Carworx Ltd - Sensors Replacement

Your vehicle has a lot of sensors working tandomly with your vehicles computers to make it run smoothly and efficiently. But like any body parts these can also fail. Here we describe some of the main sensors.

MAF Sensor

The mass airflow sensor is a round tunnel made of plastic with a sensor attached inside. All cars take air from the outside and pass it into the engine through the air filter. The mass airflow sensor measures the amount of air entering the engine. For an engine to perform properly, it needs a specific amount of air-fuel mixture. The computer in the car reads the amount of air coming into the engine from the mass airflow sensor and then calculates the correct amount of fuel needed for proper engine performance. If the sensor goes bad, the engine will not know the right amount of fuel to add, causing problems including poor gas mileage, lack of power and more.

It is common for the mass airflow sensor to get dirty (if the air filter is dirty) and lose the ability to read the amount of air coming in the engine. If the vacuum hoses are leaking, it will give the same error code as mass airflow sensor failure.

Camshaft Sensor

The camshaft position sensor monitors the position of the camshaft and reports that data to the car’s onboard computer system. This computer system works with sensors and other devices to keep the engine running. With data from the camshaft position sensor (CPS), the fuel injectors know when to fire.

When the sensor malfunctions, the computer does not know when to fire the injectors and may not fire them at all. The faulty readouts may also throw off spark timing, which will affect the car’s fuel economy. This sensor is used in conjunction with the crankshaft position sensor to control ignition timing. It is common for heat and oil leaks to cause this sensor to fail, due to where the sensor is located.

Crankshaft Sensor

Many newer cars have computerized engine management systems that rely on sensors to report data to the computer. The crankshaft position sensor is used in conjunction with the camshaft position sensor to control ignition timing and to let the computer know when to inject fuel and provide spark sequence. Due to the mounting locations of this sensor, it is common for heat and oil leaks to cause this sensor to fail.

Oxygen Sensor

With each new model year, manufacturers are adding more oxygen sensors to better manage engine operation. Some high performance engines have an oxygen sensor for each cylinder as well as one for the rear of each catalytic convertor. The sensors are located either underneath the hood or underneath the car. The oxygen sensors are connected (screwed) to the exhaust pipe, either in front or back of the catalytic converter. The front (upstream) sensors measure the amount of oxygen in the exhaust system. The purpose of the front oxygen sensor(s) is to measure how rich or lean the gases are as the gases exit the combustion chamber.

Depending upon whether the exhaust gas is lean (high in oxygen content) or rich (low in oxygen content), the amount of fuel entering the engine is adjusted by the engine management computer to try and maintain an ideal mixture that produces the lowest emissions output from the catalytic convertor.Rear (downstream) sensors are located behind the catalytic converter. The purpose of the rear oxygen sensor(s) is to monitor the oxygen content of the exhaust gases leaving the catalytic convertor.If one or more of the oxygen sensors are faulty, your car may not pass the emissions test. If you drive your car with a faulty oxygen sensor, you may get poor gas mileage and it can damage the catalytic converter.

Coolant Level Sensor

The coolant level sensor is designed to alert the driver when the coolant level is low and to prevent overheating or damage to the engine. This aids in diagnosing leaks and other dangerous cooling system conditions.Coolant level sensors can consist of a plastic sensor with a plastic or foam float that sits underneath the coolant reservoir cap. Or, they can be plastic sensors that plug into the radiator or other component of the cooling system.Some vehicles are equipped with a Low Coolant or Check Coolant warning light, while others may display a picture of the vehicle with a red dot in the engine bay. This is to inform the driver that the coolant needs to be checked or that there is a fault with the sensor.

ABS Speed Sensor

Most modern vehicles have anti­-lock brake systems that use sensors to detect wheel rotation rates, reporting to a computer that is able to modulate brake pressure if one or more wheels should lock during a braking operation. Usually the sensor is a Hall­effect, or so-­called reluctance component, which looks at a toothed ring (called a tone ring) that is affixed to the wheel or axle. The teeth passing by the sensor creates a wave form that can be recognized and interpreted by the ABS controller. On three-channel ABS systems (typically found on older pickups), the rear axle is monitored by one sensor while the front wheels have their own individual sensors and anti­-lock control. Four-channel systems monitor each wheel independently.

Instrument Voltage Regulator

It’s important for drivers to have access to a wide range of information while behind the wheel. This includes vehicle speed, RPM, fuel level, coolant temperature and much more. The information needed is displayed for the driver on gauges – the fuel gauge, the speedometer, the tachometer, etc. This is the instrument cluster. Like many other elements of your vehicle, the modern instrument cluster is electronic, and requires voltage in order to operate. The instrument cluster consumes less power than batteries do (Batteries use around six volts).The instrument cluster voltage regulator ensures that the right amount of voltage is supplied. Voltage regulator failure is relatively rare, but not unheard of.

Oil Level Sensor

The vital role of the low oil level sensor is protecting your engine from friction as well as wear and tear. You need to have the right amount of oil in the engine at all times or the friction and heat will severely lower the longevity of your engine components. Today, most cars come with an oil level sensing system that determines how much oil is in the pan and transfers the information to the car’s computer. If the level is too low, the computer turns on the Low Engine Oil light on the dash, warning the driver of the problem.

The low oil level sensor is attached to a float type device in the oil pan. It measures the amount of oil present in the pan during operation. Depending on the position of the float, the sensor knows how much oil is present and sends the data to the computer. The computer compares that information with the preprogrammed readings from the automaker and determines if it’s sufficien

Manifold Temperature Sensor(Map Sensor)

Air is the single most important element for a running engine, even more so than fuel or oil. Without a flow of fresh, clean air, combustion cannot take place, and your engine cannot operate. However, simply ensuring that airflow can reach the intake is not enough. The car’s computer needs to know a lot of information about the temperature and quality of air entering the intake. The manifold temp sensor is responsible for determining the temperature of the air, and providing that information to the computer.

The computer will determine the density of the air and adjust the fuel flow to meet that. Depending on the make and model you drive, your car may have more than one manifold temp sensor. For instance, if you have a split manifold, you’ll have a sensor for each part. Like all other sensors on your car, the manifold temp sensor is subject to high heat and wear and tear. Electrical problems such as shorts and broken wires augment the list of potential troubles.

Oil Temperature Sensor

Engine oil is needed to lubricate the inner workings of your engine and prevent damage from friction. It works alongside the coolant that circulates in and around the engine to cool it. However, engine oil temperature must be strictly controlled. If the temperature crosses a threshold, engine damage can result.The oil temperature sensor’s job is to monitor oil temp and communicate the information with the car’s computer. In some models, the oil temp is actually displayed in the dash, but many newer models only display engine coolant temperature. The oil temperature sensor works in tandem with the water temperature sensor and other temperature monitors to ensure that the temperature remains within an acceptable range.

Like all other sensors, the OTS is subject to high heat on a regular basis, which can damage the wiring harness. If the oil temperature sensor fails, the oil temperature will read incorrectly or not at all.

Speed Timing Sensor

A speed/timing sensor measures the rotation of a component to determine its physical rotational speed. When it is monitored, it can be used to determine the correct air/fuel mixture, the spark advance, and variable valve timing for your engine. The speed timing sensor is a magnetic coil that is mounted stationary to the engine block and reads the teeth on the crankshaft as it rotates. As the crankshaft spins during driving, an induction current is created around the magnetic coil. The crankshaft’s serrated edge obstructs this magnetic field and the result gets recorded. This measurement is reported to the engine control module to determine how engine performance settings will be adjusted. If the crankshaft speed/timing sensor isn’t reading properly or at all, the Check Engine light will come on and engine performance will be compromised.

Speedometer Sensor

As its name implies, the speedometer displays your vehicle's real-time speed. Most speedometers are electronic. An electronic speedometer measures vehicle speed with the help of a speedometer sensor. This sensor, usually located at the transmission, detects the drive shaft's rotational speed. The sensor delivers a corresponding series of pulses to a computer, which then turns these pulses into the numerical figure the speedometer indicates. So when the speedometer sensor becomes faulty, the speedometer becomes unreliable.

Thermostatic Vacuum Sensor (Engine Coolant Temperature Sensor)

When the engine is started cold, it takes several minutes to reach operating temperature which is when the engine is running most efficiently. Vacuum is created whenever the engine is running and can be used to control one or more auxiliary vehicle options such as heater controls or cruise control, and is also used to control emissions systems such as exhaust gas recirculation, or EGR. It also controls vacuum for the distributor to advance or retard the spark, ensuring the engine runs as smooth as possible. Vacuum is supplied to these systems through hoses routed in the engine compartment. If engine vacuum was supplied to the EGR system when the engine was still cold, the engine would stumble or stall, and would do so until it reached operating temperature.

The thermostatic vacuum sensor is mounted in the intake manifold and uses coolant temperature to determine when the engine has reached operating temperature. Once it has warmed up, the thermostatic vacuum sensor opens and allows vacuum to flow through it to the vacuum-operated functions it controls. If the thermostatic vacuum sensor fails in the open position, it can be difficult to start the engine when it is cold and will run poorly until it warms up. If the vacuum sensor fails when it is closed, it may start properly but will lose power and run poorly at warm temperatures. It will burn fuel poorly, creating higher exhaust emissions that may fail a smog check. The engine light likely will come on when the vacuum sensor fails.

Throttle Position Sensor

For a car to run smoothly, it needs the proper mixture of air and fuel. The amount of air in the engine is controlled by the air intake system. A throttle body is part of the air intake system that helps control the amount of air that gets into the engine. The throttle body has a throttle plate. If the plate is closed, it prevents the air from getting into the engine. When you push the gas pedal, it opens the plate, allowing the air to enter the engine. The amount of air depends on the position of the plate, which is controlled by the gas pedal. The harder you push the gas pedal, the wider the plate will open, and more air will flow to the engine. This means more power and more speed.

The throttle position sensor reports the position of the gas pedal to the computer in your car (Engine Control Unit). The computer then determines the position of the throttle plate. It also calculates the amount of air flow to the engine and the amount of fuel to be injected for the required ratio of air-fuel mixture. The throttle position sensor also controls the shifting of the gears. If this sensor stops working, the car's computer will not be able to calculate the right amount of fuel to be injected in the system. It may not be able to change the gears. Your car will not get the right amount of power. It may not even start. The Check Engine light may come on.

Yaw Rate Sensor

One of the most important systems on the modern car is the stability control system. This is designed to help prevent rollovers, and is tied into the traction control system. One of the most vital components of your stability system is the yaw rate sensor, which is also called a rotational speed sensor.Its function is relatively straightforward – it measures a vehicle’s angular velocity on its vertical axis. Simply stated, it measures how far your vehicle is tilting in a turn. Information from your yaw rate sensor is delivered to the car’s computer, where it is used to determine if too much yaw is present. If too much yaw is detected, the computer can automatically apply the right braking pressure to one or more wheels, or adjusting engine performance to correct the problem. This makes sure your vehicle continues travelling in the direction you point the steering wheel.