Bad Map Sensor Indicators

Updated February 21, 2017

MAP sensor is actually the short name for the Manifold absolute pressure system sensor. The MAP sensor in your car or truck is used to tell the vehicle's computer how much pressure is in the intake manifold at any given point in time. Too much pressure inside an engine's intake manifold can cause a variety of problems and malfunctions in the vehicle, so it is important the MAP sensor in your vehicle operate properly. If you believe your MAP sensor is not functioning correctly, you should take your vehicle to a mechanic for a professional diagnosis and repairs.

Runs Poorly

The manifold air pressure sensor is one of the sensors that contributes to how the vehicle's computer tells the engine to balance the fuel and air mixture that powers the vehicle. If the fuel-air mixture is too rich or too lean, it will affect the way your vehicle runs. Your car may cough, sputter, idle poorly or consume a significantly increased amount of fuel if your MAP sensor fails.

Check Engine Light

Problems with your MAP sensor will cause your vehicle's check engine light to come on, though it may only come on occasionally or turn off and on inconsistently. The MAP sensor may be at fault if you notice the check engine light comes on only when the engine is under pressure.

Increased Exhaust

When a vehicle is running poorly and using too much fuel, it emits a lot more exhaust. The reason for this is that the fuel is not being used by the engine, it is simply running through it and coming out the tailpipe. Increased emissions are one of the signs of a bad MAP sensor.

Poor Acceleration

The MAP sensor controls the vehicle's vacuum and measures engine load so the computer can adjust the timing as needed. If the engine load is not being measured correctly, your vehicle may not accelerate well and the check engine light may flash on during acceleration.

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About the Author

Jen Davis has been writing since 2004. She has served as a newspaper reporter and her freelance articles have appeared in magazines such as "Horses Incorporated," "The Paisley Pony" and "Alabama Living." Davis earned her Bachelor of Arts in communication with a concentration in journalism from Berry College in Rome, Ga.