w124 280e M104 error code 23

xitrum_dalat

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HI every body. I'M NEWBIE HERE,HAVE SOME QUESTIONS .

AFTER CHECK ERROR CODE BY HOME MADE CODE READER,
I FOUND CODE 23 IGNITION OUTPUT STAGE 2 OR COIL(3-4)

AT FIRST I THOUGHT THAT IT'S IN MEMORY ERROR B CAUSE
I'VE CHANGED ALL NEW 3 COILS.( the coil for 3-4 is broken)

SO I ERASED THAT CODE. AFTER 1 DAY ........ RECHECK

IT APPEARS AGAIN !......

THE SITUATION IS

THE ENGINE IS RUN PROPERLY, EASY TO START
RPM WHEN HOT IS 850 RPM .... NO SWING
RUNNING SMOOTH

BUT THAT CODE 23 ANNOY ME VERY MUCH

IT INDICATED THAT MY ENGINE HAS PROBLEM.




WHAT I'VE DONE IS AS FOLLOWS

CHANGE 6 SPARK PLUGS
CHANGE NEW SPARK WIRES
CHANGE 3 PLUGS UNDER COILS
CHANGE O2 SENSOR ( B cause it short circuit in heater)
CLEAN ALL PLUG RELATED TO COIL AND IGNITION BY DEGREASE
CONTACT CLEANER

OPEN THE ECU THE CIRCUIT LOOK GOOD THE 2 BIG CAPACITORS
ALSO LOOK GOOD GOOD SHAPE AND NO LIQUID LEAK.

SO I CLEAN THE PLUG TO ECU BY CONTACT CLEANER TOO.

MY ENGINE WIRE HARNESS HAS BEEN CHANGE 5 YRS AGO



BUT THE ERROR CODE 23 STILL THERE !

PLEASE GIVE ME SOME ADVICE.

THANKS
 

television

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2002 SL500, 216 CL500, all fully loaded
Hello and welcome,what I would do is to leave it, the code is only an indication in the electrics. As the car is running correctly wait and see
 
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xitrum_dalat

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thanks Malcolm,that's
What i'm doing.
Any further advice pls.
 

124coupe

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Swap over two of the coils and see if the fault moves - that will tell you if it is the coil. If it stays the same, then its ECU output stage or wiring to the coil from the ECU.

Are you sure the harness was changed and not just "repaired"?
 
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xitrum_dalat

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swap over two of the coils and see if the fault moves - that will tell you if it is the coil. If it stays the same, then its ecu output stage or wiring to the coil from the ecu.

Are you sure the harness was changed and not just "repaired"?

i've test by swap coils , result the same code 23


for changed wires harness , for sure it 's done.

Changed new one.
 

124coupe

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OK, sounds like the original broken coil for 3-4 has damaged the output stage (2) in the ECU? Refurb is not expensive but its inconvenient!!

I would still check the wiring from ECU to coil and check the resistance beween the two wires while waggling the harness.

Otherwise learn to ignore the code if the car still runs well..

If you know someone with STAR or HHT, they can pull the digital codes underneath code 23 - the subcodes tell you if its a misfire (there is a code per cyl) or if its the ECU unable to read the current that it uses to check for correct spark production.

Are the plugs on the two indicated cylinders clean and the same colour as the other 4 ? (I know they are new, just looking to see if there is a problem in one cyl).

Finally, are the plugs the right ones - M104 is very sensitive to using the wrong "heat" of plug.
 
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kth286

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E320 Coupe 95
If the car is running properly it is unlikely the output stage from the ECU is blown, as there would be no input to the coil and two cylinders would not be firing, and you would certainly notice the car driving on only 4 cylinders.

so therefore it is likely an open circuit on only one cylinder which is often hard to detect on a 6 cylinder car.

The plug extenders often go faulty but you say you have fitted 3 new under coil extenders, and also you have new coil leads which also have the 2 k resistances built into the coil attachments to them.

So, what is likely causing the open circuit on one cylinder ?

It is highly likely you have not clicked on of the spark plug connections on properly.

So you need to take the top cover off again and make sure you positively click the plug connections on properly.

You will then likely have the full 6 cylinders working.

A side note.

Do not just pull the plug connections straight off BUT rotate them as you pull them off

You will find less force is required.
 

124coupe

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There are two functions to each output stage on the ECU, one to fire the coil and the other to measure the current flow - this latter function is used to determine if the spark was made correctly.

I suspect this part of the stage was damaged earlier when the original coil failed OR one of the cylinders is misfiring which was the reason for suggesting comparing the plugs.

The ideal way is to get the digital codes read that further explain blink code 23 - there are 4 digital codes for blink code 23.
 
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xitrum_dalat

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I have to say "many thanks" to all of nice guys, trying to
solve my question .

many suggestions I've done.

Today. I open coil cover, take off spark plugs ,coil , and plugs under coils.

all spark plugs look good color.
SO,I clean all contacts and spark plugs with degrease contact cleaner.

measure resistance for plug under coil it's 2 k ohm.

test ohm between plug to coil from ecu ( between it's self and others)

it seems OK, no different to all.

measure the core of spark plugs ,it's OK.


could it be like this-

b cause of the broken coil cause back fire many times.

so it damage VALVES.

Intake and exhaust valves in cylinder 3 or 4 maybe damaged.

And b cause of leak valves cause knock sensor learn that
the the ignition in cylinder 3 or 4 is not completed.

so now ,i realize that my rpm is a bit higher than other.
I surprise that my rpm at warm is 850 instead of 750-800


How about this theory ?
 

kth286

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E320 Coupe 95
No to valve problems.

If diagnostic code 23 is still showing then that is the fault - do not go wandering off on a tangent.

Are you absolutely sure the coils are earthed properly ? there is a peg that is important for the coil to fit properly.
 
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xitrum_dalat

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I'LL try to clean the ground bolts on valve cover again,

by sand paper.
 
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xitrum_dalat

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Update


today i open (again) valve cover,
then, connect ground wire hand-made to every coil by brass connectors.

result ..............

code........23 ..... again.



another theory is

the ignition on 3-4 has really miss fire , but, only when start period.

maybe
the circuit to coil when start , is another one when running.?
 
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xitrum_dalat

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For now, I'm waiting for another ECU from other car ,may be 2-3 days.
I'll try the other ECU if it's result will be the same.




Oh...code 23 annoy me too much.


imagine , when you drive you will really cannot feel the misfire .

but , the is a code indicated that, there are something wrong.
 

timmyr

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300E/1993/ M104 2.8L
did you ever resolve the missfire code?
 

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