320 is running great, but I am getting a CE light about every two weeks or so. Code 4 on the DM, and code 11 on pin 14 . I see what the codes translate to but don't have a clue about what to do next. Do I take it to my tech ?

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

Here's the DTCs:

4 - Air injection system faulty hot film mass air flow sensor with hot wire

EA w/ ASR
11 - Closed throttle recognition signal to engine control module (HFM-SFI or Left LH-SFI)

Check out MENU#4a and use some MAF cleaner; works nicely on 'hot-wire' MAFs as it worked great on mine!
Also a cracked vacuum line will give #4 code.

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Regards . . . . JimF
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'94 S500 Cpe

Visit my Mercedes Web Page

Check AIR pump to see that it comes ON when cold. The same 12v. signal for pump also feeds the AIR SOV. If No sig, check fuse.
If yes , then a common fault on that chassis is a broken vac line under the engine front cover. White, plastic line going to the AIR SOV under the cover [ cover just snaps up/off.]
If All looks well , then you want to check the 02 sensor. Air system uses the 02 to monitor if the AIR system is working by doing a self test and looking for an extra lean reading at 02..if sensor has lost the ability to read that low/lean, it will trigger AIR system as faulty even though it is not.
Problem is weak sensor in that case.
Common CTP code is there is not enough slack in the cable [ 1/4" ] at idle
or sticking cable..also check that you don't a a rug/mat bunched up at accelerator...
Cable is adjustable with turn wheel and lube it ...

Thank you guys,,, you are always around when I need help. In my last foray, I was having a vaccum leak and it turned out to be the crank vent tubes. In my pursuit of that issue I replaced the O2 sensor,,, all the vaccum lines on the front of the engine, cleaned the MAF, and every other issue that was related to a surging idle. The AIR pump seems to be working as I can always hear it when the engine is cold. Will check that cable slack though, but the dang thing is really running great. Thanks again.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

Ok..
If the 02 is new and the pump is coming on with ECU demand, then the problem is that the air valve between the pump and the head exhaust ports is not opening. That is what he SOV does , it allows engine vac to pass on to the AIR valve when the pump comes on.. and that air valve allows the air from the pump to go into the exhaust ports of the head and cause a lean condition at 02 , verifying system OK....so you want to look at that valve, the vac line going from the SOV to it, and also check that the SOV does open when 12v is applied. The SOV is mounted in tandem with th EGR SOV.

I have also seen situation where guys have mistakenly switched the wires on the EGR/AIR SOV connectors b/cx they are right next to one another and that will give you the same fault. [ although usually also with a code 5/egr]
Those would be my next diagnostic steps..............

If you have the CD , go top Emmissions and look at vac schematic and you will see the entire AIR/SOV/Vale/ and check valve routing layout.