How do I clean the MAP sensor?

The MAP sensor, or boost pressure sensor, uses its resistors to measure intake air pressure. It is most commonly found on turbocharged diesel vehicles, but can also be found on some gasoline vehicles. Problems detected in the boost pressure sensor, also known as the "MAP sensor" for "Manifold Absolute Pressure," are often due to contamination. Defects can be corrected by proper cleaning. Read this article to learn how to clean it.

Malfunction Symptoms

A MAP sensor can become clogged, damaged, or contaminated. Sometimes excessive heat from the engine can damage it or the vacuum lines. If it's not working properly, the ECU can't accurately calculate the air-fuel mixture, which means it's either too rich or too lean. Here are some symptoms of a bad MAP sensor

• ESP warning light on the dashboard with a key.
• The cruise control and speed limiter not working.
• Very high idle, stuck at ~1150RPM even when warm.
• Full throttle impossible at the bottom of the pedal.
• Air conditioning not working.
• Engine power limited.

Sensor failure generates an OBD error code that may not be readable by all applications. The clear command, even if the code is not visible, seems to work perfectly and will solve the problem if the lights remain on after the intervention.

Cleaning the MAP Sensor

Cleaning the MAP sensor is sometimes necessary when it becomes too clogged and interferes with your car's fuel injection. In this case, you will need to access the sensor, disassemble it, and clean it with a special product. Be careful not to disassemble the car's turbo.

• Step 1: Wear rubber gloves and safety glasses.
• Step 2: Remove the MAP sensor. Check your service manual for the location of the MAP sensor. It's usually located in or near the intake manifold. Once you've located it, disassemble it by removing the connector and its plug. Then unscrew the screws holding the MAP sensor in place and remove it.
• Step 3: Use a paper towel or soft cloth and an electrical parts cleaner to remove any dirt from the sensor. Place the MAP sensor on a flat surface, facing up. Rub the sensor with the cloth soaked in the electrical parts cleaner, being careful not to rub the sensitive parts of the sensor.
• Step 4: Spray the cleaner inside - a few sprays are sufficient. If necessary, spray the Electro Cleaner lightly on parts that cannot be reached with the cloth.  
• Step 5: Shake off excess cleaner and allow to dry completely.
• Step 6: Check the suction pipe or intake manifold hole for additional debris. If you see more dirt or debris, clean the hose with the same product and a brush.
• Step 7: Allow the sensor to dry for a few minutes. When everything is dry, it should be clean.
• Step 8: Once dry, reinstall.

How do I choose the right electrical contact cleaner?

You'll need to decide what you mean by cleaning, the type of contamination you want to remove, the function of the component you're cleaning, and so on.

A mixture of demineralized water, alcohol, and ether works well to remove accumulations of dust, grease, etc. from electronic circuit boards; you must supplement the product with mechanical action, brushing or otherwise, and proceed in several stages so that the last traces are removed by the final rinse. In general, electronic components are resistant to these products, but there may be exceptions, so always use common sense and caution. Use a compressed air gun for final drying.

Depending on the type of contamination, you may need to adjust the formula or even eliminate one of the ingredients.

For alcohol, choose ethanol or propanol; avoid methanol.

If the stains are mainly greasy, omit the water; if they are greasy and stubborn, a "mild" organochlorine such as chlorothene can be used, but with great caution, as it also attacks certain plastics.

For moving contacts, connectors, etc., avoid certain products that do not evaporate; prefer products that evaporate completely, such as propanol, and rub with a soft cloth. In the case of infrequently used connectors without power (antennas, etc.) or "signal" contacts, Vaseline can be sprayed on after cleaning to prevent further oxidation; never use on power.