I am new to this site. Your hel or advise will be appriciated. I have a 1996 S500 coupe with 92,000 mi. Several months ago the Engine light came on and it read the P0410. The injection pump, valves openning and closing were checked by MB mech. the lines were replaced. the fuses are fine as well. I cleared the code and the engine light and the same code comes back. have been chasing this problem for months now. I need to get the inspection done but with this situation it fails. please advise. thanks in advance.

When the airpump kicks in ( on start-up ) the oxygen sensor has to show a lean condition.
If the sensor is suspect, you may want to have it looked at.

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2007 C 230 Sport.

How can the 02 sensor show anything until it is in closed loop and hot????

The ECU does an AIR system self test AFTER closed loop condition has been attained....NOT at start-up..

..but the rest of the info is correct.

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A Dalton

The common issue on 119 engine secondary air codes is plugged passages in the cylinder heads. Not a nice situation.

Pretty easy to test for though. Run the second air test with SDS with engine warm and in closed loop. Pump runs and O2 sensor voltage must drop below 40 or 80mv (later cars go 40 early 80, this one probably 80). If it won't go 80 then one opens the vacuum line to the brake booster. If a sudden gulp of air there drives the O2 voltage below 80mv where the pump wouldn't then the airflow from the sustem is low. Verify check valve openning and cry.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

It seems like pluged passage. does the engine have the right and left passage lines? If it does, how do I know which one to go after? And the most important how big of a job is it (hourly)for getting it done by a shop. Thanks.
meran

Oh Arthur,
If it wasn't for a kick in the ass from you once in a while, I'd feel neglected.

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2007 C 230 Sport.

Yeah, ..and I know how much you like it....

Actually, you were pretty close on that one.


Hold on . Hold on... " Judges, Judges ..what say You ?????? "

DIng-Ding -Ding ..

" Judges say OK - Close Enough !!! "

Alright Alex, .... uuuum.. Let's try " OBD2 CODES" for $600.....

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A Dalton

After replacing a few lines and valves the check engine light continued glowing. I decided to get the car to the dealership for a good inspection and advise. The report came out to be blocked ports. the solution is to take the engine apart, send it to a machine shop to clean the carbon from the ports and put everthing back. The cost of about $3500. I have had MBZ before and never a problem with clogged ports at 94000 mi. But I guess it happens. Please offer any idea you may have in cleaning ports. Thanks in advance.
Meran

I know it's not a M119, but I've been under the understanding that they designed both engines similarly.

My M117 has the aux air runners cast into the intake side of the heads, with a passage joining them through the intake manifold. When they get fouled with carbon from the exhaust flowing back up into them, you end up having to tear the intake off, at minimum, to get to them and clean out the accumulated carbon deposits blocking the ports and channels that the aux air is routed through.

Again, it's not a M117, but I cleaned mine out while I had the intake off, just to be on the safe side (even though I don't have aux air connected currently on this car). On this engine, it's not an impossible task, but you should definitely know which end of the wrench to hold before diving in in your own garage. Not being my daily driver, this is a "just for fun and learning" engine rebuild, and it's involving lots of learning!

Best of luck with it, and sorry to hear you're having trouble.

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...

How many miles did yours have? I am hearing it is very unlikely for a benz under 100,000 to have a problem like that. Dealership did not explain to me how they arrived at that decision? What else could give them such reading as the ports are not operating right. any ideas?
Meran