How to check mass airflow sensor
 

Is there anyway to check whether the mass
air flow sensor on a 98 E320 is working correctly.
I hate to go out and buy one and found out later
it is the O2 sensors that are bad.
I have a check engine on and using a OBD II scanner,
the code is Trim Fuel malfunction.
Thanks

If the codes are P0 170 & OR P0 173 then only fuel pressure, vacuum leaks or air mass sensor will cause this!

If your scanner will allow you to veiw LIVE DATA then you can see air mass values.

It is indeed P0170 & P0173. What should the value be and
what should I look for? thanks alot

I would bet money on the mass air meter if there are no vacuum leaks.

In actual values look at the partial load correction factor, if the value is above 1.25 then the air mass sensor is to blame.