Loading...

Infiniti Q45 Fuel Injection Throttle Control Actuators

Infiniti Q45 Fuel injection throttle control actuators

Starting at low prices, AutoBuffy stocks multiple fuel injection throttle control actuators from top OE-quality brands. This actuator controls the throttle plate position electronically, replacing the mechanical cable between the accelerator pedal and the engine. When it fails, the engine loses precise air-fuel control, causing hesitation, limp mode, or a complete no-start condition.

Signs your Infiniti Q45 needs a new fuel injection throttle control actuator

  • Illuminated check engine light with throttle-related codes such as P0120–P0124 or P2100–P2119
  • Engine enters limp mode, limiting vehicle speed to 20–40 mph with sluggish throttle response
  • Rough or unstable idle that hunts up and down at a stop
  • Sudden loss of power or hesitation during acceleration, especially from a standstill
  • Throttle pedal feels unresponsive, sticky, or requires unusually heavy pressure to accelerate
  • Engine stalls unexpectedly or fails to start while the throttle body motor is audibly not moving on key-on

Which fuel injection throttle control actuator should you buy for your Infiniti Q45?

The main decision is whether to buy a standalone actuator motor or a complete throttle body assembly that includes the actuator pre-installed. Fit matters more than brand here — sensor calibration and connector type must match your Infiniti Q45's ECU exactly. Consider whether your existing throttle body housing is in good condition before choosing a motor-only replacement.

OEM-Equivalent Actuator Motor (motor only)
Best for
Throttle body housing in good condition with no sensor faults
What you get
Direct-fit replacement motor that bolts into your existing housing; most cost-effective if the rest of the unit is undamaged
Remanufactured Complete Throttle Body Assembly
Best for
High-mileage vehicles where the bore, sensors, and motor are all worn
What you get
Pre-calibrated unit with actuator, TPS sensors, and cleaned bore; reduces reinstallation variables and recalibration risk
OEM Dealer-Sourced Actuator
Best for
Vehicles still within powertrain warranty or where ECU relearn is strictly calibration-sensitive
What you get
Exact factory specification; highest cost but eliminates any compatibility concern on finicky drive-by-wire systems
Performance / High-Flow Throttle Body with Actuator
Best for
Modified engines needing increased airflow beyond the stock bore diameter
What you get
Larger throttle bore with integrated actuator; requires ECU tuning to match the new airflow curve — not a drop-in replacement

Replacing a fuel injection throttle control actuator on a Infiniti Q45

Moderate⏱ 1–2 hoursSocket set and ratchet (metric)Flat-head and Phillips screwdriversOBD-II scan tool (for fault code clearing and throttle relearn)Throttle body cleaner and clean ragsTorque wrench

Disconnect the battery and remove the air intake duct to access the throttle body on your Infiniti Q45, then unplug the electrical connector and unbolt the throttle body or actuator motor depending on which component you are replacing. Transfer any gaskets or seals, install the new part, and snug the fasteners evenly without over-tightening against the intake manifold mating surface. Reconnect the battery, clear stored fault codes with a scan tool, and perform the manufacturer-specified throttle position relearn procedure before test-driving.

Frequently asked questions

How much does it cost to replace fuel injection throttle control actuators on a Infiniti Q45?
Parts start at low prices for a Infiniti Q45 throttle control actuator at AutoBuffy. A standalone motor costs less than a full throttle body assembly. Add one to two hours of labor at a shop. Many owners do this replacement at home, keeping total out-of-pocket cost close to the part price alone.
Do I need to relearn or recalibrate the throttle after replacing the actuator on a Infiniti Q45?
Yes, in most cases. After installing a new throttle control actuator on a Infiniti Q45, the ECU needs a throttle relearn procedure to establish the new closed-throttle reference position. This is often done by cycling the ignition without starting, or with a scan tool. Skipping this step commonly causes rough idle or a check engine light.
Can I drive my Infiniti Q45 with a faulty throttle control actuator?
Not safely, and often not far. A failing actuator on a Infiniti Q45 typically triggers limp mode, which severely restricts engine output to protect the drivetrain. In more advanced failure, the throttle may stick open or closed. Driving in this condition risks loss of vehicle control or secondary engine damage and should be avoided.
Will replacing just the actuator motor fix the problem, or do I need the whole throttle body?
It depends on what failed. If only the motor is worn or burned out and the throttle position sensors and housing bore are clean and undamaged on your Infiniti Q45, a motor-only replacement is sufficient and more economical. If stored fault codes indicate sensor failures alongside the actuator, or if the bore is dirty and scored, a complete assembly is the better value.
What causes a throttle control actuator to fail on a Infiniti Q45?
The most common causes are carbon buildup restricting the throttle plate, corrosion inside the motor from moisture intrusion, and worn internal motor brushes after high mileage. On a Infiniti Q45, electrical issues like a damaged wiring harness or poor ground connection to the throttle body can mimic actuator failure and should be checked before replacing the part.
Is a fuel injection throttle control actuator the same as an electronic throttle body?
They are related but not identical. The throttle control actuator is the electric motor and gear mechanism inside the throttle body that physically moves the throttle plate. The electronic throttle body is the complete assembly, which includes the actuator, throttle position sensors, and the housing. On a Infiniti Q45, you can often buy and replace just the actuator motor separately.

More parts for your Infiniti Q45

A/C Suction Line HoseEngine Camshaft Position Sensor CoverDrum Brake Hardware KitFuel FilterPCV ValveMass Air Flow Sensor ConnectorBrake Pad Wear SensorHorn Relay