Vacuum modulator functions, failure symptoms and replacement cost

August 13, 2017 | Car symptoms

In this article we are going to discuss about basic functions of vacuum modulator, common failure symptoms and also the average replacement cost.  For more information read full article below:

The Basic Functions

A lot of people take shifting gears in their vehicle for granted. But every time you shift gears, there is a vacuum modulator inside of your vehicle which ensures that your shift command can be accomplished. The vacuum modular is a load sensor inside of the engine which calculates how much of a load is being placed on the engine of your car. Once it detects this amount, it can allow the transmission to shift appropriately. Older model vehicles used to have cables connected to the throttle valve to accomplish this task. The vacuum modulator has a vacuum line which is attached to the intake valve and calculates the engine’s vacuum amount. Either way, both technologies have the same function.

When we talk about the load on the engine, we are referring to how hard it must work just to maintain its functionality. The load is obviously referring to the weight and pressure placed on the engine as it continues to move the vehicle. For example, when you drive your car downhill, there is a smaller load on the engine because gravity is helping the vehicle move. On the other hand, when you’re driving up a hill with lots of people in your car, the load on the engine is going to be much greater. The vacuum modulator measures the amount of this load so that the engine knows how hard to work to sustain the demand being placed on it.

Top 4 Symptoms

Most modern vehicles have a vacuum modulator in them. If your vacuum modulator were to become defective, there are certain symptoms you could recognize right away to determine this. Below are some of the main symptoms of a malfunctioning vacuum modulator.

  1. Bad Engine Performance– The main symptom you will notice is a weaker engine performance. If the diaphragm of the vacuum modulator were to have a leak in it, you will have a leaky vacuum and your EGR system will shut off. If the vacuum leak is too severe, then you will notice less power in your engine as well as acceleration problems. This will ultimately affect the fuel economy and efficiency of your vehicle.
  2. Engine Warning Light – Another easily noticeable symptom of a bad vacuum modulator is having the engine warning light illuminate on your dashboard. The computer of your car will know right away when the modulator sends a bad signal, which will cause the warning light to come on. However, there are many reasons why the engine warning light can come on besides this reason. So, do not automatically assume it is a bad vacuum modulator unless you are experiencing the first symptom that was discussed as well.
  3. Excessive Emission Amounts – If you have excessive amounts of nitrogen dioxide emissions coming out of your vehicle, this clearly indicates that the vacuum modulator is no longer able to properly regulate these emissions. Most people find this out when they have an emissions test done on their car, which is required by some states.
  4. Shifting Problems – If you’re experiencing all of the above symptoms while having shifting problems too, then you definitely have a bad vacuum modulator. As you just learned, the vacuum modulator is what allows the transmission to shift properly. Having a bad vacuum modulator will obviously affect

Read also: The Difference between full synthetic and synthetic blend oil

The Average Replacement Cost

If you end up having to get your vacuum modulator replaced, you will only have to spend between $100 to $200 for a new one. Depending on the make and model of your vehicle, the cost of a new part will be around $40 to $100. The labor costs are typically only $50 to $70 because it doesn’t take the mechanic that long to replace it.

Related For Vacuum modulator functions, failure symptoms and replacement cost