Bought my C55 a few months ago. Absolutely love it. Soon afterwards, I did the secondary cat delete, resinator delete and muffler delete. Car has run perfectly since the mods. This past weekend, I did an oil change. Took the engine cover off to check the air filter (stock), re-installed cover, finished oil change. Approximately 30 miles later, car started to surge at low RPM and stalled a couple of times and check engine light came on. Stopped by Autozone-had it scanned, got code P0101 which indicated MAF sensor problem. Today, I got some CRC MAF cleaner, cleaned MAF, disconnected battery for a few minutes. Started engine CEL light was gone. Later, restarted engine and light re-appeared. Drove the car and it ran fine-no surging, no stalling but light still on.
Sounds more like a vacuum leak to me. I would inspect all your vacuum lines to ensure one isn't cracked or disconnected. A few weeks ago a vacuum hose on the rear of my engine by the supercharger managed to completely disconnect itself. Think the pending code I pulled was P0105. Was running very rough, and nearly stalling out. Once picking up speed, and RPM everything seemed fine. Never got a CEL just that pending code.
Originally Posted by http://www.obd-codes.com/p0101
* Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
* When the engine
is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
* Any loss of vacuum to the MAP sensor can cause this DTC to set.
I don't know if the oil is a problem, but you will probably just end up needing a MAF did you have it re-scanned? I will attach the approved oils that MB recommends here. You should probably stick to this list.
I agree that there's probably some sort of air leak. Recheck to make sure the airbox is fully pushed onto the MAF. That's the only sort of air connection that I could see as compromised, as there's not really any other hose that would be involved in pulling the airbox off.
Originally Posted by superstar
I do not think cleaning the MAF would solve the problem. As far as I know, if the MAF starts to fail, then you must change it with a new one. This is a very common problem with Mercedes modern cars.
While I agree that the MAF itself is probably not the culprit in this case, cleaning a MAF can help in certain instances. The usual problem is an over-oiled K&N air filter, which then deposits the oil onto the MAF elements, allowing dirt and grime to accumulate on the elements, causing false readings.
Today I removed the engine cover, made sure I had a good tight seal on the throttle body. Disconnected the battery again-same thing happened, started the car, no check engine light. Test drove it and the check engine light came back on. The car runs fine except at very low RPMs just after taking off from a stop and it has a small hesitation (surge). When you come to an abrupt stop, it also surges...almost dies. Tuesday, I sprayed CRC MAF sensor cleaner in the throttle body and let it sit long enough to evaporate. I did not remove the throttle body because I wasn't sure how to do it.
Yes, I removed both bolts from the oil pan and when i drained the oil.
Does anyone think that 5W30 oil is an issue? is it just a coincidence that this all happened after the oil change?
I don't think it's related to your oil change. However, why in the world are you using "Penzoil" on your expensive Mercedes-benz? Stick with the good brands. Mercedes only uses Mobil-1 for their oil, but others are approved such as Castrol. Just did an oil change with Castrol Syntec 5w-40. Not sure if that Penzoil is approved, but even then the viscosity is too low. Recommend staying 0-5W40...
This might sound like a stretch, but check to see if you have knocked the red oil dipstick tube plug out when you removed the air box, it's pretty easy to do and I have seen German engines that need to be "sealed" to run right. Knocking the plug out is very easy to do and sometimes not noticed.
It won't matter in the least if the air filter housing is on, on right, or missing............as far as the engine and MAF are concerned. It does matter as far as keeping dirt out of the motor and is important to have it installed correctly for that reason, but not as far as running is concerned. If the MAF is off or not sealed on the intake side you would have an issue, but not on the air box side. Nope, I'm still betting the dipstick tube plug is missing and got knocked out when the airbox was lifted.
91% isopropyl alcohol & q-tip is much more effective way of cleaning it (gently of course). The CRC mass air sensor cleaner is NOT residue free like it claims, in fact it leaves alot of residue to be honest. I have a suspicion its just their normal electronic parts cleaner re-branded as an MAS cleaner for marketing purposes.
Check your MAF seal that is on the air bex, I have seen quite a few get torn, or pinched if not put on right. Also make sure you didn't break the lower clip on the MAF elbow, or the vacuum line to the booster.
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