newton22

Yes, I did search the board and came up with many answers. The probable causes I have decided are:

-MAF sensor
-O2 sensor
-Dirty injectors
-Damaged tank cap seal

However, I just want to see if any w220 owners have had the light and these codes thrown before. All the threads I found on the subject were under the E, CLK and SLK forums.

I think I will start by cleaning my air filters (or replacing) and then cleaning the MAF.

mbtech360

Check for small vacuum leaks, rotted hoses ect... will cause a adaptation code.

Jayhawk

http://www.obdii.com/codes.html

newton22

Yeah, I know what the codes mean, but they usually don't tell you too much.

Jayhawk

My CEL has come on many times, but I have never actually seen a code #. The only thing I've had to change is the MAF sensor and I believe the catalytic converter was involved once.

lionj

Mine just came on too. Was wondering the same thing Newton22, I will monitor and check air filters and gas cap before moving to MAF sensor, let me know what you do.

Jayhawk

It may just be superstitious, but my CEL seemed to come on more often when I filled-up w/ the engine running than when I shut it off to refill the gas tank.

newton22

Scan it first. I scanned right away after the light came on and it threw two codes.

newton22

I sprayed my MAF and the light went off for two days and today, it came back on.

ugh.

Jayhawk

You are probably going to have to replace it. See you dealer!

newton22

Eff that, ebay for me.

Jayhawk

Good luck!

fusion2007

haha thats the way to do it... it should be no problem for you. if u can take your engine apart like you did for your thanksgiving tune up watever... then this should be pretty easy

lionj

Hey Newton22,

What did you spray your MAF sensor with?

newton22

http://www.amazon.com/CRC-Mass-Flow-.../dp/B000EGH57G

lionj

Thanx, Newton22

S500Sport

The check engine sign popped up on my ride too.

TJC

Re: P0170 / P0173 codes. I just solved the problem a few weeks ago on my ’01 E320 – the control systems are similar enough that it should apply to your situation. The dealer misdiagnosed the cause as a failure of the two rear O2 sensors. Both failing at the same time seemed unlikely and I bought a cheap Actron code reader (#CP9175, ~$120 on Amazon.com). When I looked at the freeze data, some of the fuel trim (long and short) numbers were out of range. The trouble events were at idle. As there were results in the fuel range registers, I assumed there was some data from the O2 sensor. A little reading on the net confirmed my gut reaction: there are specific codes for O2 failures and I did not have those. Fuel trim results are ratios, and rather than suspecting both devices on one side of the fractions, I looked at the common device on the other – the MAF. I also suspected a possible vacuum leak as the events were at idle, but the test for that was negative. My problem was a dirty MAF.

To clean it correctly requires a torx anti tamper driver (I think it is #20, but might be #25). There is a little button in the middle of the “star” that makes a standard torx driver useless. I bought a set of hex drive torx bits at Kragen for about $11.00. Remove the MAF tube housing from the intake, remove the MAF sensor from the tube housing with the torx driver. There are two measuring points in the MAF that need cleaning: a plate inside a venturi, and two wires in an enclosure at the bottom of the sensor. The plate is some non-corroding metal and measures air density by the cooling effect of the air flowing through the venturi across the plate. That plate will eventually get dirty and must be cleaned (my car had about 65,000 miles when the CEL came on). I cleaned the plate with CRC MAF cleaner and a q-tip and sprayed the lower enclosure with the wires too. Don’t touch the wires, as the unit will be ruined if they are damaged. Only use MAF cleaner or electrical tuner/contact cleaner like the stuff from Radio Shack. Carb/choke and brake cleaners will leave a residue that will make the problem continue. Let the sensor dry, and reassemble.

The whole operation took less than an hour. I erased the codes and the CEL went out. I have not had any problems since – 16 engine warm up cycles. I tried to figure out what the cause of the problem was, as the sensor seems to be OK now, and had functioned fine for over six years. My only guess is I put a K & N filter in about 18 months ago. It might be the oil from that filter building up on the sensor plate and fouling it.

Try this before you waste money on the new parts. The dealer wanted to put in two O2 sensors at about $600. They would have hit me for another $500 for the MAF when that attempted fix failed. My code reader has already paid for itself many times over. It will get more work in the future as I have lost faith in the dealer’s ability to accurately diagnose problems. If the orange light of irritation comes on again, I will no longer be at their mercy.

f2daizm

one ? where is the maf located................any pictures?

TJC

The MAF is between the air cleaner housing and throttle body (usually mounted on the intake plenum). It is a round, black tube about 3.5-4" diameter, with a multilead plug on the side. No photos, but here is a link to Autohaus AZ's page for the MAF for the S430: http://www.autohausaz.com/search/pro...0Mass%20Sensor

S500Sport

Please write more about this topic, the CEL still comes on I think its the MAF too.

ohlord

read your codes?
You need to rule out other possible issues,not guess at a Mass air sensor.
If you have an autozone near you they will rent you the obd2 scanner for free
or you can get your own hand held scanner at harbor freight tools near your or online Item #94169 for $39 -$59 on sale store will meet internet price if you take copy of ad.
Read the codes.P0170 and p0173 often can be solved by cleaning with crc brand maf cleaner and diy on benzworld,org w210 diy section
P0100 maf code circuit is dead you need a new maf.If cleaning does not work and clear codes you need a new one. $200 at www.autohausaz.com free shipping and about 15 minutes of your time to install.
If it is the fuel trim codes don't ignore them to long,it will eat your cats alive and then your cost to repair will go way up.

when you have the codes post them.
Also never touch any part of a maf with a q-tip.use only the spray crc brand maf clearer.

my06clk

Do you guys know this thread is over 2.5 years old?

my06clk

Do you guys know this thread is over 2 years old?

newton22

Yes, it's 2 year old thread. I have long fixed the issue. A new MAF fixed it.