Dic P0101 What To Do

[TODD L GRIFFITH]

PO101, is the Mass Air Flow Sensor Circuit Performance Out of Range code. This will trigger a check engine light. The symptoms are running extremely rich one minute and extremely lean the next. These conditions were monitored, checking the short term fuel trims with a Diablosport Predator, cruising down the highway +/- 2000 rpm or 80mph. Range rich -33.00%, Range Lean +10.00%

You may get two other codes associated with P0101.
1. P0172 Fuel Trim System Rich Bank 1 O2 sensor >Duh?
2. PO175 Fuel Trim System Rich Bank 2 O2 sensor >Duh?

The last resort should be to replace the MAF. After doing some online reading, I narrowed the problem to one of the three MAF sensor elements. Being extremely sensitive, these elements need to be clean. Hotwire type elements flow air over the element then convert heat loss or gain to a voltage, that is sent to the PCM, to control the air fuel mixture based on the incoming air temperature and velocity over the wire. (very sensitive)

Fix:
When I removed the MAF, I found that one of the elements was dirty. I carefully used a cotton swab soaked in acetone, and gently cleaned the element. Clean the other two elements, seeing you have the MAF removed anyway. Be very careful!

Cleaning solutions can be a throttlebody cleaner, or acetone like I used, for its high evaporation rate.

After reinstallation, drove it to work, monitored fuel trims, no codes. The car ran beautifully all day.

Cause:
I believe the cause was that oil from the crank case ventilation tube mounted on the air filter, managed to find its way to the element due to its proximity to the MAF.

Also, beware of over oiling your K&N. This can affect the elements also if the filter oil finds its way on to the elements.

 

[BlackZ28Turbo]

Thanks for the tip. This is great information.

 

[TODD L GRIFFITH]

Your welcome BlackZ28Turbo, I know for sure, some people have gone out and purchased new MAF sensors which solved the problem, only to have the codes reappear after some heavy driving. If they checked and cleaned the elements on their old one, it would have saved them a few hundred dollars. What I like best about this thread is that someone that gets a PO101 code, can just do a search for "PO101" and get a fix, or something to go on, right here at the CAC. A vacuum leak, or a plugged EGR valve, can also throw a PO101 code. I hope this will help someone in the future.

 

[DRTH VTR]

I read a thread either here or Corvettemechanic that talked about excessive oiling of K&N (or similar) causing problems with the MAF.

 

[TODD L GRIFFITH]

Yes DRTHVTR, it can really be a problem for the MAF. If there is a spec of oil on the element(s) the MAF will not be able to accurately read the incoming air at all. It's amaizing how sensitive they are. The elements have to be dry and totally clean. After a visual inspection of my elements, it was obvious which one it was. I cleaned them all anyway.