 (speed limit 55MPH) proceeded to mechanic, error code 0720 speed sensor output related to transmission. Then was told by Infiniti and another auto body repair shop that it most likely in models 2014-2016 it was a transmission assembly that needed replaced. that Infiniti was given a service bulletin that they should not just replace the speed sensor. I believe this should be a recall. My vehicle has less than 60,000 miles and has been garaged and has had all maintenance completed. This is a safety issue, Infiniti is aware of this and it is also a costly repair anywhere from $2500-$3000. I am asking for a recall of Valve body for Infinite Q50 2014-2016.

WAS DRIVING MY INFINITI Q50 ON A NORMAL DRY DAY WHEN ALL OF A SUDDEN IT DOWN SHIFTED OR FELT LIKE I WAS DRIVING A STANDARD MODEL VS AUTOMATIC... I PULL OVER MY ENGINE LIGHT COMES ON.. I TURNED OFF ALL SENSORS ASSOCIATED WITH THE INTELLITOUCH SYSTEM THINKING IT WAS NOT JUDGING THE DISTANCE CORRECTLY BETWEEN CARS BECAUSE IT WILL AUTOMATICALLY SLOW YOUR CAR DOWN... CONTINUED DRIVING AND I'M NOTICING AS I TRY TO ACCELERATE MY CAR IS NOT SHIFTING INTO 3RD GEAR... SO I GET TO ABOUT 35-40 MPH AND NOW I CAN TELL IT'S REVVING IN THE SAME GEAR..GET HOME GOOGLE THE ISSUE AND IT SEEMS THE VALVE BODY ON THE 2015 Q50 HAS A THREAD... GO TO YOUTUBE THIS GUY HAS A VIDEO ABOUT HIM BEING TOLD IT'S THE SPEED SENSORS... BUT WHEN HE WENT FOR REPAIR INFINITI INFORMS HIM THE VALVE BODY NEEDS REPLACING. I TOOK MY CAR INTO AN INFINITI DEALER , SPENT $180 TO HAVE A DIAGNOSTIC RUN AND WAS TOLD THEIR IS A SERVICE BULLETIN FOR THE SPEED SENSORS THAT THEY SHOULD JUST REPLACE THE VALVE BODY. THE VALVE BODY IS $1635 AND ON A NATIONAL BACK ORDER AS OF AUGUST 2020 WHEN I'M EXPERIENCING THIS ISSUE.. CALLED INFINITI CONSUMER AFFAIRS AND I'M TOLD WELL UNLESS YOU PAY FOR THE PART WE CAN'T DO ANYTHING TO GET IT EXPEDITED... IT'S BEEN 45 DAYS... SO I HAVE TO TIE UP $1700 AND DON'T KNOW WHEN THIS PART MAY BE AVAILABLE.. CAN'T DRIVE CAR BECAUSE I'LL BURN MY TRANSMISSION UP... THE VALVE BODY IN 2015 Q50'S NEED TO BE RECALLED...I COULD HAVE BEEN ON THE FREEWAY OR DRIVING TO OR FROM LOUISIANA FROM HOUSTON.. LUCKILY I WAS WITHIN 15 MILES OF MY HOME.. CALLED THE OTHER 2 INFINITI DEALERS IN HOUSTON NONE OF THEM HAVE IT IN STOCK AND HAVE AT LEAST 1 Q50 WAITING FOR REPAIR.. CALLED THE DEALER IN AUSTIN ALSO NO STOCK WITH 2 VALVE BODIES ON RESERVE... I HAVE 106000 MILES ON MY Q50 AND IT'S NO LONGER UNDER WARRANTY.. THIS ISSUE HAS BEEN REPORTED AT FEWER MILES LIKE 30K-50K SO HAS NOTHING TO DO WITH THE AGE OF THE CAR.