The Nissan Micra suddenly loses power while driving. This problem mainly occurs at higher speeds. The cause is often a faulty mass airflow sensor (a component that measures the amount of air going to the engine). This sensor sends incorrect readings to the engine. Fortunately, you can solve this problem by replacing the sensor. Read on to find out how to recognise and tackle this issue.
Why does the Nissan Micra suddenly lose power?
You are driving and notice that your car suddenly delivers less power. This can have several causes. In the Nissan Micra this symptom often points to a problem with the mass airflow sensor, also called the MAF sensor. MAF stands for “mass airflow” and this component measures the amount of air entering the engine. The sensor sends this information to the engine control unit.
The engine control unit receives this data and uses it to calculate the correct amount of fuel. When the MAF sensor fails, the engine then gets incorrect information. As a result, the system mixes too much or too little fuel with the air. The result: your car loses power, especially when you need it on the motorway.
‘ The engine control unit then limits the power to prevent damage. ’
Symptoms that point to a faulty MAF sensor
A faulty mass airflow sensor causes recognisable problems. You usually will not notice immediately that something is wrong during gentle city driving, but as soon as you ask for more power, the problems start. These are the most common signs:
- Sudden loss of power while accelerating
- Engine hesitation at higher speeds
- Irregular engine idle speed when stationary
- Increased fuel consumption without any clear reason
- Engine warning light coming on
- Poor throttle response
Some owners report that the car temporarily switches to limp mode. The engine control unit then limits the power to prevent damage. You can usually still drive, but the car feels sluggish and responds poorly to the accelerator pedal.
How the MAF sensor works in your Nissan Micra
The mass airflow sensor is located between the air filter and the engine. It is a sensitive component that constantly measures the airflow. In most Nissan Micra models the sensor uses a heated wire or film. The airflow cools this down and from the degree of cooling the sensor calculates how much air is passing by.
Due to contamination, oil or dust, the sensor can become less accurate over time. Vibrations and temperature changes also affect the sensitive electronics. In older Micras, especially models with higher mileage, this problem occurs regularly.
Testing the MAF sensor yourself
You can fairly easily check whether the MAF sensor is causing the problem. First have a diagnosis carried out with an OBD2 scanner (a device that reads the car’s fault codes). This reads out the fault codes that the engine control unit has stored. Codes that point to MAF problems often start with P0100 to P0104.
A practical test is to temporarily disconnect the sensor. Start the engine with the MAF sensor disconnected and drive a short distance. The engine control unit will then switch to default values. Does the car drive better without the sensor? If so, there is a good chance that the MAF sensor is faulty.
Note: this test does not work equally well on all models. Some Micras will not start or will run very irregularly without the sensor connected. Therefore carry out this test carefully and only drive in a safe location.
‘ Do not use ordinary cleaning agents, as these can further damage the sensitive element. ’
Visual inspection of the sensor
Open the bonnet and locate the MAF sensor. It is usually located directly behind the air filter in the intake hose. Disconnect the sensor by carefully removing the electrical connector. Check whether you see any dirt, oil or damage on the measuring element.
Sometimes you can clean the sensor with a special MAF cleaner spray. Spray gently onto the measuring element and allow it to dry before refitting the sensor. Do not use ordinary cleaning agents, as these can further damage the sensitive element.
When replacement is necessary
Cleaning does not help, or the sensor is visibly damaged. In that case you must replace the component. In cases of persistent power loss that is not resolved by cleaning, it is better to opt straight away for a new sensor. This prevents you from wasting time and money on a temporary solution.
Owners report that the problem is usually resolved immediately after replacement. The engine responds normally again, the power returns and fuel consumption goes back to normal. The engine warning light often goes out by itself after the car has been driven for a while with the new sensor.
Costs of replacing the MAF sensor
The price of a new mass airflow sensor for the Nissan Micra varies between 80 and 200 euros. Genuine Nissan sensors are more expensive than alternative brands. If you opt for a cheaper sensor, always check that it is suitable for your specific Micra model and year of manufacture.
Labour time for replacement is usually between half an hour and one hour. At a garage you will often pay between 150 and 300 euros in total including labour. The exact price depends on your region, the type of sensor and the garage’s hourly rate.
Do you have technical knowledge and tools? Then you can also replace the sensor yourself, which saves labour costs. For most Micra models you only need a screwdriver. The sensor is usually secured with two screws and has one electrical connector.
‘ Sometimes you have to drive a short distance first before the engine control unit adapts to the new sensor. ’
Steps for replacing it yourself
This is how you replace the MAF sensor: first switch off the engine and open the bonnet. Locate the sensor in the intake hose between the air filter and the engine. Disconnect the electrical connector by pressing the clip.
Then loosen the mounting screws. These are usually two small screws. Carefully pull the sensor out of the intake hose. Fit the new sensor in reverse order. Make sure the rubber seal is properly in place and do not overtighten the screws.
Reconnect the electrical connector until you hear a click. Start the engine and check whether the engine warning light goes out. Sometimes you have to drive a short distance first before the engine control unit adapts to the new sensor.
Other possible causes of power loss
Although a faulty MAF sensor is often the culprit, other problems can also cause power loss. Therefore also check these components if replacing the sensor does not help:
- Clogged air filter that restricts airflow
- Faulty ignition coil or spark plugs causing ignition problems
- Clogged fuel filter that restricts fuel supply
- Leaking intake hoses that allow unmetered air in
- Problems with the turbo on turbocharged engines
For persistent problems, professional diagnosis is recommended. A garage can use specialist equipment to identify the exact cause, which prevents you from replacing parts unnecessarily.
Prevention and maintenance
Good maintenance extends the life of the MAF sensor. Replace the air filter according to Nissan’s service schedule. A clean air filter blocks dirt that could otherwise damage the sensor. Regularly check that the intake hoses are properly secured and are not split anywhere.
Use quality fuel and occasionally drive a longer distance at higher speed. This helps to reduce deposits in the intake system. During services, also have the sensor visually checked for contamination.
On the Carnews website you will find much more information about maintenance and problems with different car makes and models. Discover useful tips, spot symptoms earlier and learn how to carry out simple repairs yourself. Also check out the other articles about the Nissan Micra and similar models for more practical knowledge.
Frequently asked questions
Yes, power loss definitely affects the driving experience and dynamics of a Nissan Micra, particularly noticeable when accelerating, overtaking and driving at higher speeds. The car then responds more slowly to the accelerator, feels less lively and may struggle to maintain speed on inclines. As a car enthusiast you will also notice that the engine sound and the way the revs build up no longer match the actual acceleration. This takes away the enjoyment of precisely modulating the throttle and the ‘connection’ you feel with the car.