Seems like these codes comes up often for this model. I ended up replacing the engine control module, the last step, after various other checks.

Pin 8 code will come back long before the check engine light illuminates. You can reset the adaptation by clearing pin 8 again after you have cleared all the codes and get 1 led flash.

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Zafar
94 E320 58000 Miles

Thanks, Kestas.

Exactly.

Clearing codes and resetting memory mean with the code retrieve tool are two completely different procedures . I did not want to get back into this thread when it got hi-jacked , but , as Z states .. get the ECU back to Mean and then go back to pin 8 [ and 14 , as as CTP sw can be faulty]for code fault storage . The CE is simply getting the end accumulation of faults detected by the HFM/SFI and AE/CC modules because they have finally reached the point of affecting Emmisions Mandated Faults [ That is what the N/59 module does and that is why I had you go to pin 8 to see which engine management faults were finally causing the Emmissions Module [N59] to activate CE lamp. As you can see , the problem you have is directly picked up at pin 8 module and is a A/F mix that is out of ECU lambda limitations to correct.
Cutting and Pasting code charts to remedy your problem do nothing to help rectify or interpret your a/f problem. And simply clearing a CE lamp does Absolutely nothing to address the problem, except turn off a light..
There are several simple checks to be made from that modules info , which
are from a bad fuel pressure regulator and vac leak , all the way through the system to the the ECU [ as in Zaf's case .. I remember that one]
Get the memory reset on 8/14 and then check for vac leaks and fuel pressure diaphragm leak at intake line/fuel rail. Look for any eveidence of raw gas at the vac line port of regulator, as this is a common fault, as is the white plastic vac. line crossing the front of the engine going to the Switch-over-valves . They break from heat fatigue and crack on all 104s. The recommendation here is to eliminate the plastic and go with full length rubber hose to SOVs..
There are other simple checks , but these would be first possibilities on my list due to high frequency fail rates and checking simplicity..

Sorry, I didn't mean to sound so mean or concieted in my post. I didn't know if Ketas had checked that link. Obviously you know more about the cause of the codes than I do. I know that we all appreciate your help around here Arthur.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

The check engine light came back on this past weekend.

Built-in reader:

Code 4: Air injection system faulty hot film mass air flow sensor with hot wire.

Code 19: Injectors circuit open or circuit short emission control module adaptation in engine control module at limit.


Pin 8:

Code 13: Idle speed control (ISC) system at upper or lower control stop or CC or EA indicates "limp home" mode.

Code 20: Self-adaptation at idle speed or upper/lower partial load at rich or lean limit.

Pin 14:

Code 2: EA/CC/ISC control module (N4/1) or Safety contact switch (M16/1s1) or Stop lamp switch or Cruise control switch or Actual value potentiometer or Starter lock-out/back-up lamp switch or engine speed signal or vehicle speed signal or closed throttle position switch or safety relay in EA/CC/ISC control module.

Code 5: Stop lamp switch (S9/1).

Code 11: Closed throttle recognition signal to engine control module (HFM-SFI or Left LH-SFI) Fuel safety shut-off to engine control module (HFM-SFI or left or right LH-SFI).


The car runs fine and the codes are now cleared. Both times the check engine light came on was during startup and stayed on through several start cycles until I cleared the codes.

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95 E320 Cabriolet, 159K

Were you able to fix the problem?

I had codes 3,4,19

Pin 8 13, 20

and a few for Pin 14

Very similar to what you have. Again, replacing the ECM fixed all the codes for me.

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Zafar
94 E320 58000 Miles

Not yet. The car is in storage until springtime.

Before storage I replaced the O2 sensor and still had problems. Since then I started another thread, which I believe is related to this problem:

AIr Pump Won't Shut Off

This problem presented itself about the same time I was having O2 sensor problems. I think the problem is that I spliced an O2 sensor that works in olders models but is not appropriate for my vehicle. I've been researching the sensor part numbers and I find that the universal sensor for each application is different. My next step will be to buy the proper O2 sensor. Hopefully all problems will then go away.

I'd hate to think that I need a new ECM. How much did it cost you? How can it be best diagnosed?... dealer?... indy? It would sure be nice if I could swap it out for just a day for diagnostics.

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95 E320 Cabriolet, 159K

Dealer wanter $1800 but I got one from the "recycle yard" for $150. Took me about 10 min to install. No recoding required for me atleast. My car is California emissions with ASR.

Before the Swap, car drove fine, except for the check engine light, that would illumintate a few days after resetting adaptation.

Dealer can easily swap it out for you for testing.

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Zafar
94 E320 58000 Miles

This may make sense because the relay for the air pump is integral with the ECM. Anyhow, thanks for this info. Hopefully it leads to a solution to my problem.

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95 E320 Cabriolet, 159K