Your Guide to Map Sensor Cleaning

Your vehicle’s manifold absolute pressure or MAP sensor is one of the sensors needed by the electronic control system of an internal combustion engine. Fuel injection is common in engines that use a MAP sensor. Dust, dirt, filth, carbon, and oil build up inside and outside engines, causing problems. MAP sensor cleaning may be required if you're having poor fuel economy, a rough idle, hesitation or stalling when accelerating, or an illuminated check engine light.  MAP sensor cleaning is a simple approach to improve engine performance and efficiency.

A manifold absolute pressure (MAP) sensor is used in fuel-injected vehicle engines to continually monitor the quantity of air flowing into the engine so that the computer can calculate air density, modify the amount of fuel sprayed into the combustion chamber, and adjust ignition timing. A mass air flow (MAF) sensor is utilized in various cars. A MAF sensor, while interchangeable with a density sensor, monitors flow rather than density.

A faulty MAP sensor can cause a variety of performance issues in your car. If the sensor is malfunctioning and reading too high, the fuel management system will consume more fuel than necessary, reducing fuel economy. If the MAP sensor reads too low, the onboard computer will reduce the amount of gasoline it believes the engine requires, starving it and causing it to run erratically and lose power. If the sensor isn't reading correctly in either situation, your car will fail emissions testing.

A MAP sensor failure can be caused by a variety of circumstances. The sensor's ability to read changes in manifold pressure is due to a vacuum chamber inside the sensor. A leak in the vacuum chamber might develop over time, rendering the sensor useless. Years of significant temperature swings and vibration can also wreak havoc on the internal circuitry due to the sensor's location in the harsh engine compartment environment. Another point of failure is when dirt or other contamination prevents the sensor from directly contacting the intake manifold air flow. So if you are lucky a simple map sensor cleaning is all you need to get things back in good working order.

What are the symptoms of a dirty MAP sensor?

A faulty MAP sensor can have major consequences for fuel control, vehicle emissions, and fuel economy. The following are signs of a defective or failing MAP sensor and it might be time for map sensor cleaning or worse repair or replacement.

1. Check Engine Light

The engine computer will send out a diagnostic code, prompting the “Check Engine” light to illuminate, which is the most evident indication of a defective MAP sensor. Most cars built after the 1990s can be connected to a diagnostic gadget known as a “code reader,” which displays the codes and interprets the underlying causes. Some cars can show these codes without the use of a code reader if certain steps are followed, but this will only result in a numeric number that must be looked up. However, an engine code might occasionally mistakenly imply a defective MAP sensor.

1. Excessive fuel consumption

A MAP sensor that detects high intake manifold pressure alerts the PCM to a high engine load. As a result, the amount of fuel pumped into the engine increases. As a result, your total fuel economy suffers. It also increases the quantity of hydrocarbon and carbon monoxide emissions released into the atmosphere by your vehicle. Some of the chemical components of smog include hydrocarbons and carbon monoxide.

1. Lack of power

A MAP sensor that detects low intake manifold pressure informs the PCM of low engine load. In response, the PCM reduces the amount of fuel injected into the engine. While you may notice a boost in fuel economy, you'll also notice that your engine isn't quite as strong as it once was. The temperature of the combustion chamber rises as the amount of fuel in the engine is reduced. This raises the amount of NOx (nitrogen oxides) produced by the engine. Smog also contains NOx as a chemical component.

1. Engine Surging

The air intake and the discharge of gasoline from the fuel injectors may be out of sync due to a defective MAP sensor. A common symptom of this condition is a delayed acceleration followed by a sudden spike.

1. Fouled Spark Plugs

If the engine's air flow isn't properly regulated, it will run “lean” or “rich” on a regular basis. This relates to how well the engine performs when the fuel burns with too much or too little oxygen. An engine operating “lean” will have diminished horsepower, whereas an engine running “rich” will be clear from a spark plug inspection. The spark plugs will become fouled, which means that residue from poor combustion will coat them.

1. Gas Smell Coming From The Exhaust Pipe

The gas smell coming from the exhaust is another direct result of a faulty MAP. Fuel particles streaming through the exhaust system is a common problem when combustion is not completed in the chamber.

This symptom is more delicate than you might believe, so don't dismiss it. Aside from the odor and possibly smoke from the exhaust, the catalytic converters may be irreversibly damaged, as liquid particles such as unburned fuel are extremely damaging to catalytic converters.

1. Failed emissions test

Before a vehicle's registration may be renewed, many jurisdictions require it to pass emissions tests. If the vehicle is emitting excessive amounts of pollution and all other possibilities have been ruled out, the problem could be a defective MAP sensor.

Your car will fail an emissions test if the MAP sensor is defective. Your exhaust emissions may contain a lot of hydrocarbons, a lot of nitrogen oxide NOx, a lot of CO2, and a lot of carbon monoxide. A professionally educated technician can diagnose and fix a malfunctioning MAP sensor.

How to Check if You Need Map Sensor Cleaning

A vacuum pump and a multimeter are all you need to test a MAP sensor. Remove the MAP sensor or the vacuum line from the intake manifold first. Check the voltage output on the MAP sensor signal line with the MAP sensor connected and the ignition in the “on” or “run” position. Engines with turbocharger MAP sensors respond to pressure as well, albeit their pressure/voltage values may differ. Check your repair manual for a wiring schematic and particular voltage readings in either case.

When exposed to the air, a typical MAP sensor should measure around 4.7 V. At 20 inHg vacuum, the voltage should drop to roughly 1 V using the vacuum pump. Repeat the test, noting that the voltage should respond promptly as you draw and release vacuum/pressure.

Although MAP sensors don't have any moving components and don't normally wear out, they may need to be cleaned if they've been polluted by carbon or other engine deposits. Contamination could be at blame if voltage is slow to respond to pressure changes.

Map Sensor Cleaning Procedure

Map sensor cleaning is easy when following a few guided steps not only to be able to do it properly but also safely.

1. First and foremost, allow the engine to cool by parking it in a flat area. While the engine is turned off, unplug the battery before working on your car. Find a flat location to park your car on and wait 5 minutes for the engine to cool. After that, open your car's hood. To be safe, avoid parking on an incline. After allowing the engine to cool, lightly touch it. Wait another 5 minutes or until it cools down if it's still heated.

1. To be safe, disconnect the automobile battery. On the top of the car battery, look for the negative terminal. A black cap is usually worn over it. If not, a “-” sign should be near or on top of the connector. Find the right wrench socket size for the nut on the negative terminal. Connect this socket to your wrench and crank it counterclockwise to remove the nut. Disconnect the negative battery cable after that. Replace the negative terminal with the positive terminal and repeat the procedure. It's usually covered with a red cap or has a “+” sign on it.

1. The MAP sensor should be near the intake manifold. The MAP sensor is usually located near the intake manifold in most autos. It should be connected to a group of wires using an electrical connector. A rubber vacuum hose will also be connected to it. Lift the engine's wiring harness slightly to get a clearer view if you're having difficulties finding it. Pull out the plastic ends of the wiring harness's cables to loosen it. Remove only the ones that make it easier to reach the MAP sensor.

1. Disconnect the MAP sensor's vacuum line. The retaining rings must be removed before the vacuum line can be removed. In the two holes on the ring, insert a pair of straight retaining ring pliers. To expand the ring and remove it from the vacuum, squeeze the pliers together. Remove the vacuum line from the MAP sensor once all of the rings have been removed.

1. Remove all of the fasteners that secure the sensor to your car. The sensor is normally held to the vehicle by two to three bolts. Remove them from the car by turning them counterclockwise with a socket wrench. Your sensor should then come loose. To avoid losing the bolts, store them in a compact plastic container.

1. Disconnect the MAP sensor's electrical connector. A clip is frequently used to connect the electrical sensor to the MAP sensor. The clip is usually unhooked by sliding it upward or downward. After that, remove the connector from the sensor while holding down the locking tab. If there isn't a clip, remove the electrical connector away from the MAP sensor by pressing on the locking tab.

1. Wear rubber gloves to protect your skin after detaching the MAP sensor connector. Safety glasses are also an excellent idea. Clean the outside of the MAP sensor with an electric parts cleaner and a soft rag or paper towel.

1. Spray a couple of spritzes of electric parts cleaner on to the sensor port. Shake out any excess cleaner and let it dry. Additional contamination can be found in the MAP sensor vacuum pipe or the intake manifold port. If necessary, clean these with an electric parts cleaner and a brush.

1. Place the MAP sensor upside down on a flat surface. Apply electrical parts cleaner on a dry rag. Scrub the rest of the sensor gently with the rag, being careful not to scratch the sensor. Spray cleaning solutions lightly into areas where the rag can't reach. But if at all possible, avoid doing this because you won't be able to scrub and dry it thoroughly.

1. The MAP sensor should be free of contamination once everything is dry, which shouldn't take long. Remove the MAP sensor and reinstall it. Drying your MAP sensor shouldn't take more than 5 minutes with thorough washing. After that, reconnect the electrical connector and screw the sensor back to the vehicle. Finally, reattach the retaining rings to the vacuum line. By opening the retaining rings with your retaining ring pliers and inserting them around the vacuum line, you can snap them back on. And the map sensor cleaning is done.

When should MAP sensor be replaced?

Unlike many other parts in your vehicle, you won't have to worry about replacing your MAP sensor very often, if at all. MAP sensors, in general, are built to survive for as long as you own your car. If you drive your car for more than 150,000 miles, it will ultimately break down.

How much does it cost to replace a MAP sensor?

This sensor is critical to the safe operation of your engine and the smooth operation of your vehicle. The cost of replacing a map sensor ranges from $130 to $200. Labor should cost around $14-$25, while parts should cost between $110 and $180. The price of a MAP sensor can vary depending on the brand and model of your vehicle. The price of a MAP sensor may rise or fall depending on your area. Even the type of engine in your automobile can influence the cost of a new MAP.