117888 | Genuine Williams Controls® Throttle Control Valve

1. Regulates Engine Airflow

• Controls the volume of air entering the intake manifold

• Works with fuel injectors to maintain the correct air-fuel ratio

2. Controls Engine Power and Speed

• Opens more for acceleration

• Closes partially at idle

• Provides smooth engine response to the accelerator pedal

3. Supports Fuel Efficiency

• Helps maintain optimal combustion

• Prevents wasting fuel by controlling airflow precisely

4. Reduces Emissions

• Maintains proper air-fuel mixture

• Works with sensors and the ECM to minimize CO, NOx, and hydrocarbons

5. Works With Engine Control Module (ECM)

• In modern vehicles, the throttle valve is usually electronically controlled (“drive-by-wire”)

• ECM adjusts the valve based on:

  • Accelerator pedal position

  • Engine load

  • Temperature

  • Airflow sensor readings

1. Check Engine Light (CEL) Turns On

• Most common indicator

• ECM stores throttle-related codes (like P0120–P0124, P2100–P2119)

2. Poor Engine Performance

• Engine hesitates, stalls, or surges

• Reduced acceleration or power loss

3. Rough or High/Unstable Idle

• Engine idles erratically or revves unexpectedly

• Idle may fluctuate up and down without pressing the accelerator

4. Throttle Lag or Delayed Response

• Slow response when pressing the accelerator pedal

• Can feel like engine “lags” before accelerating

5. Limp Mode Activation

• Some vehicles enter limp mode to protect the engine

• Limits speed and power to prevent damage

6. Stalling

• Engine may stall at stoplights or during low-speed maneuvers

7. Poor Fuel Economy

• Incorrect throttle positioning can cause the engine to run too rich or too lean

• Leads to increased fuel consumption

8. Reduced Power or “Engine Hesitation”

• Difficulty accelerating

• Engine may surge unexpectedly at constant speed