Electronic Throttle Control Light

We know the feeling when a little lighting bolt start symbol is flushing on your vehicle’s dashboard. This warning light indicates that your electronic throttle control system has severe problems, and you need to take action to fix this.

When your ETC or Electronic throttle control light comes on, what does it mean? What are the causes? And is it safe to keep driving while the ETC light is on? Get the answers to all these queries in this post.

What is Electronic Throttle Control? And How Does It Work?

Initially, to control the engine speed, the hand throttle is used. But it faded over time and was replaced with an Accelerator pedal or Gas Pedal.

Before, the 1980 gas pedal was a mechanical link with the Engine’s carburettor through a cable. Pressuring the gas pedal opens the butterfly valve inside the Engine carburettor to increase airflow for more speed.
In model years 1990 or newer mechanical linkage is returned with a computerized system called an electronic throttle control system or ETCs.

How does ETC work? An electronic throttle control system integrated with an engine master computer called electronic control unit (ECU). When you press the accelerator pedal, the electronic throttle control opens the air control valve (ACV) for more excellent airflow. The electronic fuel injector (EFI) controlled by the ETC increases fuel flow. Thus speed increases. At the same time, ECU adjusts the timing of engine valves and ignition according to the pedal position for smooth and powerful acceleration. The throttle position sensor (TPS) signals to ECU that the air valve responds as it commands.

Whenever ETC malfunctions. The electronic throttle control warning light comes on.

What Does The Electronic Throttle Control Warning Light Mean?

Before you figure out the problem with electronic throttle control, You need to know how ETC light works in normal conditions.

When you turn on your vehicle, all the dashboard lights turn on or flash, then turn off after a few seconds. At that stage, your vehicle running system check indicates that everything works perfectly. However, if the lights do not turn off, there is a problem, and you need to fix this. But you want to know which light is not turned off and what it means.

A lightning bolt starts symbol with two vertical curved lines indicating electronic throttle control light. The ETC warning light is on if there is any problem with the throttle body, accelerator pedal, or wiring.

Electronic Throttle Control Light On: What causes it?

There are several causes of electronic throttle control light, like Faulty accelerator pedal position sensor, faulty throttle control sensor, or Stuck throttle body. We explain all these briefly below.

1. Faulty Accelerator Pedal Position Sensor

If there is a fault in the accelerator pedal position (APP) sensor, it sends incorrect information to ECM. Because of that, ECM gives wrong commands to the throttle position sensor causing the vehicle to hesitate to move. That is how the electronic throttle light comes on.

Symptoms of a Bad Accelerator Pedal Position Sensor

1. Check engine light on
2. The car hesitates to move: You will be pressing down on the gas Pedal, And the car starts to move seconds after; the reason for this is due to the APP sensor not being able to detect the exact position of the gas pedal.
3. Poor acceleration: You won’t be able to accelerate as fast as you used to because the accelerator pedal position isn’t being communicated to the ECM to make the proper commands to open up the throttle plates.
4. Experiencing your car going into limp mode: limp mode is a safety feature that protects you and your car. You’ll feel your car a lot slower, your RPMs and speed will be limited, and you’ll usually be stuck in second or third gear now since the accelerator pedal position sensor is responsible for communicating the data to the ECM to open or closing the throttle plate while driving, it puts your safety at risk if it’s failing that’s why lit mode is activated.
5. Experiencing no response when pressing down on the gas pedal: The no response happens when the accelerator pedal position sensor ultimately gives out. There have been instances where drivers are on the road, and the accelerator stops reacting. So they’re forced to pull over; this is why it’s super important to fix the problem immediately before letting it build up and get to this point.

2. Faulty Throttle Position Sensor

The throttle valve might open up, but as the sensor reads flat, no further fuel is added. When the TPS sensor fails, the position of the throttle valve is miscalculated, and ECM alters the fuel injection rates given by the faulty position sensor. This effect air to fuel ratio, and the Engine runs rough at idle. The Engine is more sensitive at an idle, And small changes in the air-to-fuel balance affect it badly.

Symptoms of a Bad Throttle Position Sensor

1. Check engine light on:
2. Shifting problems: You might be driving down the road at increasing speed and noticing a more brutal delayed shift. The reason is that the ECM can’t communicate the position of the throttle plate effectively to the Transmission Control Module (TCM) to make the shift at the perfect time.
3. Poor acceleration: The reason is that the throttle position sensor isn’t communicating the exact position of the plate to the ECM; this prevents it from making the correct fuel adjustments resulting in poor acceleration.
4. Vehicles going into limp mode limp: You’ll feel your car a lot slower, your RPMs and speed will be limited, and you’ll usually stick in second or third gear.

3. Stuck Throttle Body

Symptoms of a Stuck Throttle Body

1. Car run rough or idle rough: The car engine, when idling, is most sensitive at that time, you probably may see the RPM meter going crazy, jumping up and down with strange noises from the engine.
2. Affect your car’s acceleration or pick-up: Sometimes, when accelerating, you might feel the car acting restricted. The throttle body is also regulating the air-fuel mixture that enters the engine. When the throttle body gets damaged, the air-fuel ratio gets messed up, which causes your car to accelerate unevenly fast, sometimes slow usually, the valve gets gummed up and restricts the airflow.
3. Alter your fuel efficiency: A rotten throttle body will cause a messed-up fuel mixture which can cause a changed fuel economy as the combustion gets affected by the strange air-fuel ratio. Sometimes the fuel economy increases, but the power to the engine decreases as the fuel injection rates get lowered with altered air fuel ratios. Refueling less frequently might sound like a good thing, but your engine can get affected in the long run.
4. Can cause your vehicle to stall when idling or at the initial movement: When you start the vehicle and try to move, the gunned-up throttle body will restrict the additional airflow for the initial movement. Mostly your car shuts down with strange vibrations.
5. Check engine light on: Modern throttle body systems have airflow meters and position sensors that continuously monitor the airflow at particular valve positions. If the computer detects a change in airflow at a particular valve position, the driver is alerted with a check engine light in the dashboard.