Hello everyone, I have been away for a while and moved to Charlotte, NC. My car has been running good (with normal maintenance and replacements) until recently. My check engine light came on yesterday so I got my homemade scanner tool out and got the following codes:
Pin 3 - code 19: Fuel Injectors open/short circuit or self adaption in engine control module (N3/4) at limit;
Pin 3 - code 22: Camshaft position sensor signal defective;
Pin 8 - code 20: self adaption at idle speed or upper/lower partial load at rich or lean limit;

I was able to clear pin 8, code 20, but not pin 3 codes. The check engine light went off but later came back on.

I am not sure if all the codes are for the same problem?

A little history about my car - 205k miles, 4 years ago the wire harness was replaced (purchased from a long time member of this forum), the throttle body was replaced, the OVP, oxygen sensors, spark plugs, fan clutch. A couple months ago the water pump and fan bearing/housing were replaced. A week ago I sprayed some engine cleaner and water around the power steering pump in order to clear the NC safety inspection. The car currently runs good/smooth acceleration starts without hesitation.

Any help is much appreciated, Thank you.

Not sure that you have correct info posted . . .

In the 2nd entry, you incorrectly wrote "camshaft" instead of "crankshaft"!

Pin 8 is the HFM Module. The "self-adaptation" error only shows in the "diag module" and "fuel module". It can be cleared but only for a short time. I'd bet that the CE light coming on will show the DTC#19 code error.

The DTC#19 error is a PITA and if it's real (check ALL vacuum lines for a leak including the rubber nipples), then info here details the problem for the "V8" engines. Sorry, don't have an eprom for your engine but the problem is the same.

__________________
Regards . . . . JimF
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'94 S500 Cpe

Visit my Mercedes Web Page

Thank you for your reply, but another member recommended I check for vacuum leaks and fuel pressure, which is what I will attempt to do today.

Do you know if the crank position sensor error will stop once the S/A error is fixed?

See my post in #2 above . . .

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

I replaced the air-filter and cleaned the MAF with the recommended CC cleaner. I checked for vacuum leaks, but do not know how or where to check so I only looked at tubing I could see without removing any parts or covers. I looked at the fuel pressure regulator - took the vacuum hose off and noticed the smell of gas in the tube, but was not able to blow air into the valve.

I found the following in the service CD (Copyright Daimler AG 11/4/08), "Note regarding mixture preparation self-adaptation: ....Should malfunctions occur in the form of:
-Intake air leaks.
-Injector wear or carbon build-up.
-Engine wear.
-Contact resistance in MAF sensor.
-Defective diaphragm pressure regulator.
-Defective purge control valve."

Do I need to check every vacuum hose for a leak or are there specific "intake air" connections I need to focus on?

ji_mbenz, the line from the fuel pressure regulator (fpr) to the valve cover is a vent line. If the fpr diaphragm ruptures the vent line directs gas into the valve cover to prevent it from leaking onto the hot engine and potentially starting an under-hood fire.

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Fred Hoelzle

The tube connecting to the fuel pressure regulator diaphragm nipple is a vacuum tube.

After I cleaned the MAF and installed a new air filter, I then cleared the codes; except for the DM (pin 3) code 19 - it would not erase, but the CEL went off and has been off for the past 10 trips. The motor runs good, the same as before this happened.

The only vacuum related issues in the past involved the trans upshift delay so I had that vac line plugged.

Tha'ts interesting . . . since if it's a "real" DTC#19, the CE light should come on?? So maybe, it WAS a vacuum leak/MAF/FPR . . . and you fixed it??

That doesn't act like any #19 code that I've seen. . . but there's always a 1st time for everything!

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page