What Are MAP Sensors And What Happens When They Fail?
The MAP sensor’s job is to monitor the air that flows into the engine.
If your car starts burning too much fuel or running roughly, it can be frustrating trying to determine the cause, especially if there aren’t any other issues that pop up at the same time. That can be the case with issues stemming from your vehicle’s MAP sensor, but there’s a decent chance that the part isn’t at the top of your bucket of automotive knowledge.
To be frank, Car Bibles’ editors don’t think about MAP sensors a whole lot, either, but we have spent plenty of time diagnosing and replacing them, and in that experience, we’ve accumulated knowledge we’d like to share with you. Although it can be stressful not knowing what’s going on under your hood, we’re here to help you get your project started down the right path.
What Is a MAP Sensor?
Your car’s MAP sensor won’t help you find your destination or yell at you when you miss a turn. MAP stands for manifold absolute pressure, and the MAP sensor’s job is to monitor the air that flows into the engine. This allows the vehicle’s computer to tinker with ignition timing, work out air density, and adjust fuel delivery. You may hear the term MAF sensor, which stands for mass airflow sensor. Although similar, MAF sensors monitor air flow instead of air density.
What Happens When The MAP Sensor Starts To Fail?
Because the MAP sensor deals with air and fuel flow, any disruption in its ability to properly monitor the situation can lead to a rough running vehicle. If fuel flow is too strong, you may notice poor fuel economy, but the opposite can happen when the sensor believes less fuel is needed.
You may also experience misfires or detonation, which is when fuel spontaneously combusts in the cylinder at a time other than when the spark plug fires. Just to stress you out a little more, you’ll probably see a check engine light as well. Common error codes when this happens are P0068, P0069, P1106, and P1107.
What Causes MAP Sensors To Fail?
The sensor is composed of both electrical and mechanical components, both of which can cause problems over time. Part of the sensor is formed by a vacuum chamber, which can leak and cause issues. The sensor may also experience issues because of vibrations, heat, and road dirt over time.
How Much Does a Replacement MAP Sensor Cost?
There’s good news here, because MAP sensor replacement won’t break the bank. In most cases, the sensor should be able to be replaced for $200 or less. The part itself makes up most of that cost, at up to $175 or more.
You ask, Car Bibles answers!
Q: How Hard Is It To Change The MAP Sensor Myself?
A: In most cases, you should be able to change out the sensor yourself with a few basic tools and a half-hour or so of free time. The sensor is usually located on the outside of the intake manifold or throttle body. Check your vehicle’s maintenance manual to find its specific location.
Q: Can I Drive With a Broken MAP Sensor?
A: Although it might be possible to drive with a bad MAP sensor, it’s certainly not a good idea. Beyond the inconvenience and expense of burning too much fuel, having a vehicle that isn’t running right, or one that stops running altogether, is both dangerous and a big hassle. You also run the possibility of further damaging your engine.
Q: Can I Test Just The Sensor Itself?
A: You absolutely can. You’ll need a multimeter and a half-hour or so of time. Make sure you’re comfortable working with the battery and reading the voltage tool. In some cases, it’s just as easy to replace the sensor.
Q: Will I Always See A Check Engine Light?
A: Nope! You might not see a check engine light, but the telltale signs of a MAP sensor failure may still be present. Don’t rely on the stressful old CEL to let you know when things are going bad.
The Video Tutorial on MAP Sensors
The Tools and Parts To Buy For The MAP Sensor
Diagnosing and fixing your car’s MAP sensor can be tricky if you’re not an experienced wrencher. That’s why Car Bibles’ editors have selected a few of their favorite products to help get you started on the right foot. They include the Innova CarScan Pro 5210, Mechanix Work Gloves, and Dewalt Clear Safety Goggles.
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