What Happens If You Disconnect the Throttle Position Sensor?

Throttle position sensor

A throttle position sensor is required to monitor the air intake of a car engine.  Its primary function is to ensure that the correct fuel is mixed with the air for optimum results.  This can be observed when the butterfly is placed on a spindle or shaft.

If the TPS fails, the car is still drivable.  But the long-term consequences can majorly impact your car’s health.  And it can be downright dangerous.

The job of this tiny sensor is to detect throttle position and share this information with the engine control module.  This information is critical to automotive systems as it plays a vital role in airflow temperature, engine speed, and other components.

What Happens If You Disconnect, The Throttle Position Sensor?

The throttle position sensor is one of the most critical sensors in a car engine.  It significantly affects how fast or slow a car can go. Throttle Position Sensor is no longer a permanent fixture like other sensors in car engines. It means that if a significant problem occurs, it can easily disconnect from the engine.

The short answer is that the problem lies with how much air-fuel mixture the computer module needs to inject into the engine at any given time. It affects the car’s response when you step hard or lightly on the accelerator pedal with your foot.

As mentioned earlier, the throttle position sensor is vital in how fast or slow the car can go.  It explains how it allows the vehicle to move at the desired speed at any given moment.  But before that, let me explain something else related to this concept.

Now, when you want the car to go fast, you step on the accelerator pedal hard, and when you want the car to go slowly, you step on the pedal softly. These actions now affect how far the throttle valve opens to allow the air-fuel mixture into the engine.

It means these measures affect how much air-fuel mixture enters the combustion chamber at any time. When you step on the pedal with your foot, the throttle valve opens wider to let more air-fuel variety into the engine. Accordingly, the rate of combustion increases, and the speed increases.  However, if you press the pedal softly, the valve opens less. It means less air-gas mixture enters the engine, resulting in slower combustion and lower acceleration.

During pedal action, the throttle position sensor is always sharp and monitors how wide the throttle valve is open.  It then transmits this information to a computer, which, based on the data, triggers the injection of the appropriate air-fuel mixture into the engine.

When the throttle valve is wide open, the throttle position sensor tells the computer to inject the more air-fuel mixture into the engine, allowing the car to accelerate due to the increased combustion rate.

Conversely, when less open, the TPS tells the computer to send less fuel to the engine, slowing the burn.  It slows down the car.

What happens when the throttle position sensor goes bad?

Your vehicle’s throttle position sensor measures how far down the gas pedal is.  Before there were computers in cars, there was no throttle position sensor.  Automotive computerization, fuel injection, and increasing miles per gallon have made the throttle position sensor a much-needed engine part.  The computer uses the measurements provided by the throttle position sensor to adjust many engine parameters, primarily the amount of fuel supplied.

If the throttle position sensor malfunctions, the engine will not run properly.  In general, the engine idles fine but has trouble accelerating.  That’s because the computer isn’t telling the machine to inject enough fuel, and the air is increasing simultaneously.  Most vehicles will illuminate a Malfunction Indicator Light when this condition occurs, but this is not always the case as it depends on the severity of the fault.

What will happen if I unplug my throttle position sensor?

Have you ever wondered if you can drive a vehicle when the throttle position sensor is disconnected? Can a car start without a throttle position sensor?  The Throttle Position Sensor still allows the vehicle to drive.  However, the car does not perform at its best.  Read on to discover what a bad TPS can do to your vehicle.

Bad Throttle Position Sensor Causes & Symptoms?

If the TPS begins to fail, even partially, it must be replaced immediately.  Replacing the TPS involves clearing the associated error codes and may require reprogramming the new throttle position sensor module’s software to make it compatible with other engine management software.  It is best to leave it to a professional mechanic who can diagnose and install the correct replacement part.

Here are some common symptoms of a bad or failing throttle position sensor to watch out for,

  • The car does not accelerate, lacks power when accelerating, or accelerates by itself.

Does the throttle position sensor affect acceleration? Yes. The car may feel like it is not accelerating properly.  It can accelerate smoothly but lacks power.  On the other hand, there may be cases where the vehicle suddenly accelerates while driving, even when the accelerator pedal is not pressed.  If you experience any of these symptoms, the problem is likely with the throttle position sensor.

In these cases, the throttle position sensor will not provide the correct input, and the onboard computer cannot direct the engine to work correctly.  When a car accelerates while driving, it usually means that the butterfly valve inside the throttle closes and suddenly opens when the driver presses the accelerator pedal.  This gives the car unexpected acceleration as the sensor cannot detect the closed position of the throttle.

  • Engine does not idle smoothly, idles too slowly, or stalls.

If you start experiencing engine misfires, stalls, or rough idling when you pull up, it could also be a warning sign of a throttle position sensor failure.  No need to wait to check this out!

When disable appears, the computer cannot detect a fully closed throttle.  The throttle position sensor can send invalid input anytime and eventually shut down the engine.

  • The car accelerates but does not exceed relatively low speeds or shifts.

It is another failure mode of the throttle position sensor, indicating that it incorrectly limits the power requested from the accelerator pedal foot.  You’ll notice that the vehicle accelerates but doesn’t go over 20 – 30 MPH. This symptom often occurs along with power loss behavior.

  • Check if the engine light comes on with the above action.

If there is a problem with the throttle position sensor, the check engine light may come on. It isn’t always the case, so don’t wait for the check engine light before checking the symptoms above. Check the vehicle for trouble codes to determine the cause of the problem.

The throttle position sensor is critical to getting the desired power and fuel economy out of the vehicle in all driving situations.  As is evident from the symptoms listed above, failure of this component has severe safety implications and should be checked immediately by a qualified technician.

  • Do you have to reset the computer after replacing the throttle position sensor?

Replacing a broken throttle position sensor requires purchasing a new one.  Do you have to reset the computer after replacing the throttle position sensor?  What should you do after replacing the throttle position sensor? After replacing the throttle position sensor, you may need to reset or reprogram the computer to turn off the check engine light and clear the code. Among other signs of a bad throttle position sensor, the check engine light comes with a throttle position sensor code.

It’s important to know that some cars don’t need to reset or reprogram the vehicle after replacing the throttle position sensor.  This is because the check engine light automatically turns off within a few minutes of driving.

However, you need to determine the real cause of the light, as fixing it in any other way will most likely cause it to turn off on its own. To reset the throttle position sensor, do one of the following,

  • Drive your car and make sure you drive no more than 40 miles per hour.
  • Remove the fuse and let it sit for at least 10 minutes.
  • Use an OBD2 scanner. This method is easier and better to use on modern cars.

Do this by depressing the accelerator and starting the engine but not removing the key from the ignition.  If your car has a keyless start, you must press a button.

Will disconnecting the battery reset the throttle position sensor?

To reset the computer, remove the battery’s negative terminal/cable and leave it for at least 13-15 minutes.  You can then connect it to the battery to ensure it is connected securely.  It should be enough to reset the computer, turn off the check engine light and clear the codes.

If the check engine light does not go out after this, the problem is likely not with the throttle position sensor, and you will need professional help to determine the problem.


Q. Is there a way to bypass the throttle position sensor?

Disconnect the throttle position sensor, turn on the ignition, wait 30 seconds, and start the engine, which should usually begin.  It takes time for the ECU to recognize that the TPS isn’t working and adjust how it works.  Without TPS, the engine won’t work, but it works.

Q. How do I test the throttle sensor?

Set the multimeter to the 10 DC voltage range and place the black negative probe on the ground terminal of the TPS and the red positive probe on the reference voltage terminal of the TPS.  If the meter doesn’t show 5 volts, the TPS is bad.

Q. Does the throttle position sensor affect timing?

Throttle position sensors can fail in several ways, from poor fuel economy and limited performance to safety hazards to you and other drivers at worst.  Problems can arise when changing gears or setting the initial ignition timing.

Q. What Causes Throttle Body Failure?

Dust, carbon, and grime can build up in your home and cause airflow problems.  A soft service gun for the air passage, known as corking, commonly fills and unbalances the gun.  This prevents the perfect mixing of air and fuel and can cause the butterfly valve to stick.


You can remove the throttle position sensor and drive, but we do not recommend doing so. Should repair malfunctioning as soon as possible. If you can still drive your vehicle, you can cut off your rational thinking and cause more problems for yourself in the long run.

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