Most Common Infiniti Check Engine Codes (G35, G37, Q50, QX50/60/80, FX)

Understanding Infiniti Check Engine Codes

Infiniti is Nissan's luxury division, and every Infiniti shares its platform, engine, and electronics with a Nissan counterpart. The G35 and G37 (and the later Q50/Q60) use the FM platform shared with the Nissan 350Z/370Z. The QX60 is a rebadged Nissan Pathfinder. The QX80 shares its platform with the Nissan Armada. The FX35/FX37 (later QX70) shares the FM platform with the G-series/350Z/370Z -- not the Murano, which is a front-wheel-drive D-platform vehicle unrelated to the FX/QX70's chassis. The VQ-series V6 engines (VQ35DE, VQ37VHR) are among the most widely produced luxury engines in the world and are found across the entire Infiniti lineup. Because Infiniti and Nissan share identical powertrains and ECUs, every check engine code on an Infiniti has the same meaning, causes, and fixes as on the equivalent Nissan model. The primary difference is that Infiniti dealer parts cost more than Nissan dealer parts for the exact same component.

P0011 -- Intake Camshaft Position Timing Over-Advanced (Bank 1)

P0011 on Infiniti vehicles with the VQ35 or VQ37 engine indicates the intake camshaft on Bank 1 is more advanced than the ECU commanded. The most common cause is a failing variable valve timing (VVT) solenoid, also known as the oil control valve. The solenoid costs $40-$80 for an aftermarket unit and is located on the front of each cylinder head. Replacement takes 30-45 minutes. On the G35 with the VQ35DE, the VVT solenoid screen can clog with oil sludge if oil changes have been extended beyond the recommended interval. On the G37 and Q50 with the VQ37VHR, the more advanced VVEL (Variable Valve Event and Lift) system adds additional actuators that can fail. P0011 is often accompanied by P0021 (same issue on Bank 2) and P0014 or P0024 on high-mileage cars. Use only the specified oil weight (0W-20 for newer VQ37VHR, 5W-30 for older VQ35DE) and change every 5,000 miles.

P0021 -- Intake Camshaft Position Timing Over-Advanced (Bank 2)

P0021 is the Bank 2 equivalent of P0011 on Infiniti V6 engines. Community sources on the RWD VQ35/VQ37 platforms (G35, G37, Q50, FX) are mixed on which side is Bank 1 vs Bank 2 -- verify against a factory service manual for your specific chassis before using bank side to decide which side of the engine to open up. QX60 uses a transverse VQ35 layout, where bank assignment also needs FSM confirmation rather than assuming it mirrors the RWD cars. The same causes apply as with P0011 -- typically a failing VVT solenoid or oil-starvation-related damage. When P0011 and P0021 appear together, both VVT solenoids should be replaced since they share the same age, oil exposure, and operating hours. On the FX35 with the VQ35HR, rear-bank access is more difficult and professional labor adds $200-$400 to the repair. On the QX60 with the VQ35DE in transverse layout, access to both banks is limited by the tight engine bay; many shops remove the upper intake manifold to access the rear bank VVT solenoid.

P0300 through P0306 -- Cylinder Misfire Codes

Misfire codes on Infiniti V6 engines are most commonly caused by failing ignition coils. The VQ35 and VQ37 use coil-on-plug ignition with six individual coils, and failure rates increase after 80,000 miles. A single-cylinder code like P0303 (cylinder 3 misfire) points to that specific coil. Replace the failed coil ($40-$90 per coil for quality aftermarket) and the matching spark plug at the same time. Consider replacing all six plugs if they are older than 60,000 miles. On the G35 coupe and G37 sedan, the rear bank coils (cylinders 2, 4, 6) are harder to access but still DIY-friendly with patience. On the QX60, access to the rear bank requires removing the upper intake manifold. P0300 (random misfire) with no single-cylinder code often points to a fuel system issue -- a failing fuel pump, clogged injectors, or low fuel pressure. On the G35 and older models, the crankshaft position sensor and camshaft position sensors can also cause random misfires.

P0420 and P0430 -- Catalyst System Efficiency Below Threshold

P0420 (Bank 1) and P0430 (Bank 2) indicate the catalytic converters are no longer cleaning exhaust gases efficiently. On Infiniti V6 engines, primary catalytic converters are close-coupled to the exhaust manifolds, running at very high temperatures and eventually failing. The 2003-2006 G35 with the VQ35DE had a well-known issue where the pre-cats overheat, crack, and break apart internally, restricting exhaust flow and causing performance loss and check-engine codes. If you own a G35 of this vintage, have the pre-cats inspected carefully and replace them before they fail completely. Replacement primary cats cost $600-$1,200 each aftermarket, and some owners install aftermarket high-flow cats or test pipes (not road-legal in most states). On the newer Q50 with the VR30DDTT twin-turbo V6, cats are more durable but still fail eventually. Before replacing any catalytic converter, check the downstream oxygen sensors ($80-$150 each) -- lazy sensors can trigger P0420/P0430 on healthy cats.

P0101 -- Mass Air Flow Sensor Performance

P0101 on Infiniti vehicles indicates the MAF sensor reading is inconsistent with other engine parameters. The most common cause is contamination -- oil from the air filter (especially aftermarket oiled filters like K&N) can coat the MAF sensor wire and throw off readings. Clean the MAF sensor with MAF-specific cleaner spray ($10-$15) before replacing. If cleaning does not resolve the code, the MAF sensor itself is $100-$200 for a quality OEM replacement. Do not buy the cheapest aftermarket MAF sensors -- they are frequently out-of-spec and cause more problems than they solve. On the G35 and G37, the MAF sensor is in the air intake tube between the air filter and throttle body. Use Hitachi (OEM supplier to Nissan/Infiniti) or Denso for reliable aftermarket replacement. Other causes of P0101 include a torn air intake boot (common on older G35s with higher mileage) and a dirty throttle body that affects airflow patterns.

P0340 -- Camshaft Position Sensor Circuit

P0340 on Infiniti indicates a problem with the camshaft position sensor on Bank 1. Symptoms include extended cranking, stalling, and rough running. The cam sensor is located on the front of the cylinder head and costs $60-$120 for an OEM-quality replacement. On the G35 and FX35 with the VQ35DE, P0340 is a common code after 100,000 miles due to sensor heat exposure. Replace with a Hitachi or Niles (Nissan OEM supplier) sensor for best reliability. Avoid cheap aftermarket units, which often fail quickly or read incorrectly. On the G37 with the VQ37VHR, the VVEL system adds complexity and P0340 can indicate issues with the VVEL actuator rather than the cam sensor itself. Read all pending codes and freeze frame data before replacing parts -- the VVEL system requires specialized diagnostic knowledge.

P0345 -- Camshaft Position Sensor Circuit (Bank 2)

P0345 is the Bank 2 equivalent of P0340 on Infiniti V6 engines. Same causes and fixes apply -- typically a failing camshaft position sensor on the passenger-side head (for RWD models) or driver-side (for FWD/QX60). When P0340 and P0345 appear together, both cam sensors should be replaced since they have the same age and heat exposure. Labor is more involved on the rear bank of transverse-mount V6s (QX60). Cost for both sensors installed is $250-$500 at a shop, or $120-$200 DIY. These sensors are a cheap insurance replacement on high-mileage cars since they cause intermittent stalling and hard-starting when they start to fail.

P0744 -- Torque Converter Clutch Intermittent (CVT Issues)

P0744 on CVT-equipped Infinitis indicates an issue with the torque converter lockup clutch or related electronics. The QX60 (3.5L VQ35DE with JATCO CVT) is the most common Infiniti with CVT issues -- it shares the same CVT as the Nissan Pathfinder and Altima V6, which has a poor reliability record. Symptoms include shuddering during acceleration (especially between 30-50 mph), whining noise, and erratic shifting. Nissan/Infiniti's 10-year/120,000-mile CVT warranty extension applies to 2003-2010 model-year vehicles; the QX60 (2013+) was addressed by separate, later class-action settlements with their own narrower terms (e.g. the 2015-2018 QX60 settlement extended coverage to 96 months/96,000 miles) -- check the settlement specific to your model year rather than assuming the 10yr/120k figure applies. If out of warranty, a CVT rebuild costs $4,000-$7,000 and a new CVT from dealer is $6,000-$10,000 installed. Used CVTs from salvage are risky unless low mileage. Regular transmission fluid changes every 30,000 miles with Nissan NS-3 fluid help extend CVT life. The Q50 3.0T uses a 7-speed automatic (not CVT) and has much better transmission reliability.

P0456 -- EVAP System Very Small Leak Detected

P0456 indicates a very small leak in the evaporative emissions system. On Infiniti vehicles, the gas cap is the first suspect -- replace with an OEM cap ($20-$40) and clear the code. If the cap is fine, check the EVAP purge valve and vent valve, both commonly located near the charcoal canister. On the G35 and G37, the EVAP canister is located near the fuel tank under the rear of the vehicle and is exposed to road debris. On the QX80 (and Nissan Armada), the EVAP system has been recalled multiple times for various leak issues -- check for open recalls through Infiniti's recall lookup by VIN. A smoke test ($80-$150) is the most efficient way to locate a very small EVAP leak, since P0456 can be caused by leaks too small to see or hear.

Infiniti Model-Specific Issues

The G35 (2003-2007) uses the VQ35DE engine and is generally reliable but has known pre-cat failure and timing chain tensioner issues on 2003-2005 models. The G37 (2008-2013) uses the VQ37VHR with VVEL and is one of the best-built Infinitis, though the rear brake calipers are known for sticking. The Q50 (2014+) replaced the G37 and offers multiple engine options including the VQ37VHR, the V6 hybrid, and the newer VR30DDTT twin-turbo V6. Early Q50 models had issues with the direct adaptive steering system. The QX60 (2014+) is a rebadged Pathfinder and shares the CVT reliability problems. The QX80 (2014+) uses the 5.6L VK56VD V8 and is generally reliable but has well-known issues with front suspension bushings and air suspension on higher-trim models. The FX35/FX37 (later QX70) uses the G-chassis underpinnings with a more dramatic body style; mechanically very similar to the G-series coupes and sedans.

DIY Tips for Infiniti Owners

Infiniti vehicles are generally DIY-friendly for common maintenance like oil changes, brakes, and ignition coils. Rear-bank access on V6 models is challenging but doable with patience. For OBD-II scanning, any standard scanner reads Infiniti powertrain codes. For enhanced diagnostics including transmission (CVT), ABS, and airbag codes, use a Nissan/Infiniti-compatible scanner like the Autel MaxiDiag or the Nissan Consult 3 Plus. The Bluetooth OBDLink MX+ with the Forscan app reads many enhanced Nissan codes for a fraction of dealer tool cost. Use OEM or Hitachi/Niles/Denso parts for sensors and ignition components -- cheap aftermarket MAF sensors, cam sensors, and ignition coils are a major source of repeat failures on Infinitis. Join MyG37.com, G35Driver.com, or MyQ50Forum.com for model-specific DIY guides and parts sourcing. Nissan part numbers cross-reference to Infiniti for most components and are often less expensive when purchased at a Nissan dealer.

Frequently Asked Questions