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How you can check, if your MAF is really broken
“How can I check if my airflow meter is broken?” It’s one of the most common questions we are being asked.
Right upfront – unfortunately there is hardly a 100% safe method. Therefore you can never be completely sure, but there are several approaches.
First of all you should summarize the symptoms to get to the bottom of the error:
- Bad engine performance:
The engine speed starts to fluctuate in idle speed (chainsaws). Sometimes the engine even dies off in idle, especially at railroad crossings or at crossroads an exciting story is guaranteed. - Increased fuel consumption:
Fuel consumption usually increases with a dirty or defective air flow meter, because the control unit no longer injects the optimum amount of fuel. - Low power
The engine has a low performance power. The maximum speed is reached very reluctantly or not at all. Often the car also has problems with acceleration. - Engine light illuminates
The check engine light in your cockpit is often turned on to show that the engine is having troubles.
- All these can be signs of a defective LMM – but they don’t have to be. Cars with a defective air flow meter do not always show these symptoms.
How do I test if the MAF sensor is broken?
One way to check it, is to remove the electrical connectors from your air flow meter. When there is no change at all and the motor continues to show a bad performance, the chances are high, that the MAF is broken.
And of course you can install a new or borrowed MAF and see, if the performance has improved. But since the motor often continues to run in a fail-safe modus, the ECU might not recognize the new part immediately and continues to run as if the MAF sensor is broken.
“I am seriously concerned… The symptoms suggest a faulty airflow sensor!”
A further step to find out the cause of the error is to read out the error memory.
Reading the error memory – Error code “Air flow meter”
In most cases the ECU recognizes that the values of the defective air flow meter are incorrect and stores a corresponding error in the error memory. In addition, the engine control lamp informs the driver that he should read out the error memory.
However, since the MAF is often not suddenly defective, but rather becomes insidiously dirty, the control unit does not always recognize the error. So it can happen that the MAF is defective without an error being stored in the error memory.
If an error can be detected out, it usually reads like this or something similar (every manufacturer has his own descriptions):
– “mixture too lean”
– “mixture too rich”
– “MAF defective”
If the error memory and the symptoms indicate that the MAF is defective, then this is most likely the case. But if you are ready to dig deeper, we recommend our blog article https://maf-shop.com/diagnostics-its-more-than-just-pulling-codes/
But what should you do, if the air flow sensor is indeed broken? Cleaning the air mass sensor might help, especially with hot wire sensors, but is usually only a short-term solution. Therefore, there is hardly any way around replacement. We all know the best air mass sensor shop 😉