How to Clean Mass Air Flow Sensor
 

My check engine light is on in my 1998 ML320.
As I understand it, the following codes
P0170 Fuel Trim Malfunction (bank 1)
P0173 Fuel Trim Malfunction (bank 2)
indicate a problem with the Mass Air Flow sensor.
I would like to try cleaning it.
Could I do it this way:
Open up the air cleaner.
Discard old air filter.
Clean out the interior with a wet cloth.
Start engine.
Spray Mass Air Flow Cleaner into air intake.
Install new air filter.

I had the same problem on my 2001 SLK. I removed the MAF and sprayed it with MAF cleaner, re-installed it and cleared the codes. No problems since.

I think you should remove the MAF to clean it.

You have to remove the MAF insert from the plastic housing. You will need torx security bits for this. Spray the wire in the insert with CRC MAF cleaner. I assume that you are reinstalling or getting a new air filter if needed.

As Michael mentioned you'll need to remove the insert. Let it dry before assembling everything.

Unfortunately this is probably just a temporary fix. It will work great for a couple of months but most people's experience is that the sensor is on its way out. You should think about just buying a new one. It's pretty cheap.

Hopefully you've been around and know not to buy the parts off of ebay. For the most part they are all scams.

Scam ?
 

I tryed cleaning my MASS no luck.
Bought one on Ebay over a year ago, it was cheap and worked fine.

I dont think most Sensors are bad on Ebay. Check the sellers rating.

Others have had problems with the ebay MAFs though. It is safer just to get it from ********az or germanstar.