Infiniti Q50 Common Problems & Reliability Guide
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Overview
The Infiniti Q50 is a rear-wheel-drive luxury sport sedan that replaced the G37 in 2014. Available with turbocharged four-cylinder and V6 engines — including the potent 400-horsepower twin-turbo V6 in Red Sport models — the Q50 competes against the BMW 3 Series and Mercedes-Benz C-Class. Its most controversial feature is the Direct Adaptive Steering (DAS) system, which uses electronic actuators instead of a mechanical column connection, earning mixed reviews for road feel. Common owner complaints center on DAS reliability, transmission hesitation, CVT noise (on 2.0t models), and electrical issues with the dual-screen InTouch infotainment system. Later models (2020–2024) benefited from refined software and the elimination of some early electronic gremlins.
Quick Summary
By Generation
Available Engines
Common OBD2 Codes
| Code | Frequency | Notes |
|---|---|---|
| P0507 | Very Common | Idle control system RPM high is one of the most frequently reported codes on 2014–2016 Q50s with the 3.7L V6. The engine idles rough or surges at startup, typically caused by a dirty or failing throttle body. Cleaning or replacing the throttle body usually resolves it. |
| P0300 | Common | Random/multiple cylinder misfire is reported on both the 3.7L V6 and early 3.0T engines. On the V6, worn ignition coils or spark plugs are the most common culprits. On the 3.0T, carbon buildup on direct-injection intake valves is a contributing factor at higher mileage. |
| P0171 | Common | System too lean Bank 1 on the 3.7L V6, often caused by a failing mass airflow sensor or small vacuum leak at intake boot. Also appears on the Mercedes-sourced 2.0T when the air filter housing seal deteriorates. |
| P0174 | Common | System too lean Bank 2 typically pairs with P0171 on the V6 engines, pointing to a dirty MAF sensor or vacuum leak. On the 3.7L, the MAF sensor is particularly prone to contamination from oily air filter breathers. |
| P0420 | Common | Catalyst efficiency below threshold Bank 1 appears on higher-mileage 3.7L engines, especially those with persistent lean conditions that stress the catalytic converter. Downstream O2 sensor failure can also trigger this code falsely. |
| P0456 | Common | Small EVAP leak is common across all Q50 engine variants. The fuel cap O-ring is the first thing to check; cracked EVAP hoses in the engine bay are also a frequent cause. Does not affect drivability. |
| P0101 | Occasional | MAF sensor performance code on the 2.0T (M274) engine, often related to air filter housing seal failure or a dirty sensor element. Cleaning the MAF sensor with appropriate cleaner resolves most cases. |
| U0100 | Occasional | Lost communication with ECM/PCM is linked to Direct Adaptive Steering (DAS) system faults and battery voltage drops. Frequently appears after battery replacement if the steering angle sensor and DAS are not properly recalibrated. |
| P0340 | Occasional | Camshaft position sensor circuit Bank 1 on the 3.7L VQ37VHR, often caused by a failing sensor or worn reluctor ring. May cause hard starting or stalling and should be addressed promptly. |
| C1201 | Occasional | ABS control system fault appearing in conjunction with DAS warning lights. Often a cascade code triggered by low battery voltage or a DAS module communication error rather than an actual ABS hardware failure. |
| P0710 | Occasional | Transmission fluid temperature sensor malfunction reported on Q50s with the 7-speed automatic. Can cause erratic shift behavior in cold conditions or trigger unnecessary limp-home mode. |
Known Problems
The Q50's steer-by-wire Direct Adaptive Steering system is the car's most controversial component. The DAS uses motors and sensors instead of a physical column connection. Owners report sudden loss of steering assist, the system defaulting to a rigid backup mechanical mode, and multiple warning lights illuminating simultaneously. DAS module failures, steering angle sensor faults, and software glitches are all documented. Infiniti issued multiple TSBs and a recall (NHTSA 14V-373) covering DAS software. Repairs can be very expensive if outside warranty.
Typical mileage: 5,000–80,000 miles
Shop parts for this repairThe 3.7L VQ37VHR engine commonly develops a rough or surging idle, particularly when cold or at low speeds in traffic. The root cause is usually carbon buildup in the throttle body bore restricting airflow, causing the idle control system to over-correct. Throttle body cleaning every 30,000–40,000 miles is a recommended preventive measure. Severe cases require throttle body replacement.
Typical mileage: 30,000–90,000 miles
Shop parts for this repairThe 2014–2018 Q50 2.0t uses a Mercedes-Benz M274 four-cylinder turbo engine. While generally reliable, this engine is prone to high oil consumption, timing chain tensioner wear, and carbon buildup on intake valves due to direct injection. Some owners report the engine consuming a quart of oil per 3,000 miles by 60,000+ miles. Timing chain service, while rare, is expensive when needed.
Typical mileage: 40,000–100,000 miles
Shop parts for this repairThe dual 7-inch touchscreen InTouch system freezes, reboots spontaneously, or develops unresponsive touch inputs. Android Auto and Apple CarPlay were not available on most 2014–2017 models, making the system's reliability more critical. A full system reboot (hold power button) often restores function temporarily, but persistent issues may require module replacement.
Typical mileage: Any mileage
Shop parts for this repairThe JATCO 7-speed automatic paired with the 3.7L V6 exhibits hesitation or a delayed downshift response, particularly during low-speed acceleration from a rolling stop. Transmission fluid degradation accelerates the issue. Infiniti released multiple software calibration updates, and a full fluid flush often noticeably improves shift quality.
Typical mileage: 20,000–70,000 miles
Shop parts for this repairHigher-mileage 3.7L Q50s with persistent lean conditions (P0171/P0174) often develop catalytic converter deterioration earlier than expected. Prolonged lean running damages the converter substrate. Fixing the underlying lean code first is essential; otherwise, a new catalytic converter will fail again.
Typical mileage: 80,000–130,000 miles
Shop parts for this repairRecalls
The Direct Adaptive Steering system software may cause the system to enter a backup mode with reduced steering feel without adequate warning. Infiniti dealers update the DAS control unit software to improve fault detection and driver alerts.
Fuel injector O-rings on the 3.7L V6 may crack over time, allowing fuel vapor leaks near the engine — a potential fire hazard. Dealers inspect and replace affected fuel injector O-rings.
Front passenger airbag inflators manufactured by Takata may rupture upon deployment, sending metal fragments into the cabin. This is part of the broader Takata recall; dealers replace the inflator assembly.
Applies to Q50 Hybrid models. The high-voltage battery cooling fan may fail, causing the battery to overheat and potentially shut down the hybrid system while driving. Dealers replace the cooling fan assembly.
Available Engines
Common OBD2 Codes
| Code | Frequency | Notes |
|---|---|---|
| P0300 | Very Common | Random cylinder misfire is the most commonly reported check engine code on the 3.0T twin-turbo V6. Carbon buildup on intake valves from direct injection is the predominant cause at higher mileage. Spark plug and ignition coil inspection should occur at 60,000-mile intervals. Walnut blasting of intake valves is the definitive fix for carbon-related misfires. |
| P0301 | Common | Cylinder 1 misfire on the VR30DDTT is frequently caused by a fouled spark plug or failing ignition coil. The coil packs on this engine have a documented tendency to fail around 60,000–80,000 miles, and replacing all six at once is recommended when one fails. |
| P0420 | Common | Catalyst efficiency below threshold Bank 1 appears on 2018–2021 3.0T models. The downstream oxygen sensors are prone to failure and can falsely trigger this code. Confirming the sensor is the culprit before replacing the catalytic converter (a much more expensive repair) is critical. |
| P0171 | Common | System too lean Bank 1 on the VR30DDTT is often caused by a failing MAF sensor or a small vacuum leak at the turbo inlet pipe, which is made of plastic and can crack with age and heat cycling. |
| P0456 | Common | Small EVAP system leak is reported across the entire Q50 lineup regardless of model year. The fuel filler cap is the most common single-part fix; the EVAP vent valve and purge solenoid are secondary suspects. |
| P0302 | Common | Cylinder 2 misfire, often paired with P0300, on higher-mileage 3.0T engines. When multiple specific cylinder misfire codes appear together, carbon buildup rather than individual coil failure is the more likely diagnosis. |
| P0174 | Occasional | System too lean Bank 2 pairs with P0171 on the V6. On the twin-turbo VR30, a cracked or loose charge pipe between the turbocharger and intercooler is a known cause of both bank lean conditions. |
| P0234 | Occasional | Turbocharger/supercharger overboost condition appears on Red Sport 400 models during aggressive driving. Wastegate actuator wear or a faulty boost control solenoid are the primary suspects. Should not be ignored as sustained overboost can damage the engine. |
| P0130 | Occasional | O2 sensor circuit Bank 1 Sensor 1 malfunction is common on 2018–2020 Q50s with higher mileage. The upstream oxygen sensors can fail and cause incorrect fuel trim adjustments, leading to lean or rich running conditions. |
| U0155 | Occasional | Lost communication with instrument panel cluster appears when the infotainment system or CAN bus experiences communication errors, often after battery replacement or during extreme cold. Resetting the system by disconnecting the battery for 15 minutes often clears this code. |
| P0507 | Occasional | Idle control system RPM high continues to appear on base 3.0T models, particularly those with the throttle body cleaned infrequently. Less prevalent than in first-generation cars but still a documented issue. |
| P0440 | Occasional | EVAP system large leak detected on 2020–2023 models, often caused by a deteriorating filler neck seal or cracked vapor canister hose. More extensive investigation required than for P0456. |
Known Problems
The 3.0L twin-turbo V6 uses direct fuel injection exclusively, which means fuel is never sprayed over the intake valves to clean them. Over time, oil vapor from the crankcase ventilation system deposits carbon on valve stems and the back face of intake valves. By 60,000–80,000 miles, buildup can be significant enough to cause rough idle, misfires, and power loss. Walnut blasting (media blasting the intake ports with the intake manifold removed) is the standard repair. This procedure costs $400–$800 at an independent shop.
Typical mileage: 60,000–100,000 miles
Shop parts for this repairIgnition coils on the VR30DDTT twin-turbo V6 are known to fail between 60,000 and 90,000 miles, earlier than expected for a modern engine. When one coil fails, the others are typically near end-of-life, making a full six-coil replacement the most cost-effective approach. Using OEM or OEM-equivalent coils is strongly recommended; aftermarket coil quality varies significantly. Spark plugs should be replaced at the 60,000-mile service interval as neglected plugs increase coil load.
Typical mileage: 60,000–90,000 miles
Shop parts for this repairThe plastic turbocharger inlet pipe (also called the charge pipe or boost pipe) on both the 300 hp and 400 hp versions of the VR30DDTT is prone to cracking at stress points due to heat cycling and engine vibration. A cracked inlet pipe creates a boost leak that triggers lean codes, reduces power, and can cause turbo surging under hard acceleration. Aftermarket aluminum replacement pipes are a popular and more durable solution than the OEM plastic part.
Typical mileage: 50,000–100,000 miles
Shop parts for this repairThe 7-speed JATCO automatic transmission used with the VR30DDTT occasionally exhibits a shudder or vibration during light-throttle acceleration between 25 and 45 mph, which corresponds to torque converter lockup engagement. Degraded transmission fluid is the most common cause. A full fluid flush using Nissan Matic-S or equivalent fluid typically resolves the issue. Torque converter clutch wear on high-mileage examples may require replacement.
Typical mileage: 40,000–90,000 miles
Shop parts for this repairThe dual-screen InTouch infotainment system on 2018–2024 Q50s receives periodic over-the-air updates but continues to exhibit software issues, including navigation map freezing, Bluetooth audio dropouts, and occasional full system crashes requiring a manual reboot. The 2022–2024 refreshed software is more stable, but older units that haven't received updates remain problematic. Android Auto and Apple CarPlay wireless connectivity can be unreliable on earlier software versions.
Typical mileage: Any mileage
Shop parts for this repairA portion of VR30DDTT-equipped Q50s — particularly earlier 2018–2019 examples — consume engine oil at a higher-than-expected rate of approximately 1 quart per 3,000–5,000 miles. This is attributed to piston ring seal tolerances and is more pronounced when the engine is used in spirited driving or track conditions. Infiniti considers up to 1 quart per 1,200 miles acceptable, which owners find concerning. Monitoring oil level between changes is important to avoid low-oil damage.
Typical mileage: 20,000–80,000 miles
Shop parts for this repairEvaporative emission system faults are among the most consistent check engine light causes across the entire Q50 model range. The fuel filler cap O-ring seal hardens with age and is frequently the culprit for P0456 (small leak). Vapor canister hoses and purge solenoid valves are secondary failure points. These issues do not affect drivability but will cause emissions test failures and the check engine light to remain on.
Typical mileage: 40,000–100,000 miles
Shop parts for this repairThe Q50's sport-tuned rear multi-link suspension uses rubber bushings that wear noticeably by 60,000–80,000 miles, particularly on cars driven on rough roads or in colder climates where salt exposure accelerates rubber degradation. Worn rear bushings produce clunking over bumps, imprecise handling, and tire wear. Replacing the rear trailing arm and lateral link bushings restores the car's handling precision. The job is labor-intensive at a dealer but more economical at an independent shop.
Typical mileage: 60,000–100,000 miles
Shop parts for this repairRecalls
Driver-side front airbag inflators from Takata may rupture upon deployment, projecting metal fragments into the occupant compartment. Dealers replace the front airbag inflator module as part of the ongoing Takata recall remedy.
The fuel pump control module may incorrectly reduce fuel pump output under certain conditions, potentially causing engine hesitation or stall. Infiniti dealers update the fuel pump control module software to correct the pump command logic.
A software error may cause the rear view camera image to fail to display when the vehicle is shifted into reverse, violating FMVSS No. 111 rear visibility requirements. A software update to the AV control unit corrects the camera activation timing.
Covers 2018–2021 Q50 models with conventional electric power steering (non-DAS). A software fault in the EPS control module may cause intermittent loss of power steering assist without warning. Dealers update the EPS software to prevent unexpected assist reduction.
The brake booster vacuum supply hose may crack and leak, reducing power brake assist and increasing pedal effort required to achieve normal braking force — a safety hazard. Infiniti dealers inspect and replace the vacuum hose assembly on affected vehicles.