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Registered 2003 SLK230K
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Discussion Starter · #1 ·
May 2015, finally found the root cause for my persistent P0410 "secondary air injection system" code. Purchased the car in July last year, took 10 months mainly to search and buid up the courage to take stuff apart.
I first replace the "shut off valve" 002-140-55-60, (red arrow foreground) no results. At the same time purchased the "check valve" 002-140-68-60 (red arrow back ground), this one sits on top of a pipe and access is very limited, was not able to remove old one.
When I finally found the courage to remove the air intake system and the compressor did I have the access required to unbolt the where it attaches to the block, on the RH side below the exhaust manifold.
Once the check valve replaced P0410 persisted.
I then figured how this actually works, compressed air was coming out of the big hose going to the shut off valve, but not coming out the other side.
I then sucked on the vacuum line (blue arrow) and air come out the other side of the shut off valve. Found no vacuum coming from the hose going below connecting to the intake manifold. Removed the hose from the intake manifold an noticed a thingy on top of it (orange arrow). This thingy is another check valve 002-140-84-60. I sucked on both sides and it works as it should, remembered how it came off and concluded it was upside down, installed it correct and the air now came out of the shot off valve as supposed.
I can't believe the PO (a self professed shade tree mechanic) did not notice this (he replaced the change over valve (purple arrow), sender unit (green arrow) and MAF, I have those parts). He also said Carlton Mercedes in Greenville SC checked it out and couldn't fix problem.
I re-connected the shut off valve to the check valve, secured everything and started the car, shut down immediately, twice. I then stepped on gas a little when starting, ran but rough. Drove around the block, ran ok after warm up. Did this several times. Cold start and drive around block to warm up. Every time it ran rough when cold, but a little less so every time. Keeps throwing P0106 now (manifold absolute pressure/barometric pressure circuit range/performance problem) Guess I'm off chasing that one.

Any suggestions?
Thanks, Ad
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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5,624 Posts
I'm not sure about your engine but the 272 has both a MAF and MAP sensor, with the latter only used during starting.

Any chance you knocked yours loose when you were in there?

Good find on the backwards valve!
 

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I find it difficult to follow what you did. Since, I think, the problem isn't solved, are you sure the valve was backwards?

A simple fix for the secondary air pump system is to disable it. The car will run fine without it. Notice the car has both a MAF and an MAP. Either one could be designed to do the job.

Mercedes in its infinite wisdom want everything to be perfect, so they come up with these Rube Goldberg systems which have a habit of failing.
 

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Registered 2003 SLK230K
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44 Posts
Discussion Starter · #4 ·
Maybe I'm a bit confusing.
My problem was P0410 code, secondary air injection system, and yes the car does run fine like that, but the annoying MIL stays on. Then you don't know what else pops up.

I did fix the secondary air injection system, done.

Immediately after have P0106 popping up, I'm looking still to get that fixed.
I did have P0106 once last year, but I was focused on P0410.
Now after the secondary air injection fix the motor stalled twice immediately after start. Then I started and pushed on the accelerator a bit, motor continued to run but rough. every time P0106 message came up.
After several starts and warm ups over a couple of days the car is idling and running a little better each time. Still the RPM jumps up a few times when idling, and still cold.

I'm wondering if the ECU had learned to deal with the secondary air injection malfunction that it now must re-learn how to work properly? Could this settle in over some time?
Should I disconnect the battery to reset ECU?

Online one OBD website said to check voltage on MAP, should be 4.5 motor off, and about 0.5 when idling. I think I saw the sensor, as you said the MAF may have the same function as well.

I use OBD fusion app to read OBD info, I did not see a readout for MAP, do you know if it has that? I'm struggling to understand all the values I can read from the car, they are only good if you know what the correct value is, under given condition.

This should be enough before it gets confusing again.

Thanks, Ad
 

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Registered 2003 SLK230K
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44 Posts
Discussion Starter · #5 ·
Was not correct on voltage, the ODB-codes.com website shows the below explanation:

The PCM supplies a 5 Volt reference signal to the MAP sensor. Usually the PCM also supplies a ground circuit to the MAP sensor as well. As the manifold pressure changes with load, the MAP sensor input informs the PCM. At idle the voltage should be 1 to 1.5 Volts and approximately 4.5 Volts at Wide Open Throttle (WOT). The PCM looks for any change in manifold pressure to be preceded by a change in engine load in the form of changes in throttle angle, engine speed, or Exhaust Gas Recirculation (EGR) flow. If the PCM doesn't see any of these factors change while detecting a rapid change in MAP value, it will set a P0106.

Read more at: P0106 DTC Code - Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem
Copyright © OBD-Codes.com
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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Ad,
What values are you seeing on your MAP? Are they close to the documented value?
 

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Registered 2003 SLK230K
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44 Posts
Discussion Starter · #7 ·
i wasn't able to find the readout for it in the OBD fusion app. Just looked again and it seems to be under SAE PIDS.
I'm traveling this week so can't get to it until this weekend.
I'll keep you informed.
Thanks for helping me with this I really appreciate it.

Ad
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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5,624 Posts
Given the nature of the code, you probably will have to use a multi-meter to learn the analog values.
 

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Hi concerning your problem I can give you some tips to isolate your problem (those worked for me)

The valve with pipe operates only in the first start of a cold engine ..and then after ex:5 or 10 min for a few seconds just to verify that the valve is operating .
To check the operation of the valve you have to disconnect the black pipe after the valve and put your hand to see if air is coming out , if air is coming out then it is ok.
If no air is coming out then you have to focus on your purple arrow and the small pipes .
As for the map sensor there are 2 of them ,one is your green arrow for measuring the barometric pressure of the atmosphere and an other one on the intake manifold to measure the pressure of the intake.
Those 2 looks exactly the same and they have the same part number so you can exchange them , you are going to have the same error but the engine will start normally.
 

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Registered 2003 SLK230K
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Discussion Starter · #10 ·
Thanks Efair,
I tried the volt meter way, don't have access to the conductors, all water proofed.
I will start a new thread for P0106 as this one seems to get too mixed up and confusing.

Really appreciate your help.
 
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