Regular speed sensor maintenance checks are crucial for any vehicle owner's responsibilities. The National Highway Traffic Safety Administration (NHTSA) estimates about 250,000 crashes per year in the United States caused by faulty speed sensors. This article will cover why you should keep your speed sensors in check and some tips for doing so.
What are speed sensors, how do they work, and what do they do?
You've probably noticed the many sensors on your vehicle; whether it's a speed sensor or an air-quality sensor, these devices are there to monitor the environment surrounding your vehicle.
Mechanical speedometers have been in use for 100 years, but electronic speed sensors have only been around since the 70s. Speed sensors come in two varieties: those that measure wheel revolutions and those that measure axle rotation.
In either case, they work by using a magnetic field from a permanent magnet to activate a reed switch. The electricity from this simple setup is used to send information about your car's movement to other car parts so they can adjust themselves accordingly.
A typical speedometer with a mechanical odometer and a digital readout.
The difference between a speedometer and a speed sensor is that the latter reads information from your car's transmission, whereas the former displays it. In most cases, your vehicle's speedometer is an electronic display of data sent from a speed sensor.
Why Should You Keep Your Speed Sensors On Check?
The main reason you should keep your speed sensors in check is that they can fail unexpectedly. This failure results in either no odometer readout or a false reading above or below what you are traveling at.
Let's take a closer look at the ten most common negative consequences of ignoring checking your speed sensor regularly:
#1: Speedometer Failure: $2000+ to Replace
The most common negative consequence is the malfunctioning speedometer. This will happen when your car's computer receives inaccurate information from your speed sensor, and it sends that information to your car's instrument cluster.
You'll see a warning light on your dashboard, and you won't know your actual speed. This is especially dangerous when traveling at high speeds because you'll have no idea how fast you're going.
A faulty speed sensor can result in a faulty speedometer readout.
#2: Malfunctioning Cruise Control: $300 to $500 for Repairs
Cruise control is another feature that uses speed sensors to determine your car's actual speed. If the speed sensor fails, your cruise control will also stop working.
This is a problem because the system makes automatic adjustments to maintain a constant traveling speed. However, it'll be unable to do so if it isn't receiving any signals from the faulty speed sensor.
#3: Steering Disabled: $1000+ for Repairs
Disabling your steering can be very dangerous because it will leave you no control over your vehicle's speed, direction, or braking. This is because the information from the faulty speed sensor controls a car's computer, and if that information is faulty, so too will be your car's steering and brakes.
Your car may continue to drive forward if it senses it is going downhill even though you have come to a stop on an incline. Or, you could find yourself driving in reverse when you intended to go forward into traffic after stopping at a red light.
A faulty speed sensor can cause lost steering control or brake failure.
#4: Transmission Failure: $1500 to Fix
Transmissions are highly sensitive to inaccurate information from speed sensors. A faulty reading can send false signals to your transmission, which sends more power to the wheels than they can handle.
Your car must be receiving accurate information from a speed sensor because of how the transmission works. In addition, your car has a computer that monitors all of your engine's parts and makes adjustments accordingly.
In addition to controlling the throttle, it also provides clutch pressure for manual transmissions. This way, when you need more or less torque for changing gears, it changes the appropriate variables, so there are no surprises while you drive.
A failure in either part can lead to serious transmission damage.
#5: False Speed Sensor Warning Light: $20 to Check for When You Get it Repaired
The most common cause of a false speed sensor warning light is a faulty sensor, but not every malfunction means the speedometer is broken. You may occasionally see this light flash on and off when driving at slow speeds, especially if your speedometer isn't working properly.
Even if your car is telling you that there's an issue with the speed sensor, confirm what the actual problem is before taking it in for repair, so don't pay more than you need to.
#6: Wrong Odometer Readout: $20-$50 Diagnostic Check-Up Fee at Your Local Auto Shop
Having an inaccurate odometer is one of the minor problems of a faulty speed sensor. However, it won't affect your gas mileage, and it won't cause any issues with steering or braking.
This is because your car's odometer doesn't rely on information from the speed sensor to work properly; it's only when you add in extra components like your cruise control and transmission that such discrepancies become an issue. If you notice this problem, keep track of how many miles you've driven since the last time you checked and then take it into a mechanic if the discrepancy grows too large.
#7: Wrong Fuel Economy Readout: $5 at Your Local market for a Calculator
Does your dashboard display an inaccurate fuel economy reading? It's possible that the speed sensor is to blame.
The information from a speed sensor helps determine how much gas you get per gallon, so if it isn't receiving any information at all, then neither will your car. This can lead to problems because having an accurate reading of your remaining fuel allows you to plan accordingly when traveling long distances or in case of emergencies.
#8: Noisy Steering: $25 to Check the Power Steering Fluid
If you have a noisy steering wheel, it's possible that your power steering system isn't working properly. As a result of this incorrect information from the speed sensor, the computer either gives you more or less assistance when turning your steering wheel or prepares for a potential hazard that might require more power.
It's recommended that you visit a mechanic or dealership to check your steering system for leaks and other potential problems.
#9: Erratic Braking: $40 at Your Local Auto Shop to Check the Wiring
A faulty speed sensor can lead to inconsistent braking, which is dangerous because you should always know how much power you have when stopping. If your brake pedal feels too sensitive or not sensitive enough, it's possible that the speed sensor isn't working properly.
Depending on where the problem is, your brakes may come on without any pressure release or vice versa. This can lead to brake failure if the car isn't prepared for the amount of pressure needed to stop.
#10: Erratic Handling: $25 at Your Local Auto Shop to Check the Wiring
Driving on a flat straight road is very different from driving in bustling city traffic with its sharp turns, sudden lane changes, and cyclists encroaching upon your path. Having an accurate speed sensor ensures that your car knows how fast it's going and prepares for the change in terrain accordingly.
Suppose you feel like your car isn't handling correctly. In that case, there's a chance that the speed sensor is either receiving incorrect information or isn't giving your car enough information to pass along to its other components.
Visiting a mechanic or dealership is the best option in this situation because they'll be able to easily pick up on the problem and give you an accurate estimate of how much it will cost to fix.
How can you check your speed sensors to ensure they're working properly?
If you suspect there is an issue with your vehicle's speed sensor, you can follow these steps to diagnose:
Step#1: Activate your ABS and apply the brakes with moderate pressure. If the vehicle continues to skid, this is a sign that there is an issue with your speed sensors.
Step#2: Activate your cruise control system and accelerate until you reach 55 mph. Look at the MPH display on the dashboard, and if it doesn't match your speed, there is an issue with your speed sensors.
Step#3: Activate the park sensor system and start in reverse or drive while pressing the brake pedal down three-quarters of the way. If you're unable to start forward, this is a sign that there could be an issue with your vehicle's speed sensors.
What should you do if you find that your speed sensors need repairs or replacement?
If you find that your speed sensors need repairs or replacement, it's best to visit a mechanic or dealership. They have access to OEM parts and can accurately diagnose the problem.
You must have your car's speed sensors regularly tested because they play an integral role in how your vehicle works.
If you suspect that there is a problem with one of them, bring your vehicle to a mechanic as soon as possible so they can repair the damage before it has a more serious consequence on other components beyond the speed sensors themselves.
Modern cars rely heavily on computers. Their readings from these computers are used for all of the essential functions such as gear shifts, braking, acceleration, air conditioning, climate controls, and more.
Suppose you've recently been experiencing problems with your vehicle that seem to be caused by faulty working from the speed sensor. In that case, there are a few warning signs to look out for so you can catch them early before they lead to potentially dangerous situations on the road.
#1: You're Able to Put Your Car into Drive or Reverse but Not Neutral
To shift from drive into neutral on a manual transmission, you need to shift gears as though you're driving up a hill because doing this disengages your clutch system, which is what connects your car to the transmission.
If you're able to get your car into drive or reverse but not neutral, it's a sign that there's an issue with your speed sensors because they provide the necessary information for this function.
#2: You Can't Put Your Car into Drive or Reverse at All
To shift from drive into reverse on a manual transmission, you need to shift gears as though you're driving up a hill because doing this disengages your clutch system, which is what connects your car to the transmission.
If you can't get your car into either drive or reverse at all, but other functions such as steering and stopping continue to work properly, there is likely an issue with your vehicle's speed sensors.
#3: Your Tires Skid When you Accelerate or Brake
When your vehicle is experiencing issues with its speed sensors, it can cause problems with how your brakes and throttle are calibrated.
You may have trouble accelerating because of faulty readings from the speed sensor that tell your car that you're already traveling at a high rate of speed, or if this problem occurs while braking, there could be inaccurate readings that make the car believe you're pressing down harder on the brake than you are.
If any one of these warning signs occurs during normal driving conditions, it's best to get in touch with an expert as soon as possible so they can diagnose why your vehicle isn't working properly.
Additional tips for keeping your speed sensors in good condition:
Speed sensors are designed to last for an extended time, typically around ten years. However, they will stop working properly over time if they are not kept in good condition or repaired when issues arise.
There are some things you can do to prolong the life of your speed sensors and prevent them from wearing out rapidly due to excess use.
For example, lowering your vehicle's RPMs after braking will reduce the stress on the gears that connect your car's transmission to its speed sensor. A sign that this may be necessary is if your car starts making a loud whirring noise while slowing down but isn't using any other warning signs like skidding or having trouble shifting gears.
Here are some additional tips to prevent premature speed sensor damages:
Drive slower than usual
Braking and accelerating too much or too harshly can put excess strain on your speed sensors and cause them to break down faster.
Make sure you're driving at a more appropriate speed for whatever situation you're in, such as if there's slower traffic ahead of you on the highway. Driving at a slower speed will make it easier for your car's computer system to keep up with its readings from the speed sensor and provide you with accurate information about its current location.
Don't use cruise control very often.
If your car has cruise control, using it too often can damage your vehicle's speed sensor since this function works by telling the car that it needs to maintain a constant speed based on how fast it's currently traveling.
Since the speed sensor calculates how fast your car is moving, using cruise control can cause it to wear out faster than usual because there are no fluctuations in its readings that would otherwise happen when you're driving manually.
Keeping your speed sensors in good condition is important because they provide the necessary information for this function.
There are three signs that you may need a replacement: if there's an issue with your car shifting gears, skidding tires when accelerating or braking, or having trouble maintaining a constant vehicle speed.
If any of these warning signs occur during normal driving conditions, it's best to get in touch with an expert as soon as possible so they can diagnose why your vehicle isn't working properly.
You can do some things to prolong the life of your speed sensors and prevent them from wearing out rapidly due to excess use, such as slowing down after braking or using cruise control less often than usual.