animelchild9

Hi all,

I gotta say i love this site, but this is my first post since I have exhausted all options... My benz has a c/e light on, and the stealership said it was from front o2 sensors, or a bad cat, or clogged headers... prices are $1k, 2k, and 4k...

My problem: the C/e light is on, when in park or drive and idling, the rpm constantly drops almost as if it wants to cutoff (but never does).

Things I have checked/replaced: I had drivers side cat replaced 2 years ago, passenger side last week, both front o2 sensors, all the PCV sensors under the hood, all of the PCV lines and rubber booties, the rubber hose going from top left of engine to location of MAF.

I have also cleaned the temp and MAF sensors. But it still happens!!!

My uncle asked me if i thought it could be clogged or faulty injector? do i have to take it apart and clean the headers (and if so is it easy/practical?) The only error code is the "secondary air pump failure" code from autozone (quite generic unfortunatly)

I pray to the mighty gods of MB world anyone have a clue?

Plutoe

Change out the secondary air pump!!!However if it were me I would first test with my DAS Xentry.

siopaolover

I'm having the same problem! Cleaning the MAF sensor helped for a little while, but now it just does it again

Plutoe

That's because the MAF aint the problem-----keep spraying and you will need a new MAF.Then you will be whining about the cost of that!! Locate and understand the problem before you start to putz ariound!!

Is your CEL on!!If so read the fault or faults!!

animelchild9

I did have the codes pulled, both at the dealer and AAA, they both came back with the p0410 or w/e (secondary air pump)

If its the air pump, why did the stealership say the o2 and cat's... "its not the air pump" they said. were they just trying to stealership me out of 2k? ***arrg hulk smash***

I am thinking eventually it be necessary to buy a code scanner of my own, since i do my own work after many many lies. Is the DAS xentry good? I'd like to get something under $200 that reads everything but would alst me for a few more cars...

Plutoe

My response is based on what you have said, I have no FI what the dealer said, all I can tell you is that if they used their diagnostic tool(DAS) to read the fault you should have asked for a copy of the quick test that they would produce to understand what is causing the fault---then there would be no BS as to who said what or did not say what----you would have a copy of the test.

Another point----has anyone cleared the fault, if that is the case did P0410 return??

DAS will cost about 5-600 bucks and then four months to learn the system

illest

do a search on this forum and the other forum and you will find several posts with information on how to fix the issue. Get a cheap code reader from HF so you can read the codes yourself.

animelchild9

I had done forum searches before which is why I had done the PCV system, all hoses, all sensors. Maybe im just not doing the right search term "e420 idle issue" So i dug through my papers, it looks like they put it in my glove box with my other receipts

"secondary air injection fault code found, tested pump specs and pump works properly. checked vacuum line and vacuum is fine. live codes read Oxygen sensors do not drop to 40mv. suggested causes: faulty o2 sensors pre cat, clogged exhaust or clogged cylinder heads, no outstanding recalls on vehicle parts, will do courtesy car wash"

according to what they checked, the heads are the culprit, i have never heard of such a thing that they get this bad to cause issues. I didnt install the o2 sensors as the place i took my car to get inspected said they would do it for free, they were direct bosch replacements, ill try to check their work (i wish you could trust places )