SYMPTOMS OF A BAD MAP SENSOR
purpose
The purpose of the MAP sensor is to provide manifold pressure to the ECM. The engine control module then uses this information to produce the perfect air-fuel ratio of 14.7 (air) to 1 (gasoline). With that being said, if the ECM reads more air coming in, it’s going to command more fuel. If it reads less air coming in, it’s going to command less fuel.
The MAP sensor's location will be on the intake manifold, typically right after the throttle.
Note: you might not have a MAP sensor. Your vehicle might be equipped with a MAF sensor. If so, click here to view the symptoms of a bad MAF sensor.
The average life expectancy of a MAP sensor is typically from 125,000 to 150,000 miles.
SYMPTOMS
engine light
The first symptom of a bad MAP sensor is having a check engine light on. Here are some codes related to a bad MAP sensor:
P0105
P0106
P0107
P0108
P0109
Ensure you can access your car's diagnostic codes by acquiring an OBD2 scanner here.
It’s important to remember that you can still have a faulty MAP sensor with no check engine light on, so let’s move on to the next symptom.
engine stalling
The second symptom of a faulty MAP sensor is your engine stalling. Imagine, you turn on your car, start listening to some music, and a minute later your car suddenly turns off. For example, if the MAP sensor tells the ECM it reads less air coming in, then the ECM is going to produce less fuel. But a good working MAP sensor should be reading more air coming in. So there should be more fuel being added. This leads to more air than fuel ratio, which results in no combustion. That’s why you’re experiencing your engine stalling.
misfire
The third symptom you can be experiencing is a misfire. The same reason would apply here as in the previous symptom. More air than fuel ratio would lead to no combustion, which is going to create an engine misfire.
reduced power
The fourth symptom of a bad MAP sensor is reduced engine power. You’re driving down the road and trying to accelerate, but the power isn’t there. This all comes back to the fuel not being burned efficiently. In order for the engine to run as smoothly as possible, the air-fuel ratio has to be the best that it can be.
no start
The fifth symptom of a bad MAP sensor could be a no-start. If the reading is bad and there’s more air and less fuel coming in, it’s going to prevent the combustion from occurring. That’s why you may be experiencing a no-start.
Rough idle
The sixth symptom you can be experiencing is a rough idle. Let’s say, the air-fuel ratio is not too bad to the point where it’s going to create a no-start. But it’s still bad enough to create a rough idle and a couple of misfires here and there.
bad fuel ecnomy
The seventh symptom of a bad MAP sensor could be a bad fuel economy. If the MAP sensor provides a bad reading of more air, the ECM is then going to want to provide more fuel. But the real reading should have been less air, so the ECM should have been providing less fuel. The final result came out to be less air and more fuel, leaving unburnt fuel in the cylinder. This is why you have to go to the gas station more often.
black smoke
The last symptom of a faulty MAP sensor is black smoke coming out of the exhaust pipe. Since there’s unburnt fuel in the cylinder, it gets kicked out to the exhaust where it gets burned and creates black smoke.
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