If you have ever been pulled over or gotten a speeding ticket, there is a pretty good chance that you doubted that you were going as fast as they may have said that you did. One thing that contributes to uncertainty when it comes to knowing your speed when driving is the engine speed sensor. The engine speed sensor sends information to the car’s computer regarding how fast the car’s engine is spinning; it sends this information by constantly recording how fast your vehicle’s crankshaft is spinning, giving you a reading on your speedometer as well. A speed sensor beginning to go bad can be the source of a wide variety of strange issues in your car and when you notice any of them it’s important to have your car looked at immediately. These speed sensors have a tendency to go bad or faulty and these are just a few indications to look for that something is going wrong.
- Improper Shifting– Without a good signal from the speed sensors, the PCM won’t be able to control the gears shifting in the transmission correctly. This can cause the transmission to shift faster than usual and a problem with the speed sensors can also impact the timing between shifts, making it take longer between shifts as well. In an automatic transmission it is hydraulically controlled so when a transmission begins to have harsher or harder shifts, it can start to damage these components and things like the valve bodies and hydraulic lines.
- Your Check Engine Light Turns On/Off– If something is wrong with the communication from the speed sensor to the car’s computer or there is no communication at all, it’s possible that the check engine light will turn on each time you accelerate. Every driver knows the stress the check engine light can bring so one that is intermittently turning on and off can be a particularly bad headache though it is often just a symptom of a bad speed sensor.
- Your Speedometer Is Erratic or Does Not Work At All– Since the speed sensor delivers the information about how fast the car’s engine is spinning to the speedometer, a speedometer that is not working at all or is giving you constantly varying readings and results that you know are improbable, it is likely an issue in the speed sensor. Whether it’s not properly determining the rate the engine is spinning or it is becoming faulty or worn down and is in need of replacing, it is important that you have your vehicle looked at immediately as knowing your speed and having proper and correct readings while out on the road is extremely important for your safety and the safety of other drivers.
- The Brakes are Harder than Normal When Just Coasting– When you aren’t accelerating at all, your brakes should be smooth and easy to pump and apply. In the event that your speed sensor is going bad or has failed, there will be no communication of engine spinning to the computer in your vehicle and in turn, even when not accelerating and just coasting, your brakes will be much harder to apply and will feel stiffer. Any trouble applying the brakes is not to be taken lightly and you should seek the help of a professional and certified mechanic to determine the issue.
Often times the transmission is a popular scapegoat for these issues among others but before you visit an expensive transmission specialist, you should take your car in for a complete diagnostic test to truly determine the cause of the issues you are having or are noticing in your car. Finding a shop with full factory level diagnostic equipment will not only ensure a more accurate reading for your car but will also make sure that you get the same level of service you would at a dealership but without the high costs or extended wait times that come from the over crowded dealer mechanics.
So the next time you get pulled over and you think you may not have been speeding, take your vehicle in to have the speed sensor checked. While it probably won’t help you get out a ticket or fight the ticket should you dispute it, a properly working speed sensor will help you ensure that you won’t have any more coming in your future.