Anyone know how to test a MAS mass flow air sensor ? - PeachParts Mercedes-Benz Forum

sdanville · #1 12-20-2006, 01:35 PM

I replaced my MASS last month - 1) it has not adjusted the computer after 3 weeks or. 2) Has not cured my problem because it is defective.3) its not my problem.

I keep getting codes suggesting the MAS.

There is an Ebay seller that says he is a Mercedes Tech and sells used ones that are tested and referbished.
I asked him if referbished means "cleaned". He wrote he has a process where he brings them back to specifications. I asked him again, " So you clean them ? " He did not reply to my 2nd question.

I may have wasted some more money ordering a tested used one..should be here this week.
I have analog and digital electric test meters. Anyone know what to check on a MAS ?

Last week I checked my ignition wires on one bank but still do not know what specification they should be . if anyone knows that would help me rule out the wires. Replaced plugs two times in 10,000 miles and new cats.

Not hitting on 6 in Michigan.
steve

RAYMOND485 · #2 12-20-2006, 02:30 PM

2001 E320 47,000
Replace The 0-2 Sensor May Be $20.00 -$100.00 And Air Filter Diy
Pass Smog Test Super Clean If Fuel Mileage Is Low Replace Mass
Sensor $255.00 And 0-2 Sensor $100.00 Ea 2 Before Cat And 2 After. Replace The 2 Before Cat Special Socket Any Auto Store

sdanville · #3 12-20-2006, 03:34 PM

uh...
thanks, maybe I should replace a few hundred dollars of oxygen sensors too.

So, does anyone know how to test a Mass Air Flow Sensor ?

w163ml · #4 12-20-2006, 03:45 PM

Quote:

Originally Posted by sdanville

I replaced my MASS last month - 1) it has not adjusted the computer after 3 weeks or. 2) Has not cured my problem because it is defective.3) its not my problem.

I keep getting codes suggesting the MAS.

There is an Ebay seller that says he is a Mercedes Tech and sells used ones that are tested and referbished.
I asked him if referbished means "cleaned". He wrote he has a process where he brings them back to specifications. I asked him again, " So you clean them ? " He did not reply to my 2nd question.

I may have wasted some more money ordering a tested used one..should be here this week.
I have analog and digital electric test meters. Anyone know what to check on a MAS ?

Last week I checked my ignition wires on one bank but still do not know what specification they should be . if anyone knows that would help me rule out the wires. Replaced plugs two times in 10,000 miles and new cats.

Not hitting on 6 in Michigan.
steve

http://www.benzworld.org/forums/w163-m-class/1288422-mass-air.html

sdanville · #5 12-20-2006, 04:36 PM

thank you for the link
I was the 43rd post in that link. Thats back when I tried cleaning my MAF--before I bought a new one. ( and as i wrote I dont know if my new one is good).

Now I hope to learn how to test it.

One contributor writes :::
The voltage specs are 0.980v - 1.030v. If your MAF reads above this, it is bad. Occasionally, the MAF volts will be in specs, but the part-load specs will be out of range (meaning that the MAF should flow apporx. 20kghr at part-load, but it registers a higher flow rating), this gives the code P0175 Self adaptations at part load factor. Enrichment at permissible limit.

How on earth do I read the Voltage on a MAF ?

thanks again.

w163ml · #6 12-20-2006, 04:52 PM

Quote:

Originally Posted by sdanville

thank you for the link

How on earth do I read the Voltage on a MAF ?

thanks again.

Don't know, but the following TSB provided by Wolfgang may help:

http://www.alldata.com/tsb/Mercedes-Benz/1059030000000_1065510000000_T-07-07-35/index.html

sdanville · #7 12-20-2006, 05:47 PM

this may be something...
I have to study it more.
it appears it is testing the connection that goes to the sensor vs.
the sensor itself as the ignition key must be on.
2007 update, it was easier to order another brand new one.

Should be here Monday. I will report if that is the Cure.