What to Do When Your MAP Sensor Starts to Fail

27 May 2020
 Categories: Automotive, Blog


In days when life was a lot simpler, engine tuners would rely on their experience, a good sense of hearing and, often, a gut feeling. After all, they would need to make fine adjustments to achieve the best level of performance and had very little help from electronics. Today, however, the situation is very different, and the vehicle's ECM system will handle most of the work. Yet things can still go wrong and it may be more difficult to get to the bottom of it. If you're experiencing a range of performance issues, could the MAP sensor be at fault?

Balancing Pressure

For the engine control management system to keep everything in order, several sensors will need to transmit crucial data so that the adjustments can be made. One of these sensors helps to determine the air-to-fuel mixture when it enters each combustion chamber. To do this, it needs to know the absolute pressure at the manifold in relation to atmospheric pressure at any given moment (as this does change based on proximity to sea level). It will then send this information to the ECM, and the fuel injection system will be mapped accordingly, while adjustments are made to the spark.

Sensor at Work

When the vehicle is in motion, the sensor will send data to the ECU on a continual basis so that the engine will always receive the correct mixture. If the sensor begins to malfunction, however, many different problems can arise.

Sometimes, the sensor will succumb to heat damage or may become contaminated or clogged by dirt. The vacuum lines that connect the sensor to the manifold may crack, and this will generate false readings.

For example, the sensor may determine that the airflow is too low for the given situation and will inadvertently enrich the mixture. This may make it difficult to start the vehicle in the morning. Alternatively, the driver may find it difficult to overtake a slower car or truck because the ECM has restricted the mixture, once again based on incorrect readings from the MAP sensor.

Replacement Time

This sensor is one of many found within the engine bay, but it is nevertheless one of the most important. If it starts to play up, you will need to replace it quickly, but always make sure that you use the highest quality components.

To learn more about your options, contact companies like Bosch-authorised dealers in your area.