I read somewhere that this may need just a cleaning rather than replacing
when they generate an error code. I removed the sensor from the housing to
take a look at it and it looked clean. The piece that is actually protruding
inside the housing looks like a printed circuit board, I'm not even sure how
you would clean this. Any advice anyone, is it possible to clean it or
should I replace it? The best price I could find on the web for a
replacement is $307, is this about the norm?
CRC makes an MAF cleaner. It is $6 a can at Pep Boys. For some people the
effect lasts. For others it only helps for a day or maybe a week (my case).
The key is to get a spray that does not leave any residue. Some people use
brake cleaner or electrical contact cleaner but I would spend a couple of
bucks more to get the dedicated stuff.
You might want to check GermanStar.net in CO. They sell the insert piece
only (which you now know how to pull out) for some Mercedes at reasonable
prices. For a C Class, it is only $129 plus $10 shipping. I called and
asked them about it and they said it is a genuine Bosch part that is the
right one for the car. You don't get the plastic surround tube but you know
how to swap out with your old one, so just clean up the old tube and save
I just ordered one from German Star for $99 plus shipping. The guy was very
up front about the sensor which isn't a Bosch part saying that one in ten
are dead on delivery, but it has a twelve month warranty so you can return
it for a replacement. Also, once installed if they work they generally last
as long as the OEM part.
I need to replace the oxygen sensor before the cat as well, it looks like
you have to jack the car up to get at this, is this correct or I'm I looking
in the wrong place?
You are definitely looking the right place. Sensor is located between
exhaust manifold and catalysator. It has one electrical wire on it and
there is nothing else like this there.
Is this I6 or V6 engine? V6 has 2 Oxygen sensors (one at each side of
the engine) but I suppose I6 has only one.
That is very interesting. Maybe it is a Pierberg. When I called last week,
I specifically asked the guy if it was a Bosch or something like a Pierberg.
He assured me it was a Bosch OEM. This was for a C Class though and $129
instead of $99. Maybe that is the difference. Makes you wonder though...
I received a PO170 code on my '97 E320. Started and ran perfectly
otherwise. Prior to the code display I had checked, but not replaced,
the paper air filter element. Some dust must have been deposited onto
Paid dealer $70 for a diagnosis and estimate only. Diagnosis was MAS,
estimate about $460. Car's mileage about 37K - 38K.
So with nothing to lose I removed the MAS and then the sensor from the
stovepipe housing. Then I used a (smoker's) pipe cleaner to very very
carefully brush the wire(s) clean. I didn't see any dirt or dust on the
pipe cleaner so the MAS must have been pretty clean!
That was about two years ago so my careful cleaning must have worked and
it saved considerable $$ vs. the dealer's $460 estimate.
During the investigation I noticed that the MAS for my '97 E320 has an
"early" and "late" version - your car may be similar. The "early"
version can be disassembled, I'm not so sure about the "late" version.
My 96 E320 MAS can be dismantled too, however it isn't a wire element, it
looks more like a small printed circuit board.
I managed to get a non-oem replacement for $99, this is just the sensor NOT
the complete housing. The connector for my MAS is a round twist on style
rather than a standard push in connector.
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