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Sensors

Sensors
Short & Sweet
sensors

mass air flow sensor

  • Coolant Temperature Sensor – Monitors the temperature of your coolant.
  • Mass Air Flow Sensor – Measures the mass of the air flowing into your engine. The computer uses this information to determine the amount of fuel to put into your engine.
  • Oxygen Sensor – Measures the amount of oxygen flowing through the exhaust. For example, if your engine is running lean (meaning there is too much oxygen to fuel ratio), it will tell the computer to put more fuel into your engine.
  • Crank Shaft Position Sensor – Monitors the rate to which your engine is turning over. This sensor tells your tachometer (rpm gauge) what to say. RPM stands for revolutions per minute.

Symptoms of Failure:

  • Coolant Temperature Sensor

*Your check engine light will come on.
*Your temperature gauge will most likely show the engine temperature as very hot or very cold.

  • Mass Air Flow Sensor

*Your check engine light will come on.
*Your gas mileage may have decreased.

  • Oxygen Sensor

*Your check engine light will come on.
*Your gas mileage may have decreased.
*In very rare cases, a bad oxygen sensor could damage your engine’s computer, causing your engine not to run.

  • Crank Shaft Position Sensor

*Your check engine light will come on.
*Typically your car won’t start, and it may quit running.  If the crank shaft position sensor has a problem and tells your engine computer that the crank shaft is   not turning, your car is going to stop or not start.

Care & Repair:

If your check engine light comes on and you get a diagnostic reading indicating a sensor problem, a sensor gave a signal back to the computer telling it that something is wrong.  There are four things that could actually be wrong:  the sensor itself, the wiring, the computer, or a problem with another part on your car. For example, your coolant temperature sensor could be telling your computer that there is a problem and it could be an issue with your water pump or thermostat, not the sensor, wiring, or computer.

If you find that there is a problem with an actual sensor, it will most likely need to be replaced. In rare cases, a mass air flow sensor can be cleaned.

Coolant temperature sensors and mass air flow sensors often get replaced unnecessarily. If you get a diagnostic on your car and a reading comes back saying, “mass air flow reading low,” the cheapest and easiest fix might be to start with replacing the sensor, when the actual problem could be something else. Just be aware of this and make sure that you are taking your car to a thorough technician.

Cost:

To get an estimate on how much replacing a sensor will be for your specific car in your part of the country, go to www.repairpal.com

Purpose
  • Coolant Temperature Sensor – Monitors the temperature of your coolant.
  • Mass Air Flow Sensor – Measures the mass of the air flowing into your engine. The computer uses this information to determine the amount of fuel to put into your engine.
  • Oxygen Sensor – Measures the amount of oxygen flowing through the exhaust. For example, if your engine is running lean (meaning there is too much oxygen to fuel ratio), it will tell the computer to put more fuel into your engine.
  • Crank Shaft Position Sensor – Monitors the rate to which your engine is turning over. This sensor tells your tachometer (rpm gauge) what to say. RPM stands for revolutions per minute.
Symptoms
  • Coolant Temperature Sensor

*Your check engine light will come on.
*Your temperature gauge will most likely show the engine temperature as very hot or very cold.

  • Mass Air Flow Sensor

*Your check engine light will come on.
*Your gas mileage may have decreased.

  • Oxygen Sensor

*Your check engine light will come on.
*Your gas mileage may have decreased.
*In very rare cases, a bad oxygen sensor could damage your engine’s computer, causing your engine not to run.

  • Crank Shaft Position Sensor

*Your check engine light will come on.
*Typically your car won’t start, and it may quit running.  If the crank shaft position sensor has a problem and tells your engine computer that the crank shaft is   not turning, your car is going to stop or not start.

Care & Repair

If your check engine light comes on and you get a diagnostic reading indicating a sensor problem, a sensor gave a signal back to the computer telling it that something is wrong.  There are four things that could actually be wrong:  the sensor itself, the wiring, the computer, or a problem with another part on your car. For example, your coolant temperature sensor could be telling your computer that there is a problem and it could be an issue with your water pump or thermostat, not the sensor, wiring, or computer.

If you find that there is a problem with an actual sensor, it will most likely need to be replaced. In rare cases, a mass air flow sensor can be cleaned.

Coolant temperature sensors and mass air flow sensors often get replaced unnecessarily. If you get a diagnostic on your car and a reading comes back saying, “mass air flow reading low,” the cheapest and easiest fix might be to start with replacing the sensor, when the actual problem could be something else. Just be aware of this and make sure that you are taking your car to a thorough technician.

Cost

To get an estimate on how much replacing a sensor will be for your specific car in your part of the country, go to www.repairpal.com

 

About The Author

Pedals and Pumps

PedalsandPumps provides direct, honest information about car maintenance and repair. We provide money and time saving tips for readers who want to maximize their dollar and simplify their auto owning experience.

TIP:

If you have lost a cap on your tire inflation valve, mention it at your next oil change and the technician will probably replace it for your for free. More ways to tell if you have a tire pressure issue.

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