Infiniti Q50 check engine light comes on

Filed Sep 21, 2026 · Acceleration, Engine · GA

In August 2026, while driving, the vehicle suddenly lost acceleration and engine power and would only travel at a very slow speed. The check engine light came on. The driver had to safely stop, turn the engine off, and restart it. After restarting, the vehicle temporarily regained acceleration and normal speed. This problem has occurred more than once and creates a serious safety risk in traffic, especially when merging or crossing intersections. An INFINITI dealer inspected the vehicle and advised that the problem may involve the turbocharger system, with repairs estimated at approximately $4,000. INFINITI Consumer Affairs was contacted about the loss of acceleration but declined financial assistance because of the vehicle's mileage/warranty status. The vehicle was previously an Enterprise rental vehicle and had prior INFINITI service history. The vehicle is available for inspection. I am requesting investigation of this sudden loss-of-power condition.I am aware that the federal safety agency Recall 21V‑234 / INFINITI Campaign R20C5 involved certain 2021 Q50 vehicles and an ECM software condition associated with a warning light, reduced power, and possible engine stall while driving. My VIN currently shows 0 unrepaired recalls, but I am requesting verification of whether this campaign ever applied to my vehicle and, if so, when and at what mileage the ECM reprogramming was completed. My vehicle is now experiencing a Check Engine Light and sudden loss of acceleration/power while driving, which temporarily improves after the engine is shut off and restarted. I am also aware of INFINITI TSB ITB22-038D/EM22-007D concerning turbocharger replacement procedures for 2016–2024 Q50 vehicles equipped with the VR30DDTT engine. I request investigation of whether my present loss-of-power condition is related to the ECM, turbocharger/boost system, or another safety-related defect.

Filed Sep 8, 2026 · Engine · 82,000 miles · GA

The contact owns a 2021 Infiniti Q50. The contact stated that while driving approximately 70 - 80 MPH and attempting to accelerate, the vehicle would accelerate but failed to exceed 10 MPH. The accelerator pedal had to be depressed to the floorboard for the vehicle to accelerate; however, the vehicle still failed to exceed 10 MPH. During the failure, the check engine warning light was temporarily illuminated. The contact intended to have the vehicle towed to the dealer, which was called and informed of the issue. The dealer informed the contact that the VIN was not included in the federal safety agency Campaign Number: 21V234000 (Engine and Engine Cooling). The failure mileage was approximately 82,000.

Filed May 18, 2026 · Acceleration · TX

OUTPUT SPEED SENSOR on 2016 INFINITI Q50t - Took vehicle in for oil and filter change 2 days ago. I drove the car about 40 miles, without incident. Went back to same place for state inspection yesterday. I drove about 2 miles from the inspection place and park in shopping lot. Went in business to shop for about 30 minutes. Returned to vehicle and drove about 100 yards through the parking lot. The car appeared to lose power and made a jerking movement as if it didn't want to go. I drove out onto a very busy street and we were almost rear ended by other traffic. I pulled up in another parking lot to assess the problem. I could not determine what was causing the car not to pick up speed. I drove to an AutoZone: battery checked out at 90 percent good; no electrical problems noted either. I drove off about 1 block from AutoZone: the CEL came on for the first time. I went back to the AutoZone to get them to check it out. The diagnosis code is P0720: vehicle speed sensor. I went back to the inspection shop the next day and I was told the same code. I took the vehicle to the dealership and I was told that I need to replace the whole transmission. I purchased the vehicle about 8-1/2 years ago; garage kept; only put 60k miles on car since purchase. Car has approx. 108k miles now. This is not only a problem with 2014 -2015. When I purchased the car in 2018, I feel like the dealership should have informed me that this was a problem with Q50s. This is not just an issue with previous years; this is a problem with 2016 as well. This vehicle is very clean/outstanding: no accidents, no body damage, immaculate leather seats, no repairs in 8-1/2 years and all of a sudden this fault code comes up with no previous indication that the transmission was not working properly. There needs to be a RECALL for this vehicle due to this common issue.

Filed May 14, 2026 · Electrical, Engine · MD

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.

Filed Mar 5, 2026 · Transmission · 99,000 miles · FL

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.

Filed Aug 26, 2025 · Acceleration, Electrical · CA

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.

Filed Aug 25, 2025 · Electrical · NJ

I went into Infiniti of Massapequa for an oil change I was told that my car has a recall for the ecm and by law they’re required to fix the recall in doing that it instantly caused a check engine light and are asking me to pay out of pocket for the oil pump adapter wire harness code P06DA repairs caused by the updated ecm I don’t feel that it is fair that I have to pay for anything due to issues from the dealers update of the ecm

Filed Jul 28, 2025 · Engine · 67,500 miles · NJ

The contact owns a 2019 Infiniti Q50. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated, with an abnormal knocking sound coming from the vehicle. The vehicle was turned off; however, while attempting to restart the vehicle, the abnormal knocking sound persisted. The vehicle was towed to the dealer, where it was diagnosed with engine and turbocharger failure. The contact was informed that the engine and the turbochargers needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 67,500.

Filed Jul 14, 2025 · Transmission · LA

I received a check engine light will driving which is now indicated as code P0720 and P0500. The car refused to shift past 3rd gear and began to sputter and would not allow me to go past 25mph disrupting the flow of traffic.

Filed Jul 9, 2025 · Engine, Transmission · 94,150 miles · CA

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.